When IBM introduced Token-Ring, an emulator for NetBIOS was produced. The NetBIOS Extended User Interface (NetBEUI) was introduced in 1985. NetBIOS was no longer implemented only on a set of propriety protocols, but also on 802.2 frames. The implementation on Token-Ring was the first implementation over 802.2 and provides a reference model. Detailed information can be found in the IBM manual: IBM LAN Technical Reference IEEE 802.2 and NetBIOS Application Program Interfaces
A full description of Token Ring is beyond the scope of this document; some basic information on Token Ring and it's use with NetBIOS is given below.
There are two kinds of Token Ring frames: Media Access Control (MAC) frames and Non-MAC frames. MAC frames carry Token Ring management information between nodes, Non-MAC frames carry user data. The non-MAC frames contain IEEE 802.2 Logical Link Control frames which in turn can contain NetBIOS frames.
| Token Ring frame | 802.2 Frame detail | NBF frame |
|---|---|---|
| Start Delimiter (SDEL) 1 octet | ||
| Access Control (AC) 1 octet | ||
| Frame Control (FC) 1 octet | ||
| Destination Address 6 octets | ||
| Source Address 6 octets | ||
| IEEE 802.2 Logical Link Control | DSAP 2 octets | |
| SSAP 2 octets | ||
| Control 1 or 2 octets | ||
| Data 46-1500 octets | NetBIOS header | |
| Optional data | ||
| Frame Check sequence (FCS) 4 octets | ||
| End Delimiter (EDEL) 1 octet | ||
| Frame Status (FS) Check sequence 1 octet |
Many manuals and documents describe Token-Ring in detail including
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