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+

RFC 1002 (RFC1002)

+

Internet RFC/STD/FYI/BCP Archives

+ +
[ RFC Index | RFC Search | Usenet FAQs | Web FAQs | Documents | Cities ] +

+Alternate Formats: + rfc1002.txt | + rfc1002.txt.pdf

+

+

RFC 1002 - Protocol standard for a NetBIOS service on a TCP/UDP transport: Detailed specifications

+
+
+
+Network Working Group
+Request for Comments: 1002                         March, 1987
+
+             PROTOCOL STANDARD FOR A NetBIOS SERVICE
+                     ON A TCP/UDP TRANSPORT:
+                     DETAILED SPECIFICATIONS
+
+                            ABSTRACT
+
+This RFC defines a proposed standard protocol to support NetBIOS
+services in a TCP/IP environment.  Both local network and internet
+operation are supported.  Various node types are defined to accommodate
+local and internet topologies and to allow operation with or without the
+use of IP broadcast.
+
+This RFC gives the detailed specifications of the NetBIOS-over-TCP
+packets, protocols, and defined constants and variables.  A more general
+overview is found in a companion RFC, "Protocol Standard For a NetBIOS
+Service on a TCP/UDP Transport: Concepts and Methods".
+
+                        TABLE OF CONTENTS
+
+1.  STATUS OF THIS MEMO                                              4
+
+2.  ACKNOWLEDGEMENTS                                                 4
+
+3.  INTRODUCTION                                                     5
+
+4.  PACKET DESCRIPTIONS                                              5
+  4.1  NAME FORMAT                                                   5
+  4.2  NAME SERVICE PACKETS                                          7
+     4.2.1  GENERAL FORMAT OF NAME SERVICE PACKETS                   7
+       4.2.1.1  HEADER                                               8
+       4.2.1.2  QUESTION SECTION                                    10
+       4.2.1.3  RESOURCE RECORD                                     11
+     4.2.2  NAME REGISTRATION REQUEST                               13
+     4.2.3  NAME OVERWRITE REQUEST & DEMAND                         14
+     4.2.4  NAME REFRESH REQUEST                                    15
+     4.2.5  POSITIVE NAME REGISTRATION RESPONSE                     16
+     4.2.6  NEGATIVE NAME REGISTRATION RESPONSE                     16
+     4.2.7  END-NODE CHALLENGE REGISTRATION RESPONSE                17
+     4.2.8  NAME CONFLICT DEMAND                                    18
+     4.2.9  NAME RELEASE REQUEST & DEMAND                           19
+     4.2.10  POSITIVE NAME RELEASE RESPONSE                         20
+     4.2.11  NEGATIVE NAME RELEASE RESPONSE                         20
+     4.2.12  NAME QUERY REQUEST                                     21
+     4.2.13  POSITIVE NAME QUERY RESPONSE                           22
+     4.2.14  NEGATIVE NAME QUERY RESPONSE                           23
+     4.2.15  REDIRECT NAME QUERY RESPONSE                           24
+     4.2.16  WAIT FOR ACKNOWLEDGEMENT (WACK) RESPONSE               25
+     4.2.17  NODE STATUS REQUEST                                    26
+     4.2.18  NODE STATUS RESPONSE                                   27
+  4.3  SESSION SERVICE PACKETS                                      29
+     4.3.1  GENERAL FORMAT OF SESSION PACKETS                       29
+     4.3.2  SESSION REQUEST PACKET                                  30
+     4.3.3  POSITIVE SESSION RESPONSE PACKET                        31
+     4.3.4  NEGATIVE SESSION RESPONSE PACKET                        31
+     4.3.5  SESSION RETARGET RESPONSE PACKET                        31
+     4.3.6  SESSION MESSAGE PACKET                                  32
+     4.3.7  SESSION KEEP ALIVE PACKET                               32
+  4.4  DATAGRAM SERVICE PACKETS                                     32
+     4.4.1  NetBIOS DATAGRAM HEADER                                 32
+     4.4.2  DIRECT_UNIQUE, DIRECT_GROUP, & BROADCAST DATAGRAM       33
+     4.4.3  DATAGRAM ERROR PACKET                                   34
+     4.4.4  DATAGRAM QUERY REQUEST                                  34
+     4.4.5  DATAGRAM POSITIVE AND NEGATIVE QUERY RESPONSE           34
+
+5.  PROTOCOL DESCRIPTIONS                                           35
+  5.1  NAME SERVICE PROTOCOLS                                       35
+     5.1.1  B-NODE ACTIVITY                                         35
+
+       5.1.1.1  B-NODE ADD NAME                                     35
+       5.1.1.2  B-NODE ADD_GROUP NAME                               37
+       5.1.1.3  B-NODE FIND_NAME                                    37
+       5.1.1.4  B NODE NAME RELEASE                                 38
+       5.1.1.5  B-NODE INCOMING PACKET PROCESSING                   39
+     5.1.2  P-NODE ACTIVITY                                         42
+       5.1.2.1  P-NODE ADD_NAME                                     42
+       5.1.2.2  P-NODE ADD GROUP NAME                               45
+       5.1.2.3  P-NODE FIND NAME                                    45
+       5.1.2.4  P-NODE DELETE_NAME                                  46
+       5.1.2.5  P-NODE INCOMING PACKET PROCESSING                   47
+       5.1.2.6  P-NODE TIMER INITIATED PROCESSING                   49
+     5.1.3  M-NODE ACTIVITY                                         50
+       5.1.3.1  M-NODE ADD NAME                                     50
+       5.1.3.2  M-NODE ADD GROUP NAME                               54
+       5.1.3.3  M-NODE FIND NAME                                    55
+       5.1.3.4  M-NODE DELETE NAME                                  56
+       5.1.3.5  M-NODE INCOMING PACKET PROCESSING                   58
+       5.1.3.6  M-NODE TIMER INITIATED PROCESSING                   60
+     5.1.4  NBNS ACTIVITY                                           60
+       5.1.4.1  NBNS INCOMING PACKET PROCESSING                     61
+       5.1.4.2  NBNS TIMER INITIATED PROCESSING                     66
+  5.2  SESSION SERVICE PROTOCOLS                                    67
+     5.2.1  SESSION ESTABLISHMENT PROTOCOLS                         67
+       5.2.1.1  USER REQUEST PROCESSING                             67
+       5.2.1.2  RECEIVED PACKET PROCESSING                          71
+     5.2.2  SESSION DATA TRANSFER PROTOCOLS                         72
+       5.2.2.1  USER REQUEST PROCESSING                             72
+       5.2.2.2  RECEIVED PACKET PROCESSING                          72
+       5.2.2.3  PROCESSING INITIATED BY TIMER                       73
+     5.2.3  SESSION TERMINATION PROTOCOLS                           73
+       5.2.3.1  USER REQUEST PROCESSING                             73
+       5.2.3.2  RECEPTION INDICATION PROCESSING                     73
+  5.3  NetBIOS DATAGRAM SERVICE PROTOCOLS                           74
+     5.3.1  B NODE TRANSMISSION OF NetBIOS DATAGRAMS                74
+     5.3.2  P AND M NODE TRANSMISSION OF NetBIOS DATAGRAMS          76
+     5.3.3  RECEPTION OF NetBIOS DATAGRAMS BY ALL NODES             78
+     5.3.4  PROTOCOLS FOR THE NBDD                                  80
+
+6.  DEFINED CONSTANTS AND VARIABLES                                 83
+
+REFERENCES                                                          85
+
+             PROTOCOL STANDARD FOR A NetBIOS SERVICE
+                     ON A TCP/UDP TRANSPORT:
+                     DETAILED SPECIFICATIONS
+
+1.  STATUS OF THIS MEMO
+
+   This RFC specifies a proposed standard for the DARPA Internet
+   community.  Since this topic is new to the Internet community,
+   discussions and suggestions are specifically requested.
+
+   Please send written comments to:
+
+           Karl Auerbach
+           Epilogue Technology Corporation
+           P.O. Box 5432
+           Redwood City, CA   94063
+
+   Please send online comments to:
+
+           Avnish Aggarwal
+                   Internet: mtxinu!excelan!avnish@ucbvax.berkeley.edu
+                   Usenet:   ucbvax!mtxinu!excelan!avnish
+
+   Distribution of this memorandum is unlimited.
+
+2.  ACKNOWLEDGEMENTS
+
+   This RFC has been developed under the auspices of the Internet
+   Activities Board.
+
+   The following individuals have contributed to the development of
+   this RFC:
+
+   Avnish Aggarwal       Arvind Agrawal        Lorenzo Aguilar
+   Geoffrey Arnold       Karl Auerbach         K. Ramesh Babu
+   Keith Ball            Amatzia Ben-Artzi     Vint Cerf
+   Richard Cherry        David Crocker         Steve Deering
+   Greg Ennis            Steve Holmgren        Jay Israel
+   David Kaufman         Lee LaBarre           James Lau
+   Dan Lynch             Gaylord Miyata        David Stevens
+   Steve Thomas          Ishan Wu
+
+   The system proposed by this RFC does not reflect any existing
+   Netbios-over-TCP implementation.  However, the design
+   incorporates considerable knowledge obtained from prior
+   implementations.  Special thanks goes to the following
+   organizations which have provided this invaluable information:
+
+   CMC/Syros      Excelan        Sytek          Ungermann-Bass
+
+3.  INTRODUCTION
+
+   This RFC contains the detailed packet formats and protocol
+   specifications for NetBIOS-over-TCP.  This RFC is a companion to
+   RFC 1001, "Protocol Standard For a NetBIOS Service on a TCP/UDP
+   Transport: Concepts and Methods" [1].
+
+4.  PACKET DESCRIPTIONS
+
+   Bit and byte ordering are defined by the most recent version of
+   "Assigned Numbers" [2].
+
+4.1.  NAME FORMAT
+
+   The NetBIOS name representation in all NetBIOS packets (for NAME,
+   SESSION, and DATAGRAM services) is defined in the Domain Name
+   Service RFC 883[3] as "compressed" name messages.  This format is
+   called "second-level encoding" in the section entitled
+   "Representation of NetBIOS Names" in the Concepts and Methods
+   document.
+
+   For ease of description, the first two paragraphs from page 31,
+   the section titled "Domain name representation and compression",
+   of RFC 883 are replicated here:
+
+        Domain names messages are expressed in terms of a sequence
+        of labels.  Each label is represented as a one octet length
+        field followed by that number of octets.  Since every domain
+        name ends with the null label of the root, a compressed
+        domain name is terminated by a length byte of zero.  The
+        high order two bits of the length field must be zero, and
+        the remaining six bits of the length field limit the label
+        to 63 octets or less.
+
+        To simplify implementations, the total length of label
+        octets and label length octets that make up a domain name is
+        restricted to 255 octets or less.
+
+   The following is the uncompressed representation of the NetBIOS name
+   "FRED ", which is the 4 ASCII characters, F, R, E, D, followed by 12
+   space characters (0x20).  This name has the SCOPE_ID: "NETBIOS.COM"
+
+           EGFCEFEECACACACACACACACACACACACA.NETBIOS.COM
+
+   This uncompressed representation of names is called "first-level
+   encoding" in the section entitled "Representation of NetBIOS Names"
+   in the Concepts and Methods document.
+
+   The following is a pictographic representation of the compressed
+   representation of the previous uncompressed Domain Name
+   representation.
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |      0x20     |    E (0x45)   |    G (0x47)   |    F (0x46)   |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |    C (0x43)   |    E (0x45)   |    F (0x46)   |    E (0x45)   |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |    E (0x45)   |    C (0x43)   |    A (0x41)   |    C (0x43)   |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |    A (0x41)   |    C (0x43)   |    A (0x41)   |    C (0x43)   |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |    A (0x41)   |    C (0x43)   |    A (0x41)   |    C (0x43)   |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |    A (0x41)   |    C (0x43)   |    A (0x41)   |    C (0x43)   |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |    A (0x41)   |    C (0x43)   |    A (0x41)   |    C (0x43)   |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |    A (0x41)   |    C (0x43)   |    A (0x41)   |    C (0x43)   |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |    A (0X41)   |      0x07     |    N (0x4E)   |    E (0x45)   |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |    T (0x54)   |    B (0x42)   |    I (0x49)   |    O (0x4F)   |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |    S (0x53)   |      0x03     |    C (0x43)   |    O (0x4F)   |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |    M (0x4D)   |      0x00     |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+   Each section of a domain name is called a label [7 (page 31)].  A
+   label can be a maximum of 63 bytes.  The first byte of a label in
+   compressed representation is the number of bytes in the label.  For
+   the above example, the first 0x20 is the number of bytes in the
+   left-most label, EGFCEFEECACACACACACACACACACACACA, of the domain
+   name.  The bytes following the label length count are the characters
+   of the label.  The following labels are in sequence after the first
+   label, which is the encoded NetBIOS name, until a zero (0x00) length
+   count.  The zero length count represents the root label, which is
+   always null.
+
+   A label length count is actually a 6-bit field in the label length
+   field.  The most significant 2 bits of the field, bits 7 and 6, are
+   flags allowing an escape from the above compressed representation.
+   If bits 7 and 6 are both set (11), the following 14 bits are an
+   offset pointer into the full message to the actual label string from
+   another domain name that belongs in this name.  This label pointer
+   allows for a further compression of a domain name in a packet.
+
+   NetBIOS implementations can only use label string pointers in Name
+   Service packets.  They cannot be used in Session or Datagram Service
+   packets.
+
+   The other two possible values for bits 7 and 6 (01 and 10) of a label
+   length field are reserved for future use by RFC 883[2 (page 32)].
+
+   Note that the first octet of a compressed name must contain one of
+   the following bit patterns.  (An "x" indicates a bit whose value may
+   be either 0 or 1.):
+
+           00100000 -  Netbios name, length must be 32 (decimal)
+           11xxxxxx -  Label string pointer
+           10xxxxxx -  Reserved
+           01xxxxxx -  Reserved
+
+4.2.  NAME SERVICE PACKETS
+
+4.2.1.  GENERAL FORMAT OF NAME SERVICE PACKETS
+
+   The NetBIOS Name Service packets follow the packet structure defined
+   in the Domain Name Service (DNS) RFC 883 [7 (pg 26-31)].  The
+   structures are compatible with the existing DNS packet formats,
+   however, additional types and codes have been added to work with
+   NetBIOS.
+
+   If Name Service packets are sent over a TCP connection they are
+   preceded by a 16 bit unsigned integer representing the length of the
+   Name Service packet.
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   + ------                                                ------- +
+   |                            HEADER                             |
+   + ------                                                ------- +
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                       QUESTION ENTRIES                        /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                    ANSWER RESOURCE RECORDS                    /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                  AUTHORITY RESOURCE RECORDS                   /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                  ADDITIONAL RESOURCE RECORDS                  /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+4.2.1.1.  HEADER
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         NAME_TRN_ID           | OPCODE  |   NM_FLAGS  | RCODE |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          QDCOUNT              |           ANCOUNT             |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          NSCOUNT              |           ARCOUNT             |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+   Field     Description
+
+   NAME_TRN_ID      Transaction ID for Name Service Transaction.
+                    Requestor places a unique value for each active
+                    transaction.  Responder puts NAME_TRN_ID value
+                    from request packet in response packet.
+
+   OPCODE           Packet type code, see table below.
+
+   NM_FLAGS         Flags for operation, see table below.
+
+   RCODE            Result codes of request.  Table of RCODE values
+                    for each response packet below.
+
+   QDCOUNT          Unsigned 16 bit integer specifying the number of
+                    entries in the question section of a Name
+
+                    Service packet.  Always zero (0) for responses.
+                    Must be non-zero for all NetBIOS Name requests.
+
+   ANCOUNT          Unsigned 16 bit integer specifying the number of
+                    resource records in the answer section of a Name
+                    Service packet.
+
+   NSCOUNT          Unsigned 16 bit integer specifying the number of
+                    resource records in the authority section of a
+                    Name Service packet.
+
+   ARCOUNT          Unsigned 16 bit integer specifying the number of
+                    resource records in the additional records
+                    section of a Name Service packet.
+
+   The OPCODE field is defined as:
+
+     0   1   2   3   4
+   +---+---+---+---+---+
+   | R |    OPCODE     |
+   +---+---+---+---+---+
+
+   Symbol     Bit(s)   Description
+
+   OPCODE        1-4   Operation specifier:
+                         0 = query
+                         5 = registration
+                         6 = release
+                         7 = WACK
+                         8 = refresh
+
+   R               0   RESPONSE flag:
+                         if bit == 0 then request packet
+                         if bit == 1 then response packet.
+
+   The NM_FLAGS field is defined as:
+
+     0   1   2   3   4   5   6
+   +---+---+---+---+---+---+---+
+   |AA |TC |RD |RA | 0 | 0 | B |
+   +---+---+---+---+---+---+---+
+
+   Symbol     Bit(s)   Description
+
+   B               6   Broadcast Flag.
+                         = 1: packet was broadcast or multicast
+                         = 0: unicast
+
+   RA              3   Recursion Available Flag.
+
+                       Only valid in responses from a NetBIOS Name
+                       Server -- must be zero in all other
+                       responses.
+
+                       If one (1) then the NBNS supports recursive
+                       query, registration, and release.
+
+                       If zero (0) then the end-node must iterate
+                       for query and challenge for registration.
+
+   RD              2   Recursion Desired Flag.
+
+                       May only be set on a request to a NetBIOS
+                       Name Server.
+
+                       The NBNS will copy its state into the
+                       response packet.
+
+                       If one (1) the NBNS will iterate on the
+                       query, registration, or release.
+
+   TC              1   Truncation Flag.
+
+                       Set if this message was truncated because the
+                       datagram carrying it would be greater than
+                       576 bytes in length.  Use TCP to get the
+                       information from the NetBIOS Name Server.
+
+   AA              0   Authoritative Answer flag.
+
+                       Must be zero (0) if R flag of OPCODE is zero
+                       (0).
+
+                       If R flag is one (1) then if AA is one (1)
+                       then the node responding is an authority for
+                       the domain name.
+
+                       End nodes responding to queries always set
+                       this bit in responses.
+
+4.2.1.2.  QUESTION SECTION
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                         QUESTION_NAME                         /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         QUESTION_TYPE         |        QUESTION_CLASS         |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+   Field            Description
+
+   QUESTION_NAME    The compressed name representation of the
+                    NetBIOS name for the request.
+
+   QUESTION_TYPE    The type of request.  The values for this field
+                    are specified for each request.
+
+   QUESTION_CLASS   The class of the request.  The values for this
+                    field are specified for each request.
+
+   QUESTION_TYPE is defined as:
+
+   Symbol      Value   Description:
+
+   NB         0x0020   NetBIOS general Name Service Resource Record
+   NBSTAT     0x0021   NetBIOS NODE STATUS Resource Record (See NODE
+                       STATUS REQUEST)
+
+   QUESTION_CLASS is defined as:
+
+   Symbol      Value   Description:
+
+   IN         0x0001   Internet class
+
+4.2.1.3.  RESOURCE RECORD
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                            RR_NAME                            /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           RR_TYPE             |          RR_CLASS             |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                              TTL                              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           RDLENGTH            |                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
+   /                                                               /
+   /                             RDATA                             /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+   Field            Description
+
+   RR_NAME          The compressed name representation of the
+                    NetBIOS name corresponding to this resource
+                    record.
+
+   RR_TYPE          Resource record type code
+
+   RR_CLASS         Resource record class code
+
+   TTL              The Time To Live of a the resource record's
+                    name.
+
+   RDLENGTH         Unsigned 16 bit integer that specifies the
+                    number of bytes in the RDATA field.
+
+   RDATA            RR_CLASS and RR_TYPE dependent field.  Contains
+                    the resource information for the NetBIOS name.
+
+   RESOURCE RECORD RR_TYPE field definitions:
+
+   Symbol      Value   Description:
+
+   A          0x0001   IP address Resource Record (See REDIRECT NAME
+                       QUERY RESPONSE)
+   NS         0x0002   Name Server Resource Record (See REDIRECT
+
+                       NAME QUERY RESPONSE)
+   NULL       0x000A   NULL Resource Record (See WAIT FOR
+                       ACKNOWLEDGEMENT RESPONSE)
+   NB         0x0020   NetBIOS general Name Service Resource Record
+                       (See NB_FLAGS and NB_ADDRESS, below)
+   NBSTAT     0x0021   NetBIOS NODE STATUS Resource Record (See NODE
+                       STATUS RESPONSE)
+
+   RESOURCE RECORD RR_CLASS field definitions:
+
+   Symbol      Value   Description:
+
+   IN         0x0001   Internet class
+
+   NB_FLAGS field of the RESOURCE RECORD RDATA field for RR_TYPE of
+   "NB":
+
+                                             1   1   1   1   1   1
+     0   1   2   3   4   5   6   7   8   9   0   1   2   3   4   5
+   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+   | G |  ONT  |                RESERVED                           |
+   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+
+   Symbol     Bit(s)   Description:
+
+   RESERVED     3-15   Reserved for future use.  Must be zero (0).
+   ONT           1,2   Owner Node Type:
+                          00 = B node
+                          01 = P node
+                          10 = M node
+                          11 = Reserved for future use
+                       For registration requests this is the
+                       claimant's type.
+                       For responses this is the actual owner's
+                       type.
+
+   G               0   Group Name Flag.
+                       If one (1) then the RR_NAME is a GROUP
+                       NetBIOS name.
+                       If zero (0) then the RR_NAME is a UNIQUE
+                       NetBIOS name.
+
+   The NB_ADDRESS field of the RESOURCE RECORD RDATA field for
+   RR_TYPE of "NB" is the IP address of the name's owner.
+
+4.2.2.  NAME REGISTRATION REQUEST
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         NAME_TRN_ID           |0|  0x5  |0|0|1|0|0 0|B|  0x0  |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0001               |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0001              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                         QUESTION_NAME                         /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           NB (0x0020)         |        IN (0x0001)            |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                            RR_NAME                            /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           NB (0x0020)         |         IN (0x0001)           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                              TTL                              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           0x0006              |          NB_FLAGS             |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                          NB_ADDRESS                           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+   Since the RR_NAME is the same name as the QUESTION_NAME, the
+   RR_NAME representation must use pointers to the QUESTION_NAME
+   name's labels to guarantee the length of the datagram is less
+   than the maximum 576 bytes.  See section above on name formats
+   and also page 31 and 32 of RFC 883, Domain Names - Implementation
+   and Specification, for a complete description of compressed name
+   label pointers.
+
+4.2.3.  NAME OVERWRITE REQUEST & DEMAND
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         NAME_TRN_ID           |0|  0x5  |0|0|0|0|0 0|B|  0x0  |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0001               |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0001              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                         QUESTION_NAME                         /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           NB (0x0020)         |        IN (0x0001)            |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                            RR_NAME                            /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           NB (0x0020)         |         IN (0x0001)           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                              TTL                              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           0x0006              |          NB_FLAGS             |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                          NB_ADDRESS                           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+4.2.4.  NAME REFRESH REQUEST
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         NAME_TRN_ID           |0|  0x9  |0|0|0|0|0 0|B|  0x0  |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0001               |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0001              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                         QUESTION_NAME                         /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           NB (0x0020)         |        IN (0x0001)            |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                            RR_NAME                            /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           NB (0x0020)         |         IN (0x0001)           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                              TTL                              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           0x0006              |          NB_FLAGS             |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                          NB_ADDRESS                           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+4.2.5.  POSITIVE NAME REGISTRATION RESPONSE
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         NAME_TRN_ID           |1|  0x5  |1|0|1|1|0 0|0|  0x0  |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0001              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                            RR_NAME                            /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           NB (0x0020)         |         IN (0x0001)           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                              TTL                              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           0x0006              |          NB_FLAGS             |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                          NB_ADDRESS                           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+4.2.6.  NEGATIVE NAME REGISTRATION RESPONSE
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         NAME_TRN_ID           |1|  0x5  |1|0|1|1|0 0|0| RCODE |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0001              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                            RR_NAME                            /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           NB (0x0020)         |         IN (0x0001)           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                              TTL                              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           0x0006              |          NB_FLAGS             |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                          NB_ADDRESS                           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+   RCODE field values:
+
+   Symbol      Value   Description:
+
+   FMT_ERR       0x1   Format Error.  Request was invalidly
+                       formatted.
+   SRV_ERR       0x2   Server failure.  Problem with NBNS, cannot
+                       process name.
+   IMP_ERR       0x4   Unsupported request error.  Allowable only
+                       for challenging NBNS when gets an Update type
+                       registration request.
+   RFS_ERR       0x5   Refused error.  For policy reasons server
+                       will not register this name from this host.
+   ACT_ERR       0x6   Active error.  Name is owned by another node.
+   CFT_ERR       0x7   Name in conflict error.  A UNIQUE name is
+                       owned by more than one node.
+
+4.2.7.  END-NODE CHALLENGE REGISTRATION RESPONSE
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         NAME_TRN_ID           |1|  0x5  |1|0|1|0|0 0|0|  0x0  |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0001              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                            RR_NAME                            /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           NB (0x0020)         |         IN (0x0001)           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                              TTL                              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           0x0006              |          NB_FLAGS             |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                          NB_ADDRESS                           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+4.2.8.  NAME CONFLICT DEMAND
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         NAME_TRN_ID           |1|  0x5  |1|0|1|1|0 0|0|  0x7  |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0001              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                            RR_NAME                            /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           NB (0x0020)         |         IN (0x0001)           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                          0x00000000                           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           0x0006              |0|ONT|0|     0x000             |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                          0x00000000                           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+   This packet is identical to a NEGATIVE NAME REGISTRATION RESPONSE
+   with RCODE = CFT_ERR.
+
+4.2.9.  NAME RELEASE REQUEST & DEMAND
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         NAME_TRN_ID           |0|  0x6  |0|0|0|0|0 0|B|  0x0  |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0001               |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0001              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                         QUESTION_NAME                         /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           NB (0x0020)         |        IN (0x0001)            |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                            RR_NAME                            /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           NB (0x0020)         |         IN (0x0001)           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                          0x00000000                           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           0x0006              |          NB_FLAGS             |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                          NB_ADDRESS                           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+   Since the RR_NAME is the same name as the QUESTION_NAME, the
+   RR_NAME representation must use label string pointers to the
+   QUESTION_NAME labels to guarantee the length of the datagram is
+   less than the maximum 576 bytes.  This is the same condition as
+   with the NAME REGISTRATION REQUEST.
+
+4.2.10.  POSITIVE NAME RELEASE RESPONSE
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         NAME_TRN_ID           |1|  0x6  |1|0|0|0|0 0|0|  0x0  |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0001              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                            RR_NAME                            /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           NB (0x0020)         |         IN (0x0001)           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                              TTL                              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           0x0006              |          NB_FLAGS             |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                          NB_ADDRESS                           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+4.2.11.  NEGATIVE NAME RELEASE RESPONSE
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         NAME_TRN_ID           |1|  0x6  |1|0|0|0|0 0|0| RCODE |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0001              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                            RR_NAME                            /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           NB (0x0020)         |         IN (0x0001)           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                              TTL                              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           0x0006              |          NB_FLAGS             |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                          NB_ADDRESS                           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+   RCODE field values:
+
+   Symbol      Value   Description:
+
+   FMT_ERR       0x1   Format Error.  Request was invalidly
+                       formatted.
+
+   SRV_ERR       0x2   Server failure.  Problem with NBNS, cannot
+                       process name.
+
+   RFS_ERR       0x5   Refused error.  For policy reasons server
+                       will not release this name from this host.
+
+   ACT_ERR       0x6   Active error.  Name is owned by another node.
+                       Only that node may release it.  A NetBIOS
+                       Name Server can optionally allow a node to
+                       release a name it does not own.  This would
+                       facilitate detection of inactive names for
+                       nodes that went down silently.
+
+4.2.12.  NAME QUERY REQUEST
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         NAME_TRN_ID           |0|  0x0  |0|0|1|0|0 0|B|  0x0  |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0001               |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                         QUESTION_NAME                         /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           NB (0x0020)         |        IN (0x0001)            |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+4.2.13.  POSITIVE NAME QUERY RESPONSE
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         NAME_TRN_ID           |1|  0x0  |1|T|1|?|0 0|0|  0x0  |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0001              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                            RR_NAME                            /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           NB (0x0020)         |         IN (0x0001)           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                              TTL                              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           RDLENGTH            |                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
+   |                                                               |
+   /                       ADDR_ENTRY ARRAY                        /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+   The ADDR_ENTRY ARRAY a sequence of zero or more ADDR_ENTRY
+   records.  Each ADDR_ENTRY record represents an owner of a name.
+   For group names there may be multiple entries.  However, the list
+   may be incomplete due to packet size limitations.  Bit 22, "T",
+   will be set to indicate truncated data.
+
+   Each ADDR_ENTRY has the following format:
+
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          NB_FLAGS             |          NB_ADDRESS           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |   NB_ADDRESS (continued)      |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+4.2.14.  NEGATIVE NAME QUERY RESPONSE
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         NAME_TRN_ID           |1|  0x0  |1|0|1|?|0 0|0| RCODE |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                            RR_NAME                            /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           NULL (0x000A)       |         IN (0x0001)           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                          0x00000000                           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+   RCODE field values:
+
+   Symbol      Value   Description
+
+   FMT_ERR       0x1   Format Error.  Request was invalidly
+                       formatted.
+   SRV_ERR       0x2   Server failure.  Problem with NBNS, cannot
+                       process name.
+   NAM_ERR       0x3   Name Error.  The name requested does not
+                       exist.
+   IMP_ERR       0x4   Unsupported request error.  Allowable only
+                       for challenging NBNS when gets an Update type
+                       registration request.
+   RFS_ERR       0x5   Refused error.  For policy reasons server
+                       will not register this name from this host.
+
+4.2.15.  REDIRECT NAME QUERY RESPONSE
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         NAME_TRN_ID           |1|  0x0  |0|0|1|0|0 0|0|  0x0  |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0001               |           0x0001              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                            RR_NAME                            /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           NS (0x0002)         |         IN (0x0001)           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                              TTL                              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           RDLENGTH            |                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
+   |                                                               |
+   /                            NSD_NAME                           /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                            RR_NAME                            /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           A (0x0001)          |         IN (0x0001)           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                              TTL                              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |             0x0004            |           NSD_IP_ADDR         |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |     NSD_IP_ADDR, continued    |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+   An end node responding to a NAME QUERY REQUEST always responds
+   with the AA and RA bits set for both the NEGATIVE and POSITIVE
+   NAME QUERY RESPONSE packets.  An end node never sends a REDIRECT
+   NAME QUERY RESPONSE packet.
+
+   When the requestor receives the REDIRECT NAME QUERY RESPONSE it
+   must reiterate the NAME QUERY REQUEST to the NBNS specified by
+   the NSD_IP_ADDR field of the A type RESOURCE RECORD in the
+   ADDITIONAL section of the response packet.  This is an optional
+   packet for the NBNS.
+
+   The NSD_NAME and the RR_NAME in the ADDITIONAL section of the
+   response packet are the same name.  Space can be optimized if
+   label string pointers are used in the RR_NAME which point to the
+   labels in the NSD_NAME.
+
+   The RR_NAME in the AUTHORITY section is the name of the domain
+   the NBNS called by NSD_NAME has authority over.
+
+4.2.16.  WAIT FOR ACKNOWLEDGEMENT (WACK) RESPONSE
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         NAME_TRN_ID           |1|  0x7  |1|0|0|0|0 0|0|  0x0  |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0001              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                            RR_NAME                            /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          NULL (0x0020)        |         IN (0x0001)           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                              TTL                              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           0x0002              | OPCODE  |   NM_FLAGS  |  0x0  |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+   The NAME_TRN_ID of the WACK RESPONSE packet is the same
+   NAME_TRN_ID of the request that the NBNS is telling the requestor
+   to wait longer to complete.  The RR_NAME is the name from the
+   request, if any.  If no name is available from the request then
+   it is a null name, single byte of zero.
+
+   The TTL field of the ResourceRecord is the new time to wait, in
+   seconds, for the request to complete.  The RDATA field contains
+   the OPCODE and NM_FLAGS of the request.
+
+   A TTL value of 0 means that the NBNS can not estimate the time it
+   may take to complete a response.
+
+4.2.17.  NODE STATUS REQUEST
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         NAME_TRN_ID           |0|  0x0  |0|0|0|0|0 0|B|  0x0  |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0001               |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                         QUESTION_NAME                         /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         NBSTAT (0x0021)       |        IN (0x0001)            |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+4.2.18.  NODE STATUS RESPONSE
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         NAME_TRN_ID           |1|  0x0  |1|0|0|0|0 0|0|  0x0  |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0001              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          0x0000               |           0x0000              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                            RR_NAME                            /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |        NBSTAT (0x0021)        |         IN (0x0001)           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                          0x00000000                           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          RDLENGTH             |   NUM_NAMES   |               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+               +
+   |                                                               |
+   +                                                               +
+   /                         NODE_NAME ARRAY                       /
+   +                                                               +
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   +                                                               +
+   /                           STATISTICS                          /
+   +                                                               +
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+   The NODE_NAME ARRAY is an array of zero or more NUM_NAMES entries
+   of NODE_NAME records.  Each NODE_NAME entry represents an active
+   name in the same NetBIOS scope as the requesting name in the
+   local name table of the responder.  RR_NAME is the requesting
+   name.
+
+   NODE_NAME Entry:
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   +---                                                         ---+
+   |                                                               |
+   +---                    NETBIOS FORMAT NAME                  ---+
+   |                                                               |
+   +---                                                         ---+
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         NAME_FLAGS            |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+   The NAME_FLAGS field:
+
+                                             1   1   1   1   1   1
+     0   1   2   3   4   5   6   7   8   9   0   1   2   3   4   5
+   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+   | G |  ONT  |DRG|CNF|ACT|PRM|          RESERVED                 |
+   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+
+   The NAME_FLAGS field is defined as:
+
+   Symbol     Bit(s)   Description:
+
+   RESERVED     7-15   Reserved for future use.  Must be zero (0).
+   PRM             6   Permanent Name Flag.  If one (1) then entry
+                       is for the permanent node name.  Flag is zero
+                       (0) for all other names.
+   ACT             5   Active Name Flag.  All entries have this flag
+                       set to one (1).
+   CNF             4   Conflict Flag.  If one (1) then name on this
+                       node is in conflict.
+   DRG             3   Deregister Flag.  If one (1) then this name
+                       is in the process of being deleted.
+   ONT           1,2   Owner Node Type:
+                          00 = B node
+                          01 = P node
+                          10 = M node
+                          11 = Reserved for future use
+   G               0   Group Name Flag.
+                       If one (1) then the name is a GROUP NetBIOS
+                       name.
+                       If zero (0) then it is a UNIQUE NetBIOS name.
+
+   STATISTICS Field of the NODE STATUS RESPONSE:
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |               UNIT_ID (Unique unit ID)                        |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |       UNIT_ID,continued       |    JUMPERS    |  TEST_RESULT  |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |       VERSION_NUMBER          |      PERIOD_OF_STATISTICS     |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |       NUMBER_OF_CRCs          |     NUMBER_ALIGNMENT_ERRORS   |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |       NUMBER_OF_COLLISIONS    |        NUMBER_SEND_ABORTS     |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                       NUMBER_GOOD_SENDS                       |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                      NUMBER_GOOD_RECEIVES                     |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |       NUMBER_RETRANSMITS      | NUMBER_NO_RESOURCE_CONDITIONS |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |  NUMBER_FREE_COMMAND_BLOCKS   |  TOTAL_NUMBER_COMMAND_BLOCKS  |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |MAX_TOTAL_NUMBER_COMMAND_BLOCKS|    NUMBER_PENDING_SESSIONS    |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |  MAX_NUMBER_PENDING_SESSIONS  |  MAX_TOTAL_SESSIONS_POSSIBLE  |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |   SESSION_DATA_PACKET_SIZE    |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+4.3.  SESSION SERVICE PACKETS
+
+4.3.1.  GENERAL FORMAT OF SESSION PACKETS
+
+   All session service messages are sent over a TCP connection.
+
+   All session packets are of the following general structure:
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |      TYPE     |     FLAGS     |            LENGTH             |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /               TRAILER (Packet Type Dependent)                 /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+   The TYPE, FLAGS, and LENGTH fields are present in every session
+   packet.
+
+   The LENGTH field is the number of bytes following the LENGTH
+   field.  In other words, LENGTH is the combined size of the
+   TRAILER field(s).  For example, the POSITIVE SESSION RESPONSE
+   packet always has a LENGTH field value of zero (0000) while the
+   RETARGET SESSION RESPONSE always has a LENGTH field value of six
+   (0006).
+
+   One of the bits of the FLAGS field acts as an additional, high-
+   order bit for the LENGTH field.  Thus the cumulative size of the
+   trailer field(s) may range from 0 to 128K bytes.
+
+   Session Packet Types (in hexidecimal):
+
+           00 -  SESSION MESSAGE
+           81 -  SESSION REQUEST
+           82 -  POSITIVE SESSION RESPONSE
+           83 -  NEGATIVE SESSION RESPONSE
+           84 -  RETARGET SESSION RESPONSE
+           85 -  SESSION KEEP ALIVE
+
+   Bit definitions of the FLAGS field:
+
+     0   1   2   3   4   5   6   7
+   +---+---+---+---+---+---+---+---+
+   | 0 | 0 | 0 | 0 | 0 | 0 | 0 | E |
+   +---+---+---+---+---+---+---+---+
+
+   Symbol     Bit(s)   Description
+
+   E               7   Length extension, used as an additional,
+                       high-order bit on the LENGTH field.
+
+   RESERVED      0-6   Reserved, must be zero (0)
+
+4.3.2.  SESSION REQUEST PACKET
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |      TYPE     |     FLAGS     |            LENGTH             |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                          CALLED NAME                          /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                          CALLING NAME                         /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+4.3.3.  POSITIVE SESSION RESPONSE PACKET
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |      TYPE     |     FLAGS     |            LENGTH             |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+4.3.4.  NEGATIVE SESSION RESPONSE PACKET
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |      TYPE     |     FLAGS     |            LENGTH             |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |   ERROR_CODE  |
+   +-+-+-+-+-+-+-+-+
+
+   NEGATIVE SESSION RESPONSE packet error code values (in
+   hexidecimal):
+
+           80 -  Not listening on called name
+           81 -  Not listening for calling name
+           82 -  Called name not present
+           83 -  Called name present, but insufficient resources
+           8F -  Unspecified error
+
+4.3.5.  SESSION RETARGET RESPONSE PACKET
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |      TYPE     |     FLAGS     |            LENGTH             |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                      RETARGET_IP_ADDRESS                      |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |           PORT                |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+4.3.6.  SESSION MESSAGE PACKET
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |      TYPE     |     FLAGS     |            LENGTH             |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                                                               /
+   /                           USER_DATA                           /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+4.3.7.  SESSION KEEP ALIVE PACKET
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |      TYPE     |     FLAGS     |            LENGTH             |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+4.4.  DATAGRAM SERVICE PACKETS
+
+4.4.1.  NetBIOS DATAGRAM HEADER
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |   MSG_TYPE    |     FLAGS     |           DGM_ID              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                           SOURCE_IP                           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          SOURCE_PORT          |          DGM_LENGTH           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         PACKET_OFFSET         |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+   MSG_TYPE values (in hexidecimal):
+
+           10 -  DIRECT_UNIQUE DATAGRAM
+           11 -  DIRECT_GROUP DATAGRAM
+           12 -  BROADCAST DATAGRAM
+           13 -  DATAGRAM ERROR
+           14 -  DATAGRAM QUERY REQUEST
+           15 -  DATAGRAM POSITIVE QUERY RESPONSE
+           16 -  DATAGRAM NEGATIVE QUERY RESPONSE
+
+   Bit definitions of the FLAGS field:
+
+     0   1   2   3   4   5   6   7
+   +---+---+---+---+---+---+---+---+
+   | 0 | 0 | 0 | 0 |  SNT  | F | M |
+   +---+---+---+---+---+---+---+---+
+
+   Symbol     Bit(s)   Description
+
+   M               7   MORE flag, If set then more NetBIOS datagram
+                       fragments follow.
+
+   F               6   FIRST packet flag,  If set then this is first
+                       (and possibly only) fragment of NetBIOS
+                       datagram
+
+   SNT           4,5   Source End-Node type:
+                          00 = B node
+                          01 = P node
+                          10 = M node
+                          11 = NBDD
+   RESERVED      0-3   Reserved, must be zero (0)
+
+4.4.2.  DIRECT_UNIQUE, DIRECT_GROUP, & BROADCAST DATAGRAM
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |   MSG_TYPE    |     FLAGS     |           DGM_ID              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                           SOURCE_IP                           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          SOURCE_PORT          |          DGM_LENGTH           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |         PACKET_OFFSET         |                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
+   |                                                               |
+   /                          SOURCE_NAME                          /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                       DESTINATION_NAME                        /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               |
+   /                           USER_DATA                           /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+   4.4.3.  DATAGRAM ERROR PACKET
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |   MSG_TYPE    |     FLAGS     |           DGM_ID              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                           SOURCE_IP                           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          SOURCE_PORT          |  ERROR_CODE   |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+   ERROR_CODE values (in hexidecimal):
+
+           82 -  DESTINATION NAME NOT PRESENT
+           83 -  INVALID SOURCE NAME FORMAT
+           84 -  INVALID DESTINATION NAME FORMAT
+
+4.4.4.  DATAGRAM QUERY REQUEST
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |   MSG_TYPE    |     FLAGS     |           DGM_ID              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                           SOURCE_IP                           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          SOURCE_PORT          |                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
+   |                                                               |
+   /                       DESTINATION_NAME                        /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+4.4.5.  DATAGRAM POSITIVE AND NEGATIVE QUERY RESPONSE
+
+                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |   MSG_TYPE    |     FLAGS     |           DGM_ID              |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                           SOURCE_IP                           |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |          SOURCE_PORT          |                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
+   |                                                               |
+   /                       DESTINATION_NAME                        /
+   /                                                               /
+   |                                                               |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+5.  PROTOCOL DESCRIPTIONS
+
+5.1.  NAME SERVICE PROTOCOLS
+
+   A REQUEST packet is always sent to the well known UDP port -
+   NAME_SERVICE_UDP_PORT.  The destination address is normally
+   either the IP broadcast address or the address of the NBNS - the
+   address of the NBNS server it set up at initialization time.  In
+   rare cases, a request packet will be sent to an end node, e.g.  a
+   NAME QUERY REQUEST sent to "challenge" a node.
+
+   A RESPONSE packet is always sent to the source UDP port and
+   source IP address of the request packet.
+
+   A DEMAND packet must always be sent to the well known UDP port -
+   NAME_SERVICE_UDP_PORT.  There is no restriction on the target IP
+   address.
+
+   Terms used in this section:
+
+   tid -            Transaction ID.  This is a value composed from
+                    the requestor's IP address and a unique 16 bit
+                    value generated by the originator of the
+                    transaction.
+
+5.1.1.  B-NODE ACTIVITY
+
+5.1.1.1.  B-NODE ADD NAME
+
+   PROCEDURE add_name(newname)
+
+   /*
+    * Host initiated processing for a B node
+    */
+   BEGIN
+
+        REPEAT
+
+             /* build name service packet */
+
+             ONT = B_NODE; /* broadcast node */
+             G = UNIQUE;   /* unique name */
+             TTL = 0;
+
+             broadcast NAME REGISTRATION REQUEST packet;
+
+             /*
+              * remote node(s) will send response packet
+              * if applicable
+              */
+
+             pause(BCAST_REQ_RETRY_TIMEOUT);
+
+        UNTIL response packet is received or
+             retransmit count has been exceeded
+
+        IF no response packet was received THEN
+        BEGIN /* no response */
+             /*
+              * build packet
+              */
+
+             ONT = B_NODE; /* broadcast node */
+             G = UNIQUE;   /* unique name */
+             TTL = 0;
+
+             /*
+              * Let other nodes known you have the name
+              */
+
+             broadcast NAME UPDATE REQUEST packet;
+             /* name can be added to local name table */
+             return success;
+        END /* no response */
+        ELSE
+        BEGIN /* got response */
+
+             /*
+              * Match return transaction id
+              * against tid sent in request
+              */
+
+            IF NOT response tid = request tid THEN
+            BEGIN
+             ignore response packet;
+            END
+            ELSE
+            CASE packet type OF
+
+            NEGATIVE NAME REGISTRATION RESPONSE:
+
+                 return failure; /* name cannot be added */
+
+            POSITIVE NAME REGISTRATION RESPONSE:
+            END-NODE CHALLENGE NAME REGISTRATION RESPONSE:
+
+                 /*
+                  * B nodes should normally not get this
+                  * response.
+                  */
+
+                  ignore packet;
+
+            END /* case */;
+        END /* got response */
+   END /* procedure */
+
+5.1.1.2.  B-NODE ADD_GROUP NAME
+
+   PROCEDURE add_group_name(newname)
+
+   /*
+    * Host initiated processing for a B node
+    */
+
+   BEGIN
+        /*
+         * same as for a unique name with the
+         * exception that the group bit (G) must
+         * be set in the request packets.
+         */
+
+        ...
+        G = GROUP;
+        ...
+        ...
+
+        /*
+         * broadcast request ...
+         */
+
+   END
+
+5.1.1.3.  B-NODE FIND_NAME
+
+   PROCEDURE find_name(name)
+
+   /*
+    * Host initiated processing for a B node
+    */
+
+   BEGIN
+
+        REPEAT
+             /*
+              * build packet
+              */
+             ONT = B;
+             TTL = 0;
+             G = DONT CARE;
+
+             broadcast NAME QUERY REQUEST packet;
+
+             /*
+              * a node might send response packet
+              */
+
+             pause(BCAST_REQ_RETRY_TIMEOUT);
+        UNTIL response packet received OR
+             max transmit threshold exceeded
+
+        IF no response packet received THEN
+             return failure;
+        ELSE
+        IF NOT response tid = request tid THEN
+             ignore packet;
+        ELSE
+        CASE packet type OF
+        POSITIVE NAME QUERY RESPONSE:
+             /*
+              * Start a timer to detect conflict.
+              *
+              * Be prepared to detect conflict if
+              * any more response packets are received.
+              *
+              */
+
+             save response as authoritative response;
+             start_timer(CONFLICT_TIMER);
+             return success;
+
+        NEGATIVE NAME QUERY RESPONSE:
+        REDIRECT NAME QUERY RESPONSE:
+
+             /*
+              * B Node should normally not get either
+              * response.
+              */
+
+              ignore response packet;
+
+        END /* case */
+   END /* procedure */
+
+5.1.1.4.  B NODE NAME RELEASE
+
+   PROCEDURE delete_name (name)
+   BEGIN
+
+        REPEAT
+
+             /*
+              * build packet
+              */
+
+             ...
+
+             /*
+              * send request
+              */
+
+             broadcast NAME RELEASE REQUEST packet;
+
+             /*
+              * no response packet expected
+              */
+
+             pause(BCAST_REQ_RETRY_TIMEOUT);
+
+        UNTIL retransmit count has been exceeded
+   END /* procedure */
+
+5.1.1.5.  B-NODE INCOMING PACKET PROCESSING
+
+   Following processing is done when broadcast or unicast packets
+   are received at the NAME_SERVICE_UDP_PORT.
+
+   PROCEDURE process_incoming_packet(packet)
+
+   /*
+    * Processing initiated by incoming packets for a B node
+    */
+
+   BEGIN
+        /*
+         * Note: response packets are always sent
+         * to:
+         * source IP address of request packet
+         * source UDP port of request packet
+         */
+
+        CASE packet type OF
+
+        NAME REGISTRATION REQUEST (UNIQUE):
+             IF name exists in local name table THEN
+                  send NEGATIVE NAME REGISTRATION RESPONSE ;
+        NAME REGISTRATION REQUEST (GROUP):
+             IF name exists in local name table THEN
+             BEGIN
+                  IF local entry is a unique name THEN
+                      send NEGATIVE NAME REGISTRATION RESPONSE ;
+             END
+        NAME QUERY REQUEST:
+             IF name exists in local name table THEN
+             BEGIN
+                  build response packet;
+
+                  send POSITIVE NAME QUERY RESPONSE;
+        POSITIVE NAME QUERY RESPONSE:
+             IF name conflict timer is not active THEN
+             BEGIN
+                  /*
+                   * timer has expired already...  ignore this
+                   * packet
+                   */
+
+                  return;
+             END
+             ELSE /* timer is active */
+             IF a response for this name has previously been
+                  received THEN
+             BEGIN /* existing entry */
+
+                  /*
+                   * we sent out a request packet, and
+                   * have already received (at least)
+                   * one response
+                   *
+                   * Check if conflict exists.
+                   * If so, send out a conflict packet.
+                   *
+                   * Note: detecting conflict does NOT
+                   * affect any existing sessions.
+                   *
+                   */
+
+                  /*
+                   * Check for name conflict.
+                   * See "Name Conflict" in Concepts and Methods
+                   */
+                  check saved authoritative response against
+                       information in this response packet;
+                  IF conflict detected THEN
+                  BEGIN
+                       unicast NAME CONFLICT DEMAND packet;
+                       IF entry exists in cache THEN
+                       BEGIN
+                            remove entry from cache;
+                       END
+                  END
+             END /* existing entry */
+             ELSE
+             BEGIN
+                  /*
+                   * Note: If this was the first response
+                   * to a name query, it would have been
+                   * handled in the
+                   * find_name() procedure.
+
+                   */
+
+                  ignore packet;
+             END
+        NAME CONFLICT DEMAND:
+             IF name exists in local name table THEN
+             BEGIN
+                  mark name as conflict detected;
+
+                  /*
+                   * a name in the state "conflict detected"
+                   * does not "logically" exist on that node.
+                   * No further session will be accepted on
+                   * that name.
+                   * No datagrams can be sent against that name.
+                   * Such an entry will not be used for
+                   * purposes of processing incoming request
+                   * packets.
+                   * The only valid user NetBIOS operation
+                   * against such a name is DELETE NAME.
+                   */
+             END
+        NAME RELEASE REQUEST:
+             IF caching is being done THEN
+             BEGIN
+                  remove entry from cache;
+             END
+        NAME UPDATE REQUEST:
+             IF caching is being done THEN
+             BEGIN
+                  IF entry exists in cache already,
+                       update cache;
+                  ELSE IF name is "interesting" THEN
+                  BEGIN
+                       add entry to cache;
+                  END
+             END
+
+        NODE STATUS REQUEST:
+             IF name exists in local name table THEN
+             BEGIN
+                  /*
+                   * send only those names that are
+                   * in the same scope as the scope
+                   * field in the request packet
+                   */
+
+                  send NODE STATUS RESPONSE;
+             END
+   END
+
+5.1.2.  P-NODE ACTIVITY
+
+   All packets sent or received by P nodes are unicast UDP packets.
+   A P node sends name service requests to the NBNS node that is
+   specified in the P-node configuration.
+
+5.1.2.1.  P-NODE ADD_NAME
+
+   PROCEDURE add_name(newname)
+
+   /*
+    * Host initiated processing for a P node
+    */
+
+   BEGIN
+
+        REPEAT
+             /*
+              * build packet
+              */
+
+             ONT = P;
+             G = UNIQUE;
+             ...
+
+             /*
+              * send request
+              */
+
+             unicast NAME REGISTRATION REQUEST packet;
+
+             /*
+              * NBNS will send response packet
+              */
+
+             IF receive a WACK RESPONSE THEN
+                  pause(time from TTL field of response);
+             ELSE
+                  pause(UCAST_REQ_RETRY_TIMEOUT);
+        UNTIL response packet is received OR
+             retransmit count has been exceeded
+
+        IF no response packet was received THEN
+        BEGIN /* no response */
+             /*
+              * NBNS is down.  Cannot claim name.
+              */
+
+             return failure; /* name cannot be claimed */
+        END /* no response */
+        ELSE
+
+        BEGIN /* response */
+            IF NOT response tid = request tid THEN
+            BEGIN
+             /*  Packet may belong to another transaction  */
+             ignore response packet;
+            END
+            ELSE
+            CASE packet type OF
+
+            POSITIVE NAME REGISTRATION RESPONSE:
+
+                 /*
+                  * name can be added
+                  */
+
+                 adjust refresh timeout value, TTL, for this name;
+                 return success;      /* name can be added */
+
+            NEGATIVE NAME REGISTRATION RESPONSE:
+                 return failure; /* name cannot be added */
+
+            END-NODE CHALLENGE REGISTRATION REQUEST:
+            BEGIN /* end node challenge */
+
+                 /*
+                  * The response packet has in it the
+                  * address of the presumed owner of the
+                  * name.  Challenge that owner.
+                  * If owner either does not
+                  * respond or indicates that he no longer
+                  * owns the name, claim the name.
+                  * Otherwise, the name cannot be claimed.
+                  *
+                  */
+
+                 REPEAT
+                  /*
+                   * build packet
+                   */
+                  ...
+
+                  unicast NAME QUERY REQUEST packet to the
+                       address contained in the END NODE
+                       CHALLENGE RESPONSE packet;
+
+                  /*
+                   * remote node may send response packet
+                   */
+
+                  pause(UCAST_REQ_RETRY_TIMEOUT);
+
+                 UNTIL response packet is received or
+                     retransmit count has been exceeded
+                 IF no response packet is received OR
+                       NEGATIVE NAME QUERY RESPONSE packet
+                       received THEN
+                 BEGIN /* update */
+
+                  /*
+                   * name can be claimed
+                   */
+
+                  REPEAT
+
+                      /*
+                       * build packet
+                       */
+                       ...
+
+                      unicast NAME UPDATE REQUEST to NBNS;
+
+                      /*
+                       * NBNS node will send response packet
+                       */
+
+                      IF receive a WACK RESPONSE THEN
+                            pause(time from TTL field of response);
+                      ELSE
+                            pause(UCAST_REQ_RETRY_TIMEOUT);
+                  UNTIL response packet is received or
+                      retransmit count has been exceeded
+                  IF no response packet received THEN
+                  BEGIN /* no response */
+
+                       /*
+                        * name could not be claimed
+                        */
+
+                       return failure;
+                  END /* no response */
+                  ELSE
+                  CASE packet type OF
+                       POSITIVE NAME REGISTRATION RESPONSE:
+                            /*
+                             * add name
+                             */
+                            return success;
+                       NEGATIVE NAME REGISTRATION RESPONSE:
+
+                            /*
+                             * you lose  ...
+                             */
+
+                            return failure;
+                       END /* case */
+                 END /* update */
+                 ELSE
+
+                 /*
+                  * received a positive response to the "challenge"
+                  * Remote node still has name
+                  */
+
+                  return failure;
+            END /* end node challenge */
+        END /* response */
+   END /* procedure */
+
+5.1.2.2.  P-NODE ADD GROUP NAME
+
+   PROCEDURE add_group_name(newname)
+
+   /*
+    * Host initiated processing for a P node
+    */
+
+   BEGIN
+        /*
+         * same as for a unique name, except that the
+         * request packet must indicate that a
+         * group name claim is being made.
+         */
+
+        ...
+        G = GROUP;
+        ...
+
+        /*
+         * send packet
+         */
+         ...
+
+   END
+
+   5.1.2.3.  P-NODE FIND NAME
+
+   PROCEDURE find_name(name)
+
+   /*
+    * Host initiated processing for a P node
+    */
+
+   BEGIN
+
+        REPEAT
+             /*
+              * build packet
+              */
+
+             ONT = P;
+             G = DONT CARE;
+
+             unicast NAME QUERY REQUEST packet;
+
+             /*
+              * a NBNS node might send response packet
+              */
+
+             IF receive a WACK RESPONSE THEN
+                  pause(time from TTL field of response);
+             ELSE
+                  pause(UCAST_REQ_RETRY_TIMEOUT);
+        UNTIL response packet received OR
+             max transmit threshold exceeded
+
+        IF no response packet received THEN
+             return failure;
+        ELSE
+        IF NOT response tid = request tid THEN
+             ignore packet;
+        ELSE
+        CASE packet type OF
+        POSITIVE NAME QUERY RESPONSE:
+             return success;
+
+        REDIRECT NAME QUERY RESPONSE:
+
+             /*
+              * NBNS node wants this end node
+              * to use some other NBNS node
+              * to resolve the query.
+              */
+
+              repeat query with NBNS address
+                  in the response packet;
+        NEGATIVE NAME QUERY RESPONSE:
+             return failure;
+
+        END /* case */
+   END /* procedure */
+
+5.1.2.4.  P-NODE DELETE_NAME
+
+   PROCEDURE delete_name (name)
+
+   /*
+    * Host initiated processing for a P node
+    */
+
+   BEGIN
+
+        REPEAT
+
+             /*
+              * build packet
+              */
+             ...
+
+             /*
+              * send request
+              */
+
+             unicast NAME RELEASE REQUEST packet;
+             IF receive a WACK RESPONSE THEN
+                  pause(time from TTL field of response);
+             ELSE
+                  pause(UCAST_REQ_RETRY_TIMEOUT);
+        UNTIL retransmit count has been exceeded
+             or response been received
+
+        IF response has been received THEN
+        CASE packet type OF
+        POSITIVE NAME RELEASE RESPONSE:
+             return success;
+        NEGATIVE NAME RELEASE RESPONSE:
+
+             /*
+              * NBNS does want node to delete this
+              * name !!!
+              */
+
+             return failure;
+        END /* case */
+   END /* procedure */
+
+5.1.2.5.  P-NODE INCOMING PACKET PROCESSING
+
+   Processing initiated by reception of packets at a P node
+
+   PROCEDURE process_incoming_packet(packet)
+
+   /*
+    * Processing initiated by incoming packets at a P node
+    */
+
+   BEGIN
+
+        /*
+         * always ignore UDP broadcast packets
+         */
+
+        IF packet was sent as a broadcast THEN
+        BEGIN
+             ignore packet;
+             return;
+        END
+        CASE packet type of
+
+        NAME CONFLICT DEMAND:
+             IF name exists in local name table THEN
+                  mark name as in conflict;
+             return;
+
+        NAME QUERY REQUEST:
+             IF name exists in local name table THEN
+             BEGIN /* name exists */
+
+                  /*
+                   * build packet
+                   */
+                  ...
+
+                  /*
+                   * send response to the IP address and port
+                   * number from which the request was received.
+                   */
+
+                  send POSITIVE NAME QUERY RESPONSE ;
+                  return;
+             END /* exists */
+             ELSE
+             BEGIN /* does not exist */
+
+                  /*
+                   * send response to the requestor
+                   */
+
+                  send NEGATIVE NAME QUERY RESPONSE ;
+                  return;
+             END /* does not exist */
+        NODE STATUS REQUEST:
+             /*
+              * Name of "*" may be used for force node to
+              * divulge status for administrative purposes
+              */
+             IF name in local name table OR name = "*" THEN
+             BEGIN
+                  /*
+
+                   * Build response packet and
+                   * send to requestor node
+                   * Send only those names that are
+                   * in the same scope as the scope
+                   * in the request packet.
+                   */
+
+                  send NODE STATUS RESPONSE;
+             END
+
+        NAME RELEASE REQUEST:
+             /*
+              * This will be received if the NBNS wants to flush the
+              * name from the local name table, or from the local
+              * cache.
+              */
+
+             IF name exists in the local name table THEN
+             BEGIN
+                  delete name from local name table;
+                  inform user that name has been deleted;
+             END
+             ELSE
+                  IF name has been cached locally THEN
+                  BEGIN
+                       remove entry from cache:
+                  END
+
+        END /* case */
+   END /* procedure */
+
+5.1.2.6.  P-NODE TIMER INITIATED PROCESSING
+
+   Processing initiated by timer expiration.
+
+   PROCEDURE timer_expired()
+   /*
+    * Processing initiated by the expiration of a timer on a P node
+    */
+   BEGIN
+        /*
+         * Send a NAME REFRESH REQUEST for each name which the
+         * TTL which has expired.
+         */
+        REPEAT
+             build NAME REFRESH REQUEST packet;
+             REPEAT
+                  send packet to NBNS;
+
+                  IF receive a WACK RESPONSE THEN
+                       pause(time from TTL field of response);
+
+                  ELSE
+                       pause(UCAST_REQ_RETRY_TIMEOUT);
+             UNTIL response packet is received or
+                  retransmit count has been exceeded
+
+             CASE packet type OF
+               POSITIVE NAME REGISTRATION RESPONSE:
+                  /* successfully refreshed */
+                  reset TTL timer for this name;
+
+               NEGATIVE NAME REGISTRATION RESPONSE:
+                  /*
+                   * refused, can't keep name
+                   * assume in conflict
+                   */
+                  mark name as in conflict;
+             END /* case */
+
+        UNTIL request sent for all names for which TTL
+             has expired
+   END /* procedure */
+
+5.1.3.  M-NODE ACTIVITY
+
+   M nodes behavior is similar to that of P nodes with the addition
+   of some B node-like broadcast actions.  M node name service
+   proceeds in two steps:
+
+   1.Use broadcast UDP based name service.  Depending on the
+     operation, goto step 2.
+
+   2.Use directed UDP name service.
+
+   The following code for M nodes is exactly the same as for a P
+   node, with the exception that broadcast operations are done
+   before P type operation is attempted.
+
+   5.1.3.1.  M-NODE ADD NAME
+
+   PROCEDURE add_name(newname)
+
+   /*
+    * Host initiated processing for a M node
+    */
+
+   BEGIN
+
+        /*
+         * check if name exists on the
+         * broadcast area
+         */
+
+        REPEAT
+            /* build packet */
+
+            ....
+            broadcast NAME REGISTRATION REQUEST packet;
+            pause(BCAST_REQ_RETRY_TIMEOUT);
+
+        UNTIL response packet is received or
+             retransmit count has been  exceeded
+
+        IF valid response received THEN
+        BEGIN
+             /* cannot claim name */
+
+             return failure;
+        END
+
+        /*
+         * No objections received within the
+         * broadcast area.
+         * Send request to name server.
+         */
+
+        REPEAT
+             /*
+              * build packet
+              */
+
+             ONT = M;
+             ...
+
+             unicast NAME REGISTRATION REQUEST packet;
+
+             /*
+              * remote NBNS will send response packet
+              */
+
+             IF receive a WACK RESPONSE THEN
+                  pause(time from TTL field of response);
+             ELSE
+                  pause(UCAST_REQ_RETRY_TIMEOUT);
+
+        UNTIL response packet is received or
+             retransmit count has been exceeded
+
+        IF no response packet was received THEN
+        BEGIN /* no response */
+             /*
+              * NBNS is down.  Cannot claim name.
+              */
+
+             return failure; /* name cannot be claimed */
+        END /* no response */
+        ELSE
+        BEGIN /* response */
+            IF NOT response tid = request tid THEN
+            BEGIN
+             ignore response packet;
+            END
+            ELSE
+            CASE packet type OF
+            POSITIVE NAME REGISTRATION RESPONSE:
+
+                 /*
+                  * name can be added
+                  */
+
+                 adjust refresh timeout value, TTL;
+                 return success;      /* name can be added */
+
+            NEGATIVE NAME REGISTRATION RESPONSE:
+                 return failure; /* name cannot be added */
+
+            END-NODE CHALLENGE REGISTRATION REQUEST:
+            BEGIN /* end node challenge */
+
+                 /*
+                  * The response packet has in it the
+                  * address of the presumed owner of the
+                  * name.  Challenge that owner.
+                  * If owner either does not
+                  * respond or indicates that he no longer
+                  * owns the name, claim the name.
+                  * Otherwise, the name cannot be claimed.
+                  *
+                  */
+
+                 REPEAT
+                  /*
+                   * build packet
+                   */
+                  ...
+
+                  /*
+                   * send packet to address contained in the
+                   * response packet
+                   */
+
+                  unicast NAME QUERY REQUEST packet;
+
+                  /*
+                   * remote node may send response packet
+
+                   */
+
+                  pause(UCAST_REQ_RETRY_TIMEOUT);
+
+                 UNTIL response packet is received or
+                     retransmit count has been exceeded
+                 IF no response packet is received THEN
+                 BEGIN /* no response */
+
+                  /*
+                   * name can be claimed
+                   */
+                  REPEAT
+
+                      /*
+                       * build packet
+                       */
+                       ...
+
+                      unicast NAME UPDATE REQUEST to NBNS;
+
+                      /*
+                       * NBNS node will send response packet
+                       */
+
+                      IF receive a WACK RESPONSE THEN
+                            pause(time from TTL field of response);
+                  ELSE
+                       pause(UCAST_REQ_RETRY_TIMEOUT);
+
+                  UNTIL response packet is received or
+                      retransmit count has been exceeded
+                  IF no response packet received THEN
+                  BEGIN /* no response */
+
+                       /*
+                        * name could not be claimed
+                        */
+
+                       return failure;
+                  END /* no response */
+                  ELSE
+                  CASE packet type OF
+                  POSITIVE NAME REGISTRATION RESPONSE:
+                       /*
+                        * add name
+                        */
+
+                       return success;
+                  NEGATIVE NAME REGISTRATION RESPONSE:
+
+                       /*
+                        * you lose  ...
+                        */
+
+                       return failure;
+                  END /* case */
+                 END /* no response */
+                 ELSE
+                 IF NOT response tid = request tid THEN
+                 BEGIN
+                  ignore response packet;
+                 END
+
+                 /*
+                  * received a response to the "challenge"
+                  * packet
+                  */
+
+                 CASE packet type OF
+                 POSITIVE NAME QUERY:
+
+                  /*
+                   * remote node still has name.
+                   */
+
+                  return failure;
+                 NEGATIVE NAME QUERY:
+
+                  /*
+                   * remote node no longer has name
+                   */
+
+                  return success;
+                 END /* case */
+            END /* end node challenge */
+            END /* case */
+        END /* response */
+   END /* procedure */
+
+5.1.3.2.  M-NODE ADD GROUP NAME
+
+   PROCEDURE add_group_name(newname)
+
+   /*
+    * Host initiated processing for a P node
+    */
+
+   BEGIN
+        /*
+         * same as for a unique name, except that the
+         * request packet must indicate that a
+
+         * group name claim is being made.
+         */
+
+        ...
+        G = GROUP;
+        ...
+
+        /*
+         * send packet
+         */
+         ...
+
+   END
+
+5.1.3.3.  M-NODE FIND NAME
+
+   PROCEDURE find_name(name)
+
+   /*
+    * Host initiated processing for a M node
+    */
+
+   BEGIN
+        /*
+         * check if any node on the broadcast
+         * area has the name
+         */
+
+        REPEAT
+             /* build packet */
+             ...
+
+             broadcast NAME QUERY REQUEST packet;
+             pause(BCAST_REQ_RETRY_TIMEOUT);
+        UNTIL response packet received OR
+             max transmit threshold exceeded
+
+        IF valid response received THEN
+        BEGIN
+             save response as authoritative response;
+             start_timer(CONFLICT_TIMER);
+             return success;
+        END
+
+        /*
+         * no valid response on the b'cast segment.
+         * Try the name server.
+         */
+
+        REPEAT
+
+             /*
+              * build packet
+              */
+
+             ONT = M;
+             G = DONT CARE;
+
+             unicast NAME QUERY REQUEST packet to NBNS;
+
+             /*
+              * a NBNS node might send response packet
+              */
+
+             IF receive a WACK RESPONSE THEN
+                  pause(time from TTL field of response);
+             ELSE
+                  pause(UCAST_REQ_RETRY_TIMEOUT);
+        UNTIL response packet received OR
+             max transmit threshold exceeded
+
+        IF no response packet received THEN
+             return failure;
+        ELSE
+        IF NOT response tid = request tid THEN
+             ignore packet;
+        ELSE
+        CASE packet type OF
+        POSITIVE NAME QUERY RESPONSE:
+             return success;
+
+        REDIRECT NAME QUERY RESPONSE:
+
+             /*
+              * NBNS node wants this end node
+              * to use some other NBNS node
+              * to resolve the query.
+              */
+
+              repeat query with NBNS address
+                  in the response packet;
+        NEGATIVE NAME QUERY RESPONSE:
+             return failure;
+
+        END /* case */
+   END /* procedure */
+
+5.1.3.4.  M-NODE DELETE NAME
+
+   PROCEDURE delete_name (name)
+
+   /*
+
+    * Host initiated processing for a P node
+    */
+
+   BEGIN
+        /*
+         * First, delete name on NBNS
+         */
+
+        REPEAT
+
+             /*
+              * build packet
+              */
+             ...
+
+             /*
+              * send request
+              */
+
+             unicast NAME RELEASE REQUEST packet to NBNS;
+
+             IF receive a WACK RESPONSE THEN
+                  pause(time from TTL field of response);
+             ELSE
+                  pause(UCAST_REQ_RETRY_TIMEOUT);
+        UNTIL retransmit count has been exceeded
+             or response been received
+
+        IF response has been received THEN
+        CASE packet type OF
+        POSITIVE NAME RELEASE RESPONSE:
+             /*
+              * Deletion of name on b'cast segment is deferred
+              * until after NBNS has deleted the name
+              */
+
+             REPEAT
+                  /* build packet */
+
+                  ...
+                  broadcast NAME RELEASE REQUEST;
+                  pause(BCAST_REQ_RETRY_TIMEOUT);
+             UNTIL rexmt threshold exceeded
+
+             return success;
+        NEGATIVE NAME RELEASE RESPONSE:
+
+             /*
+              * NBNS does want node to delete this
+              * name
+              */
+
+             return failure;
+        END /* case */
+   END /* procedure */
+
+5.1.3.5.  M-NODE INCOMING PACKET PROCESSING
+
+   Processing initiated by reception of packets at a M node
+
+   PROCEDURE process_incoming_packet(packet)
+
+   /*
+    * Processing initiated by incoming packets at a M node
+    */
+
+   BEGIN
+        CASE packet type of
+
+        NAME CONFLICT DEMAND:
+             IF name exists in local name table THEN
+                  mark name as in conflict;
+             return;
+
+        NAME QUERY REQUEST:
+             IF name exists in local name table THEN
+             BEGIN /* name exists */
+
+                  /*
+                   * build packet
+                   */
+                  ...
+
+                  /*
+                   * send response to the IP address and port
+                   * number from which the request was received.
+                   */
+
+                  send POSITIVE NAME QUERY RESPONSE ;
+                  return;
+             END /* exists */
+             ELSE
+             BEGIN /* does not exist */
+
+                  /*
+                   * send response to the requestor
+                   */
+
+                  IF request NOT broadcast THEN
+                       /*
+                        * Don't send negative responses to
+                        * queries sent by B nodes
+                        */
+
+                       send NEGATIVE NAME QUERY RESPONSE ;
+                  return;
+             END /* does not exist */
+        NODE STATUS REQUEST:
+             BEGIN
+             /*
+              * Name of "*" may be used for force node to
+              * divulge status for administrative purposes
+              */
+             IF name in local name table OR name = "*" THEN
+                  /*
+                   * Build response packet and
+                   * send to requestor node
+                   * Send only those names that are
+                   * in the same scope as the scope
+                   * in the request packet.
+                   */
+
+                  send NODE STATUS RESPONSE;
+             END
+
+        NAME RELEASE REQUEST:
+             /*
+              * This will be received if the NBNS wants to flush the
+              * name from the local name table, or from the local
+              * cache.
+              */
+
+             IF name exists in the local name table THEN
+             BEGIN
+                  delete name from local name table;
+                  inform user that name has been deleted;
+             END
+             ELSE
+                  IF name has been cached locally THEN
+                  BEGIN
+                       remove entry from cache:
+                  END
+
+        NAME REGISTRATION REQUEST (UNIQUE):
+             IF name exists in local name table THEN
+                  send NEGATIVE NAME REGISTRATION RESPONSE ;
+        NAME REGISTRATION REQUEST (GROUP):
+             IF name exists in local name table THEN
+             BEGIN
+                  IF local entry is a unique name THEN
+                      send NEGATIVE NAME REGISTRATION RESPONSE ;
+             END
+        END /* case */
+   END /* procedure */
+
+5.1.3.6.  M-NODE TIMER INITIATED PROCESSING
+
+   Processing initiated by timer expiration:
+
+   PROCEDURE timer_expired()
+   /*
+    * Processing initiated by the expiration of a timer on a M node
+    */
+   BEGIN
+        /*
+         * Send a NAME REFRESH REQUEST for each name which the
+         * TTL which has expired.
+         */
+        REPEAT
+             build NAME REFRESH REQUEST packet;
+             REPEAT
+                  send packet to NBNS;
+
+                  IF receive a WACK RESPONSE THEN
+                       pause(time from TTL field of response);
+                  ELSE
+                       pause(UCAST_REQ_RETRY_TIMEOUT);
+             UNTIL response packet is received or
+                  retransmit count has been exceeded
+
+             CASE packet type OF
+               POSITIVE NAME REGISTRATION RESPONSE:
+                  /* successfully refreshed */
+                  reset TTL timer for this name;
+
+               NEGATIVE NAME REGISTRATION RESPONSE:
+                  /*
+                   * refused, can't keep name
+                   * assume in conflict
+                   */
+                  mark name as in conflict;
+             END /* case */
+
+        UNTIL request sent for all names for which TTL
+             has expired
+   END /* procedure */
+
+5.1.4.  NBNS ACTIVITY
+
+   A NBNS node will receive directed packets from P and M nodes.
+   Reply packets are always sent as directed packets to the source
+   IP address and UDP port number.  Received broadcast packets must
+   be ignored.
+
+5.1.4.1.  NBNS INCOMING PACKET PROCESSING
+
+   PROCEDURE process_incoming_packet(packet)
+
+   /*
+    * Incoming packet processing on a NS node
+    */
+
+   BEGIN
+        IF packet was sent as a broadcast THEN
+        BEGIN
+             discard packet;
+             return;
+        END
+        CASE packet type of
+
+        NAME REGISTRATION REQUEST (UNIQUE):
+             IF unique name exists in data base THEN
+             BEGIN /* unique name exists */
+                  /*
+                   * NBNS node may be a "passive"
+                   * server in that it expects the
+                   * end node to do the challenge
+                   * server.  Such a NBNS node is
+                   * called a "non-secure" server.
+                   * A "secure" server will do the
+                   * challenging before it sends
+                   * back a response packet.
+                   */
+
+                  IF non-secure THEN
+                  BEGIN
+                       /*
+                        * build response packet
+                        */
+                       ...
+
+                       /*
+                        * let end node do the challenge
+                        */
+
+                       send END-NODE CHALLENGE NAME REGISTRATION
+                            RESPONSE;
+                       return;
+                  END
+                  ELSE
+                  /*
+                   * secure server - do the name
+                   * challenge operation
+                   */
+
+                  REPEAT
+                      send NAME QUERY REQUEST;
+                      pause(UCAST_REQ_RETRY_TIMEOUT);
+                  UNTIL response has been received or
+                       retransmit count has been exceeded
+                  IF no response was received THEN
+                  BEGIN
+
+                       /* node down */
+
+                       update data base - remove entry;
+                       update data base - add new entry;
+                       send POSITIVE NAME REGISTRATION RESPONSE;
+                       return;
+                  END
+                  ELSE
+                  BEGIN /* challenged node replied */
+                      /*
+                       * challenged node replied with
+                       * a response packet
+                       */
+
+                      CASE packet type
+
+                      POSITIVE NAME QUERY RESPONSE:
+
+                       /*
+                        * name still owned by the
+                        * challenged node
+                        *
+                        * build packet and send response
+                        */
+                        ...
+
+                       /*
+                        * Note: The NBNS will need to
+                        * keep track (based on transaction id) of
+                        * the IP address and port number
+                        * of the original requestor.
+                        */
+
+                       send NEGATIVE NAME REGISTRATION RESPONSE;
+                       return;
+                      NEGATIVE NAME QUERY RESPONSE:
+
+                       update data base - remove entry;
+                       update data base - add new  entry;
+
+                       /*
+                        * build response packet and send
+
+                        * response
+                        */
+                       send POSITIVE NAME REGISTRATION RESPONSE;
+                       return;
+                      END /* case */
+                  END /* challenged node replied */
+             END /* unique name exists in data base */
+             ELSE
+             IF group name exists in data base THEN
+             BEGIN /* group names exists */
+
+                  /*
+                   * Members of a group name are NOT
+                   * challenged.
+                   * Make the assumption that
+                   * at least some of the group members
+                   * are still alive.
+                   * Refresh mechanism will
+                   * allow the NBNS to detect when all
+                   * members of a group no longer use that
+                   * name
+                   */
+
+                   send NEGATIVE NAME REGISTRATION RESPONSE;
+             END /* group name exists */
+             ELSE
+             BEGIN /* name does not exist */
+
+                  /*
+                   * Name does not exist in data base
+                   *
+                   * This code applies to both non-secure
+                   * and secure server.
+                   */
+
+                  update data base - add new entry;
+                  send POSITIVE NAME REGISTRATION RESPONSE;
+                  return;
+             END
+
+        NAME QUERY REQUEST:
+             IF name exists in data base THEN
+             BEGIN
+                  /*
+                   * build response packet and send to
+                   * requestor
+                   */
+                   ...
+
+                  send POSITIVE NAME QUERY RESPONSE;
+                  return;
+
+             ELSE
+             BEGIN
+                  /*
+                   * build response packet and send to
+                   * requestor
+                   */
+                   ...
+
+                  send NEGATIVE NAME QUERY RESPONSE;
+                  return;
+             END
+
+        NAME REGISTRATION REQUEST (GROUP):
+             IF name exists in data base THEN
+             BEGIN
+                  IF local entry is a unique name THEN
+                  BEGIN /* local is unique */
+
+                      IF non-secure THEN
+                      BEGIN
+                       send  END-NODE CHALLENGE NAME
+                            REGISTRATION RESPONSE;
+                       return;
+                      END
+
+                      REPEAT
+                       send NAME QUERY REQUEST;
+                       pause(UCAST_REQ_RETRY_TIMEOUT);
+                      UNTIL response received or
+                           retransmit count exceeded
+                      IF no response received or
+                           NEGATIVE NAME QUERY RESPONSE
+                            received THEN
+                      BEGIN
+                       update data base - remove entry;
+                       update data base - add new entry;
+                       send POSITIVE NAME REGISTRATION RESPONSE;
+                       return;
+                      END
+                      ELSE
+                      BEGIN
+                       /*
+                        * name still being held
+                        * by challenged node
+                        */
+
+                        send NEGATIVE NAME REGISTRATION RESPONSE;
+                      END
+                  END /* local is unique */
+                  ELSE
+                  BEGIN /* local is group  */
+
+                       /*
+                        * existing entry is a group name
+                        */
+
+                       update data base - remove entry;
+                       update data base - add new entry;
+                       send POSITIVE NAME REGISTRATION RESPONSE;
+                       return;
+                  END /* local is group */
+             END /* names exists */
+             ELSE
+             BEGIN /* does not exist */
+
+                  /* name does not exist in data base */
+
+                  update data base - add new entry;
+                  send POSITIVE NAME REGISTRATION RESPONSE;
+                  return;
+             END /* does not exist */
+
+        NAME RELEASE REQUEST:
+
+             /*
+              * secure server may choose to disallow
+              * a node from deleting a name
+              */
+
+             update data base - remove entry;
+             send POSITIVE NAME RELEASE RESPONSE;
+             return;
+
+        NAME UPDATE REQUEST:
+
+             /*
+              * End-node completed a successful challenge,
+              * no update database
+              */
+
+             IF secure server THEN
+                  send NEGATIVE NAME REGISTRATION RESPONSE;
+             ELSE
+             BEGIN /* new entry */
+                  IF entry already exists THEN
+                       update data base - remove entry;
+                  update data base - add new entry;
+                  send POSITIVE NAME REGISTRATION RESPONSE;
+                  start_timer(TTL);
+             END
+
+        NAME REFRESH REQUEST:
+             check for consistency;
+
+             IF node not allowed to have name THEN
+             BEGIN
+
+                  /*
+                   * tell end node that it can't have name
+                   */
+                  send NEGATIVE NAME REGISTRATION RESPONSE;
+             END
+             ELSE
+             BEGIN
+
+                  /*
+                   * send confirmation response to the
+                   * end node.
+                   */
+                  send POSITIVE NAME REGISTRATION;
+                  start_timer(TTL);
+             END
+             return;
+        END /* case */
+   END /* procedure */
+
+5.1.4.2.  NBNS TIMER INITIATED PROCESSING
+
+   A NS node uses timers to flush out entries from the data base.
+   Each entry in the data base is removed when its timer expires.
+   This time value is a multiple of the refresh TTL established when
+   the name was registered.
+
+   PROCEDURE timer_expired()
+
+   /*
+    * processing initiated by expiration of TTL for a given name
+    */
+
+   BEGIN
+        /*
+         * NBNS can (optionally) ensure
+         * that the node is actually down
+         * by sending a NODE STATUS REQUEST.
+         * If such a request is sent, and
+         * no response is received, it can
+         * be assumed that the node is down.
+         */
+        remove entry from data base;
+   END
+
+5.2.  SESSION SERVICE PROTOCOLS
+
+   The following are variables and should be configurable by the
+   NetBIOS user.  The default values of these variables is found in
+   "Defined Constants and Variables" in the Detailed
+   Specification.):
+
+   - SSN_RETRY_COUNT - The maximum number TCP connection attempts
+     allowable per a single NetBIOS call request.
+
+   - SSN_CLOSE_TIMEOUT is the time period to wait when closing the
+     NetBIOS session before killing the TCP connection if session
+     sends are outstanding.
+
+   The following are Defined Constants for the NetBIOS Session
+   Service.  (See "Defined Constants and Variables" in the Detailed
+   Specification for the value of these constants):
+
+   - SSN_SRVC_TCP_PORT - is the globally well-known TCP port
+     allocated for the NetBIOS Session Service.  The service accepts
+     TCP connections on this port to establish NetBIOS Sessions.
+     The TCP connection established to this port by the caller is
+     initially used for the exchange of NetBIOS control information.
+     The actual NetBIOS data connection may also pass through this
+     port or, through the retargetting facility, through another
+     port.
+
+5.2.1.  SESSION ESTABLISHMENT PROTOCOLS
+
+5.2.1.1.  USER REQUEST PROCESSING
+
+   PROCEDURE listen(listening name, caller name)
+   /*
+    * User initiated processing for B, P and M nodes
+    *
+    * This procedure assumes that an incoming session will be
+    * retargetted here by a session server.
+    */
+   BEGIN
+        Do TCP listen; /* Returns TCP port used */
+        Register listen with Session Service, give names and
+             TCP port;
+
+        Wait for TCP connection to open;   /* Incoming call */
+
+        Read SESSION REQUEST packet from connection
+
+        Process session request (see section on
+             processing initiated by the reception of session
+             service packets);
+
+        Inform Session Service that NetBIOS listen is complete;
+
+        IF session established THEN
+             return success and session information to user;
+        ELSE
+             return failure;
+   END /* procedure */
+
+   PROCEDURE call(calling name, called name)
+   /*
+    * user initiated processing for B, P and M nodes
+    */
+
+   /*
+    * This algorithm assumes that the called name is a unique name.
+    * If the called name is a group name, the call() procedure
+    * needs to cycle through the members of the group
+    * until either (retry_count == SSN_RETRY_COUNT) or
+    * the list has been exhausted.
+    */
+   BEGIN
+        retry_count = 0;
+        retarget = FALSE;   /* TRUE: caller is being retargetted */
+        name_query = TRUE;  /* TRUE: caller must begin again with */
+                            /*       name query. */
+
+        REPEAT
+             IF name_query THEN
+             BEGIN
+                  do name discovery, returns IP address;
+                  TCP port = SSN_SRVC_TCP_PORT;
+
+                  IF name discovery fails THEN
+                       return failure;
+                  ELSE
+                       name_query = FALSE;
+             END
+
+             /*
+              * now have IP address and TCP port of
+              * remote party.
+              */
+
+             establish TCP connection with remote party, use an
+                  ephemeral port as source TCP port;
+             IF connection refused THEN
+             BEGIN
+                  IF retarget THEN
+                  BEGIN
+                       /* retry */
+                       retarget = FALSE;
+
+                       use original IP address and TCP port;
+                       goto LOOP;
+                  END
+
+                  /* retry for just missed TCP listen */
+
+                  pause(SESSION_RETRY_TIMER);
+                  establish TCP connection, again use ephemeral
+                       port as source TCP port;
+
+                  IF connection refused OR
+                     connection timed out THEN
+                       return failure;
+             END
+             ELSE
+             IF connection timed out THEN
+             BEGIN
+                  IF retarget THEN
+                  BEGIN
+                       /* retry */
+                       retarget = FALSE;
+                       use original IP address and TCP port;
+                       goto LOOP;
+                  END
+                  ELSE
+                  BEGIN
+                       /*
+                        * incorrect name discovery was done,
+                        * try again
+                        */
+
+                       inform name discovery process of
+                            possible error;
+                       name_query = TRUE;
+                       goto LOOP;
+                  END
+             END
+
+             /*
+              * TCP connection has been established
+              */
+
+             wait for session response packet;
+             CASE packet type OF
+
+                POSITIVE SESSION RESPONSE:
+                  return success and session established
+                       information;
+
+                NEGATIVE SESSION RESPONSE:
+                BEGIN
+
+                  CASE error OF
+                     NOT LISTENING ON CALLED NAME:
+                     NOT LISTENING FOR CALLING NAME:
+                     BEGIN
+                       kill TCP connection;
+                       return failure;
+                     END
+
+                     CALLED NAME NOT PRESENT:
+                     BEGIN
+                       /*
+                        * called name does not exist on
+                        * remote node
+                        */
+
+                       inform name discovery procedure
+                            of possible error;
+
+                       IF this is a P or M node THEN
+                       BEGIN
+                            /*
+                             * Inform NetBIOS Name Server
+                             * it has returned incorrect
+                             * information.
+                             */
+                            send NAME RELEASE REQUEST for called
+                              name and IP address to
+                              NetBIOS Name Server;
+                       END
+                       /* retry from beginning */
+                       retarget = FALSE;
+                       name_query = TRUE;
+                       goto LOOP;
+                     END /* called name not present */
+                  END /* case */
+                END /* negative response */
+
+                RETARGET SESSION RESPONSE:
+                BEGIN
+                  close TCP connection;
+                  extract IP address and TCP port from
+                       response;
+                  retarget = TRUE;
+                END /* retarget response */
+             END /* case */
+
+   LOOP:          retry_count = retry_count + 1;
+
+        UNTIL (retry_count > SSN_RETRY_COUNT);
+        return failure;
+   END /* procedure */
+
+5.2.1.2.  RECEIVED PACKET PROCESSING
+
+   These are packets received on a TCP connection before a session
+   has been established.  The listen routines attached to a NetBIOS
+   user process need not implement the RETARGET response section.
+   The user process version, separate from a shared Session Service,
+   need only accept (POSITIVE SESSION RESPONSE) or reject (NEGATIVE
+   SESSION RESPONSE) a session request.
+
+   PROCEDURE session_packet(packet)
+   /*
+    * processing initiated by receipt of a session service
+    * packet for a session in the session establishment phase.
+    * Assumes the TCP connection has been accepted.
+    */
+   BEGIN
+        CASE packet type
+
+           SESSION REQUEST:
+           BEGIN
+             IF called name does not exist on node THEN
+             BEGIN
+                  send NEGATIVE SESSION RESPONSE with CALLED
+                       NAME NOT PRESENT error code;
+                  close TCP connection;
+             END
+
+             Search for a listen with CALLING NAME for CALLED
+                  NAME;
+             IF matching listen is found THEN
+             BEGIN
+                  IF port of listener process is port TCP
+                     connection is on THEN
+                  BEGIN
+                       send POSITIVE SESSION RESPONSE;
+
+                       Hand off connection to client process
+                            and/or inform user session is
+                            established;
+                  END
+                  ELSE
+                  BEGIN
+                       send RETARGET SESSION RESPONSE with
+                            listener's IP address and
+                            TCP port;
+                       close TCP connection;
+                  END
+             END
+             ELSE
+             BEGIN
+                  /* no matching listen pending */
+
+                  send NEGATIVE SESSION RESPONSE with either
+                       NOT LISTENING ON CALLED NAME or NOT
+                       LISTENING FOR CALLING NAME error
+                       code;
+                  close TCP connection;
+             END
+           END /* session request */
+        END /* case */
+   END /* procedure */
+
+5.2.2.  SESSION DATA TRANSFER PROTOCOLS
+
+5.2.2.1.  USER REQUEST PROCESSING
+
+   PROCEDURE send_message(user_message)
+   BEGIN
+        build SESSION MESSAGE header;
+        send SESSION MESSAGE header;
+        send user_message;
+        reset and restart keep-alive timer;
+        IF send fails THEN
+        BEGIN
+             /*
+              * TCP connection has failed */
+              */
+             close NetBIOS session;
+             inform user that session is lost;
+             return failure;
+        END
+        ELSE
+             return success;
+   END
+
+   5.2.2.2.  RECEIVED PACKET PROCESSING
+
+   These are packets received after a session has been established.
+
+   PROCEDURE session_packet(packet)
+   /*
+    * processing initiated by receipt of a session service
+    * packet for a session in the data transfer phase.
+    */
+   BEGIN
+        CASE packet type OF
+
+           SESSION  MESSAGE:
+           BEGIN
+             process message header;
+             read in user data;
+             reset and restart keep-alive timer;
+             deliver data to user;
+
+           END /* session message */
+
+           SESSION KEEP ALIVE:
+             discard packet;
+
+        END /* case */
+   END /* procedure */
+
+5.2.2.3.  PROCESSING INITIATED BY TIMER
+
+   PROCEDURE session_ka_timer()
+   /*
+    * processing initiated when session keep alive timer expires
+    */
+   BEGIN
+            send SESSION KEEP ALIVE, if configured;
+            IF send fails THEN
+            BEGIN
+             /* remote node, or path to it, is down */
+
+             abort TCP connection;
+             close NetBIOS session;
+             inform user that session is lost;
+             return;
+            END
+   END /* procedure */
+
+5.2.3.  SESSION TERMINATION PROTOCOLS
+
+5.2.3.1.  USER REQUEST PROCESSING
+
+   PROCEDURE close_session()
+
+   /* initiated by a user request to close a session */
+
+   BEGIN
+        close gracefully the TCP connection;
+
+        WAIT for the connection to close or SSN_CLOSE_TIMEOUT
+             to expire;
+
+        IF time out expired THEN
+             abort TCP connection;
+   END /* procedure */
+
+5.2.3.2.  RECEPTION INDICATION PROCESSING
+
+   PROCEDURE close_indication()
+   /*
+    * initiated by a TCP indication of a close request from
+    * the remote connection partner.
+
+    */
+   BEGIN
+        close gracefully TCP connection;
+
+        close NetBIOS session;
+
+        inform user session closed by remote partner;
+   END /* procedure */
+
+5.3.  NetBIOS DATAGRAM SERVICE PROTOCOLS
+
+   The following are GLOBAL variables and should be NetBIOS user
+   configurable:
+
+   - SCOPE_ID: the non-leaf section of the domain name preceded by a
+     '.'  which represents the domain of the NetBIOS scope for the
+     NetBIOS name.  The following protocol description only supports
+     single scope operation.
+
+   - MAX_DATAGRAM_LENGTH: the maximum length of an IP datagram.  The
+     minimal maximum length defined in for IP is 576 bytes.  This
+     value is used when determining whether to fragment a NetBIOS
+     datagram.  Implementations are expected to be capable of
+     receiving unfragmented NetBIOS datagrams up to their maximum
+     size.
+
+   - BROADCAST_ADDRESS: the IP address B-nodes use to send datagrams
+     with group name destinations and broadcast datagrams.  The
+     default is the IP broadcast address for a single IP network.
+
+   The following are Defined Constants for the NetBIOS Datagram
+   Service:
+
+   - DGM_SRVC_UDP_PORT: the globally well-known UDP port allocated
+     where the NetBIOS Datagram Service receives UDP packets.  See
+     section 6, "Defined Constants", for its value.
+
+5.3.1.  B NODE TRANSMISSION OF NetBIOS DATAGRAMS
+
+   PROCEDURE send_datagram(data, source, destination, broadcast)
+
+   /*
+    * user initiated processing on B node
+    */
+
+   BEGIN
+        group = FALSE;
+
+        do name discovery on destination name, returns name type and
+             IP address;
+
+        IF name type is group name THEN
+        BEGIN
+             group = TRUE;
+        END
+
+        /*
+         * build datagram service UDP packet;
+         */
+        convert source and destination NetBIOS names into
+             half-ASCII, biased encoded name;
+        SOURCE_NAME = cat(source, SCOPE_ID);
+        SOURCE_IP = this nodes IP address;
+        SOURCE_PORT =  DGM_SRVC_UDP_PORT;
+
+        IF NetBIOS broadcast THEN
+        BEGIN
+             DESTINATION_NAME = cat("*", SCOPE_ID)
+        END
+        ELSE
+        BEGIN
+             DESTINATION_NAME = cat(destination, SCOPE_ID)
+        END
+
+        MSG_TYPE = select_one_from_set
+             {BROADCAST, DIRECT_UNIQUE, DIRECT_GROUP}
+        DGM_ID = next transaction id for Datagrams;
+        DGM_LENGTH = length of data + length of second level encoded
+             source and destination names;
+
+        IF (length of the NetBIOS Datagram, including UDP and
+            IP headers, > MAX_DATAGRAM_LENGTH) THEN
+        BEGIN
+             /*
+              * fragment NetBIOS datagram into 2 UDP packets
+              */
+             Put names into 1st UDP packet and any data that fits
+                  after names;
+             Set MORE and FIRST bits in 1st UDP packet's FLAGS;
+             OFFSET in 1st UDP = 0;
+
+             Replicate NetBIOS Datagram header from 1st UDP packet
+                  into 2nd UDP packet;
+             Put rest of data in 2nd UDP packet;
+             Clear MORE and FIRST bits in 2nd UDP packet's FLAGS;
+             OFFSET in 2nd UDP = DGM_LENGTH - number of name and
+                  data bytes in 1st UDP;
+        END
+        BEGIN
+             /*
+              * Only need one UDP packet
+              */
+
+             USER_DATA = data;
+             Clear MORE bit and set FIRST bit in FLAGS;
+             OFFSET = 0;
+        END
+
+        IF (group == TRUE) OR (NetBIOS broadcast) THEN
+        BEGIN
+             send UDP packet(s) to BROADCAST_ADDRESS;
+        END
+        ELSE
+        BEGIN
+             send UDP packet(s) to IP address returned by name
+                discovery;
+        END
+   END /* procedure */
+
+5.3.2.  P AND M NODE TRANSMISSION OF NetBIOS DATAGRAMS
+
+   PROCEDURE send_datagram(data, source, destination, broadcast)
+
+   /*
+    * User initiated processing on P and M node.
+    *
+    * This processing is the same as for B nodes except for
+    * sending broadcast and multicast NetBIOS datagrams.
+    */
+
+   BEGIN
+        group = FALSE;
+
+        do name discovery on destination name, returns name type
+             and IP address;
+        IF name type is group name THEN
+        BEGIN
+             group = TRUE;
+        END
+
+        /*
+         * build datagram service UDP packet;
+         */
+        convert source and destination NetBIOS names into
+             half-ASCII, biased encoded name;
+        SOURCE_NAME = cat(source, SCOPE_ID);
+        SOURCE_IP = this nodes IP address;
+        SOURCE_PORT =  DGM_SRVC_UDP_PORT;
+
+        IF NetBIOS broadcast THEN
+        BEGIN
+             DESTINATION_NAME = cat("*", SCOPE_ID)
+        END
+        ELSE
+
+        BEGIN
+             DESTINATION_NAME = cat(destination, SCOPE_ID)
+        END
+
+        MSG_TYPE = select_one_from_set
+             {BROADCAST, DIRECT_UNIQUE, DIRECT_GROUP}
+        DGM_ID = next transaction id for Datagrams;
+        DGM_LENGTH = length of data + length of second level encoded
+             source and destination names;
+
+        IF (length of the NetBIOS Datagram, including UDP and
+            IP headers, > MAX_DATAGRAM_LENGTH) THEN
+        BEGIN
+             /*
+              * fragment NetBIOS datagram into 2 UDP packets
+              */
+             Put names into 1st UDP packet and any data that fits
+                  after names;
+             Set MORE and FIRST bits in 1st UDP packet's FLAGS;
+
+             OFFSET in 1st UDP = 0;
+
+             Replicate NetBIOS Datagram header from 1st UDP packet
+                  into 2nd UDP packet;
+             Put rest of data in 2nd UDP packet;
+             Clear MORE and FIRST bits in 2nd UDP packet's FLAGS;
+             OFFSET in 2nd UDP = DGM_LENGTH - number of name and
+                  data bytes in 1st UDP;
+        END
+        BEGIN
+             /*
+              * Only need one UDP packet
+              */
+             USER_DATA = data;
+             Clear MORE bit and set FIRST bit in FLAGS;
+             OFFSET = 0;
+        END
+
+        IF (group == TRUE) OR (NetBIOS broadcast) THEN
+        BEGIN
+             /*
+              * Sending of following query is optional.
+              * Node may send datagram to NBDD immediately
+              * but NBDD may discard the datagram.
+              */
+             send DATAGRAM QUERY REQUEST to NBDD;
+             IF response is POSITIVE QUERY RESPONSE THEN
+                  send UDP packet(s) to NBDD Server IP address;
+             ELSE
+             BEGIN
+                  get list of destination nodes from NBNS;
+
+                  FOR EACH node in list
+                  BEGIN
+                       send UDP packet(s) to this node's
+                            IP address;
+                  END
+             END
+        END
+        ELSE
+        BEGIN
+             send UDP packet(s) to IP address returned by name
+                discovery;
+   END /* procedure */
+
+5.3.3.  RECEPTION OF NetBIOS DATAGRAMS BY ALL NODES
+
+   The following algorithm discards out of order NetBIOS Datagram
+   fragments.  An implementation which reassembles out of order
+   NetBIOS Datagram fragments conforms to this specification.  The
+   fragment discard timer is initialized to the value FRAGMENT_TO.
+   This value should be user configurable.  The default value is
+   given in Section 6, "Defined Constants and Variables".
+
+   PROCEDURE datagram_packet(packet)
+
+   /*
+    * processing initiated by datagram packet reception
+    * on B, P and M nodes
+    */
+   BEGIN
+        /*
+         * if this node is a P node, ignore
+         * broadcast packets.
+         */
+
+        IF this is a P node AND incoming packet is
+             a broadcast packet THEN
+        BEGIN
+             discard packet;
+        END
+
+        CASE packet type OF
+
+           DATAGRAM SERVICE:
+           BEGIN
+             IF FIRST bit in FLAGS is set THEN
+             BEGIN
+                  IF MORE bit in FLAGS is set THEN
+                  BEGIN
+                       Save 1st UDP packet of the Datagram;
+                       Set this Datagram's fragment discard
+                         timer to FRAGMENT_TO;
+
+                       return;
+                  END
+                  ELSE
+                       Datagram is composed of a single
+                         UDP packet;
+             END
+             ELSE
+             BEGIN
+                  /* Have the second fragment of a Datagram */
+
+                  Search for 1st fragment by source IP address
+                     and DGM_ID;
+                  IF found 1st fragment THEN
+                       Process both UDP packets;
+                  ELSE
+                  BEGIN
+                       discard 2nd fragment UDP packet;
+                       return;
+                  END
+             END
+
+             IF DESTINATION_NAME is '*' THEN
+             BEGIN
+                  /* NetBIOS broadcast */
+
+                  deliver USER_DATA from UDP packet(s) to all
+                       outstanding receive broadcast
+                       datagram requests;
+                  return;
+             END
+             ELSE
+             BEGIN /* non-broadcast */
+                  /* Datagram for Unique or Group Name */
+
+                  IF DESTINATION_NAME is not present in the
+                     local name table THEN
+                  BEGIN
+                       /* destination not present */
+                       build DATAGRAM ERROR packet, clear
+                            FIRST and MORE bit, put in
+                            this nodes IP and PORT, set
+                            ERROR_CODE;
+                       send DATAGRAM ERROR packet to
+                            source IP address and port
+                            of UDP;
+                       discard UDP packet(s);
+                       return;
+                  END
+                  ELSE
+                  BEGIN /* good */
+                       /*
+
+                        * Replicate received NetBIOS datagram for
+                        * each recipient
+                        */
+                       FOR EACH pending NetBIOS user's receive
+                            datagram operation
+                       BEGIN
+                            IF source name of operation
+                               matches destination name
+                               of packet THEN
+                            BEGIN
+                               deliver USER_DATA from UDP
+                                 packet(s);
+                            END
+                       END /* for each */
+                       return;
+                  END /* good */
+             END /* non-broadcast */
+            END /* datagram service */
+
+           DATAGRAM ERROR:
+           BEGIN
+                /*
+                 * name service returned incorrect information
+                 */
+
+                inform local name service that incorrect
+                  information was provided;
+
+                IF this is a P or M node THEN
+                BEGIN
+                     /*
+                      * tell NetBIOS Name Server that it may
+                      * have given incorrect information
+                      */
+
+                     send NAME RELEASE REQUEST with name
+                       and incorrect IP address to NetBIOS
+                       Name Server;
+                END
+           END /* datagram error */
+
+        END /* case */
+   END
+
+5.3.4.  PROTOCOLS FOR THE NBDD
+
+   The key to NetBIOS Datagram forwarding service is the packet
+   delivered to the destination end node must have the same NetBIOS
+   header as if the source end node sent the packet directly to the
+   destination end node.  Consequently, the NBDD does not reassemble
+   NetBIOS Datagrams.  It forwards the UDP packet as is.
+
+   PROCEDURE  datagram_packet(packet)
+
+   /*
+    * processing initiated by a incoming datagram service
+    * packet on a NBDD node.
+    */
+
+   BEGIN
+        CASE packet type OF
+
+           DATAGRAM SERVICE:
+           BEGIN
+                IF packet was sent as a directed
+                   NetBIOS datagram THEN
+                BEGIN
+                  /*
+                   * provide group forwarding service
+                   *
+                   * Forward datagram to each member of the
+                   * group.  Can forward via:
+                   *   1) get list of group members and send
+                   *   the DATAGRAM SERVICE packet unicast
+                   *   to each
+                   *   2) use Group Multicast, if available
+                   *   3) combination of 1) and 2)
+                   */
+
+                  ...
+
+                END
+
+                ELSE
+                BEGIN
+                  /*
+                   * provide broadcast forwarding service
+                   *
+                   * Forward datagram to every node in the
+                   * NetBIOS scope.  Can forward via:
+                   *   1) get list of group members and send
+                   *   the DATAGRAM SERVICE packet unicast
+                   *   to each
+                   *   2) use Group Multicast, if available
+                   *   3) combination of 1) and 2)
+                   */
+
+                  ...
+
+                END
+           END /* datagram service */
+
+           DATAGRAM ERROR:
+
+           BEGIN
+             /*
+              * Should never receive these because Datagrams
+              * forwarded have source end node IP address and
+              * port in NetBIOS header.
+              */
+
+             send DELETE NAME REQUEST with incorrect name and
+                  IP address to NetBIOS Name Server;
+
+           END /* datagram error */
+
+           DATAGRAM QUERY REQUEST:
+           BEGIN
+             IF can send packet to DESTINATION_NAME THEN
+             BEGIN
+                  /*
+                   * NBDD is able to relay Datagrams for
+                   * this name
+                   */
+
+                  send POSITIVE DATAGRAM QUERY RESPONSE to
+                    REQUEST source IP address and UDP port
+                    with request's DGM_ID;
+             END
+             ELSE
+             BEGIN
+                  /*
+                   * NBDD is NOT able to relay Datagrams for
+                   * this name
+                   */
+
+                  send NEGATIVE DATAGRAM QUERY RESPONSE to
+                    REQUEST source IP address and UDP port
+
+                    with request's DGM_ID;
+             END
+           END /* datagram query request */
+
+        END /* case */
+   END /* procedure */
+
+6.  DEFINED CONSTANTS AND VARIABLES
+
+   GENERAL:
+
+      SCOPE_ID                   The name of the NetBIOS scope.
+
+                                 This is expressed as a character
+                                 string meeting the requirements of
+                                 the domain name system and without
+                                 a leading or trailing "dot".
+
+                                 An implementation may elect to make
+                                 this a single global value for the
+                                 node or allow it to be specified
+                                 with each separate NetBIOS name
+                                 (thus permitting cross-scope
+                                 references.)
+
+      BROADCAST_ADDRESS          An IP address composed of the
+                                 nodes's network and subnetwork
+                                 numbers with all remaining bits set
+                                 to one.
+
+                                 I.e. "Specific subnet" broadcast
+                                 addressing according to section 2.3
+                                 of RFC 950.
+
+      BCAST_REQ_RETRY_TIMEOUT    250 milliseconds.
+                                 An adaptive timer may be used.
+
+      BCAST_REQ_RETRY_COUNT      3
+
+      UCAST_REQ_RETRY_TIMEOUT    5 seconds
+                                 An adaptive timer may be used.
+
+      UCAST_REQ_RETRY_COUNT      3
+
+      MAX_DATAGRAM_LENGTH        576 bytes (default)
+
+   NAME SERVICE:
+
+      REFRESH_TIMER              Negotiated with NBNS for each name.
+
+      CONFLICT_TIMER             1 second
+                                 Implementations may chose a longer
+                                 value.
+
+      NAME_SERVICE_TCP_PORT      137 (decimal)
+
+      NAME_SERVICE_UDP_PORT      137 (decimal)
+
+      INFINITE_TTL               0
+
+   SESSION SERVICE:
+
+      SSN_SRVC_TCP_PORT          139 (decimal)
+
+      SSN_RETRY_COUNT            4 (default)
+                                 Re-configurable by user.
+
+      SSN_CLOSE_TIMEOUT          30 seconds (default)
+                                 Re-configurable by user.
+
+      SSN_KEEP_ALIVE_TIMEOUT     60 seconds, recommended, may be set to
+                                 a higher value.
+                                 (Session keep-alives are used only
+                                 if configured.)
+
+   DATAGRAM SERVICE:
+
+      DGM_SRVC_UDP_PORT          138 (decimal)
+
+      FRAGMENT_TO                2 seconds (default)
+
+REFERENCES
+
+   [1]  "Protocol Standard For a NetBIOS Service on a TCP/UDP
+        Transport: Concepts and Methods", RFC 1001, March 1987.
+
+   [2]  J. Reynolds, J. Postel, "Assigned Numbers", RFC 990, November
+        1986.
+
+   [3]  P. Mockapetris, "Domain Names - Implementation and
+        Specification", RFC 883, November 1983.
+
+
+


+
+ +
+

Previous: RFC 1001 - Protocol standard for a NetBIOS service on a TCP/UDP transport: Concepts and methods +

  +

Next: RFC 1003 - Issues in defining an equations representation standard +

 

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