| NetBIOS, NetBEUI, NBF, NBT, NBIPX, SMB, CIFS Networking: NetBIOS to CIFS | ||
|---|---|---|
| <<< Previous | Supporting Technology, 802.2, Ethernet and Token Ring | Next >>> |
A full description of Ethernet is beyond the scope of this document; some basic information on Ethernet and its use with NetBIOS is given below.
Ethernet is widely used today and well documented. Four types of Ethernet frames have been in common use. For convenience the notation used by Novell is used to describe the four Ethernet frame types:
Known as Ethernet 802.3 raw, this frame type is used in NetWare networks and was the default type in NetWare v2.x and v3.x
Known as Ethernet DIX (Developed by Digital Intel Xerox)
IEEE Ethernet
SNAP (Sub-Network Access Protocol) derived from the Ethernet 802.2 structure
Known as Ethernet 802.3 raw, this frame type is used in NetWare networks and was the default type in NetWare v2.x and v3.x Because of the nature of these frames they are unlikely to carry NBF frames, unless encapsulated in IPX.
NBF frames are found in Ethernet_802.2 frames more than in other Ethernet frames when NBF is implemented "on the wire" rather than encapsulated.
Ethernet_802.2 frames are also used with IPX/SPX and FTAM (File Transfer Access and Management) protocol.
Table 3. Ethernet_802.2 Frame Structure
| Ethernet frame | 802.2 Frame detail | NBF frame |
|---|---|---|
| Preamble 7 octets | ||
| Start frame deliminator 1 octet | ||
| Destination Address 6 octets | ||
| Source Address 6 octets | ||
| Length 2 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 4 octets |
Ethernet_SNAP frames are used by IPX/SPX, TCP/IP and AppleTalk Phase II.
Table 4. Ethernet_SNAP Frame Structure
| Preamble 7 octets |
| Start frame deliminator 1 octet |
| Destination Address 6 octets |
| Source Address 6 octets |
| Length 2 octets |
| DSAP 2 octets value AA |
| SSAP 2 octets value AA |
| Control 1 octets |
| Organizational code 3 octets |
| Ethernet Type 2 octets |
| Data 46-1500 octets |
| Frame Check sequence 4 octets |
Ethernet_II frames are used with IPX/SPX TCP/IP AppleTalk Phase I
Following the source address, is an Ethernet frame type. Information on Ethernet frame types can be found at: http://www.iana.org/assignments/ethernet-numbers and at: http://www.cavebear.com/CaveBear/Ethernet/type.html
For SNA (Systems Network Architecture) communications the value registered for the type is 0x80D5. This value of 0x80D5 is also used for other systems using the IEEE 802.2 API including NetBIOS
Many manuals and documents describe Ethernet in detail including Novell's Guide to NetWare LAN Analysis, see Bibliography
| <<< Previous | Home | Next >>> |
| Token Ring | Up | Encapsulation in TCP/IP |