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Table 3.2. IPX Encapsulation Schemes
Media Type Encapsulation Scheme Frame Type
Ethernet Novell 802.3 RAW
ARPA DEC Ethernet v2
802.3 IEEE 802.3 Standard
SNAP Ethernet SNAP
Token Ring IEEE 802.5 (802.2 LLC) IEEE 802.5 Standard
SNAP IEEE 802.5 SNAP
FDDI SNAP FDDI SNAP
SAP FDDI 802.2 LLC
Novell ANSI FDDI RAW
Serial IPXWAN PPP
IPXWAN HDLC
Characteristics of different IPX encapsulation schemes include the following:
• Novell RAW uses the standard protocol frame without 802.2 logical link
control.
• Ethernet version 2 is the standard pre-IEEE 3COM/DEC Ethernet version 2
standard frame specification.
• SNAP uses the 802.2 LLC frame format and the protocol type field.
• IEEE 802.* uses the IEEE 802.x standard frame format.
• IPXWAN is a WAN-specific protocol used for IPX routing (and transporting)
communication between routers connected over dedicated serial lines.
For compatibility and, as it turns out, increased flexibility, IPX can support multiple
network segments using different encapsulation schemes over the same physical
(Layer 1) medium. If no router is in place, none of the networks can exchange data
between one another. This is because each network is using a specific frame type.
Only end-nodes that are configured to process the same frame type can exchange
information.
NOTE
This same result occurs when AppleTalk Phase 1 Ethernet and Phase 2 Ethernet are
used on the same media. Because the frame types are different, they can only be
understood by like end-nodes (Phase 1 or Phase 2) but are unable to
cross-communicate.