The NetBIOS interface was developed by Sytec Inc. (which became Hughes LAN Systems, then Whittaker Communications) for International Business Machines Corporation (IBM) in 1983. This operated over proprietary Sytec protocols on IBM's PC Network. Information is provided here for reference although these protocols have now been superseded by the NetBIOS Frames protocol running over Token Ring or Ethernet etc.

In the IBM PC Network name management is performed by the Name Management Protocol which consists of the following packet types: Name Claim / Name Cancel Packet A single octet indicates whether the packet is used to claim a name (value 0x10) or release a name (value 0xA0) Name Claim Response Packet This packet is used to indicate that the name is already in use. Details of packet structures for Name Management in IBM PC Networks are given in the

From "Inside NetBIOS": Name Claim / Name Cancel Packet: Field Length Description Start 1 Start Deliminator value 0x7E Destination 6 Destination Address Source 6 Source Address Length 2 Length of packet value 2 value set to 0x5000 Function 1 10h for Name Claim, 0xA0 for Cancel Accept 1 Number of packets willing to accept Connection id 2 Connection id value 2 value set to 0x0202 Undefined 2 value of two octets undefined value 2 value set to 0x0400 Undefined 4 value of four octets undefined value 2 value of 0x10XX value 4 value of 0x0000 Dest Name 16 ASCII Destination NetBIOS name Dest Node Connection id 2 Destination node connection id CRC 4 Cyclic Redundancy Check End of Frame 1 End of frame marker value of 0x7E

Name Claim Response Packet: Field Length Description Start 1 Start Deliminator value 0x7E Destination 6 Destination Address Source 1 Source Address Length 2 Length of packet value 2 value set to 0x4000 value 1 value set to 0x30 Accept 1 Number of packets willing to accept Connection id 2 Connection id Undefined 2 value of two octets undefined Reason packet NAK 1 Reason why packet not acknowledged Undefined 1 value of octet undefined value 2 value set to 0x0400 Undefined 4 value of four octets undefined value 2 value of 0x10XX value 4 value of 0x0000 Dest Name 16 ASCII Destination NetBIOS name Destination node connection id 2 Destination node connection id CRC 4 Cyclic Redundancy Check End of Frame 1 End of frame marker value of 0x7E

Details of packet structures for User Datagram Protocol in IBM PC Networks are given in the

From "Inside NetBIOS": User Datagram Protocol Packet: Field Length Description Start 1 Start Deliminator value 0x7E Destination 6 Destination Address Source 6 Source Address Length 2 Length of packet value 2 value set to 0x5100 value 2 value set to 0x0100 value 2 value set to 0x0001 value 2 value set to 0x1010 value 2 value set to 0x0000 Source Name 16 ASCII Source NetBIOS name Dest Name 16 ASCII Destination NetBIOS name Data variable data Retransmit Count 2 Retransmition Count Source Node Connection id 2 Source Node Connection id Destination id 6 Destination id Source id 6 Source id Prev Node id 6 Previous Node id CRC 4 Cyclic Redundancy Check End of Frame 1 End of frame marker value of 0x7E

Details of packet structures for NetBIOS Session Management in IBM PC Networks are given in the

From "Inside NetBIOS": Session Request Packet : Field Length Description Start 1 Start Deliminator value 0x7E Destination 6 Destination Address Source 6 Source Address Length 2 Length of packet value 2 value set to 0x0040 Function 1 value 0x00-0x07=No poll 0x80-0x0F=Send Return Pkt Accept 1 Number of packets willing to accept Connection id 2 Connection id Sess seq no 1 Sess seq no ACK Seq No 1 ACK Seq No value 2 value set to 0x0001 Response packet size 2 Response packet size value 4 value of 0x0000 value 4 value of 0x1010 Source Name 16 ASCII Source NetBIOS name Dest Name 16 ASCII Destination NetBIOS name Dest Connection id 2 Dest Connection id CRC 4 Cyclic Redundancy Check End of Frame 1 End of frame marker value of 0x7E

Name Claim / Cancel Name Response < - 1 Octet (8 bits) -> < - 1 Octet (8 bits) -> Start Deliminator = 0x7E Start Deliminator = 0x7E Destination Address 6 octets Destination Address 6 octets Source Address 6 octets Source Address 6 octets Length 2 octets Length 2 octets Value 0x5000 Value 0x4000 Claim 0x10 Cancel 0xA0 Value 0x30 No Packets to accept N No Packets to accept N Connection id 2 octets Connection id 2 octets Value 0x02 Undefined Value 0x02 Undefined Undefined Reason NAK Undefined Undefined Value 0x04 Value 0x04 Value 0x00 Value 0x00 Undefined 4 octets Undefined 4 octets Value 0x10 Value 10h Value XXh Value XXh Value 0x00 Value 0x00 Value 0x00 Value 0x00 ASCII Dest name 16 octets ASCII Dest name 16 octets Prev net con id Dest node conn id Prev net con id Dest node conn id Retransmit count CRC 4 octets Retransmit count Source node con id Source node con id Dest id 6 octets EOF 0x7E Source id 6 octets Prev node id 6 octets CRC 4 octets EOF 0x7E Name Query Session Request Session Accept Session Acknowledgment < - 1 Octet (8 bits) -> < - 1 Octet (8 bits) -> <- 1 Octet (8 bits) -> < - 1 Octet (8 bits) -> < - 1 Octet (8 bits) -> Start Deliminator = 0x7E Start Deliminator = 0x7E Start Deliminator = 0x7E Start Deliminator = 0x7E Start Deliminator = 0x7E Destination Address 6 octets Destination Address 6 octets Destination Address 6 octets Destination Address 6 octets Destination Address 6 octets Source Address 6 octets Source Address 6 octets Source Address 6 octets Source Address 6 octets Source Address 6 octets Length 2 octets Length 2 octets Length 2 octets Length 2 octets Length 2 octets Value 0x5000 Value 0x0040 Value 0x0040 Value 0x4000 Value 0x4000 Value 0x10 0x00 - 0x07 No Poll 0x80 -0x0F Send return packet 0x00 - 0x07 No Poll 0x80 -0x0F Send return packet 0x00 - 0x07 No Poll 0x80 -0x0F Send return packet 0x40 - 0x47 No Poll 0x48 -0x4F Send return packet No Packets to accept 0?h No Packets to accept 0?h No Packets to accept 0?h No Packets to accept 0?h No Packets to accept N Connection id 2 octets Connection id 2 octets Connection id 2 octets Connection id 2 octets Connection id 2 octets Value 0x02 Ses Seq No Ses Seq No Ses Seq No Ses Seq No Value 0x02 ACK Seq No ACK Seq No ACK Seq No ACK Seq No Undefined Value 0x00 Value 0x00 0x80-0xF0 End message Undefined Undefined Value 0x01 Value 0x02 DATA N octets Dest Node Con Value 0x10 Response packet size Response packet size Dest Node Con Value 0x00 Response packet size Response packet size CRC 4 octets Undefined Value 0x00 Dest node conn id Undefined Value 0x00 Dest node conn id Undefined Value 0x10 CRC 4 octets Undefined Value 0x10 EOF 0x7E Value 0x10 ASCII Source name Value 0xXX ASCII Source name Value 0xXX ASCII Source name EOF 7Eh Value 0x10 ASCII Source name ASCII Dest name ASCII Source name ASCII Dest name ASCII Source name ASCII Dest name ASCII Source name ASCII Dest name ASCII Source name ASCII Dest name ASCII Source name ASCII Dest name ASCII Source name Dest node con id ASCII Dest name ASCII Source name ASCII Dest name ASCII Source name CRC 4 octets ASCII Dest name ASCII Source name ASCII Dest name ASCII Source name ASCII Dest name ASCII Source name ASCII Dest name ASCII Source name EOF 0x7E ASCII Dest name ASCII Dest name ASCII Dest name ASCII Dest name ASCII Dest name ASCII Dest name ASCII Dest name ASCII Dest name Prev net con id ASCII Dest name Prev net con id ASCII Dest name Retransmit count ASCII Dest name Retransmit count ASCII Dest name Source node con id ASCII Dest name Source node con id ASCII Dest name Dest id ASCII Dest name Dest id ASCII Dest name Dest id ASCII Dest name Dest id ASCII Dest name Dest id ASCII Dest name Dest id ASCII Dest name Source id Dest node conn id Source id CRC Source id CRC Source id CRC Source id CRC Source id EOF 0x7E Prev node id Prev node id Prev node id Prev node id Prev node id Prev node id CRC CRC CRC CRC EOF 0x7E