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302 Chapter 5: Network Protocols
The key for remembering the Novell encapsulation names is that each name refers to the header
that directly precedes the IPX packet. This can help you recall header formats as well.
Remembering the names in the order in this book can also help because the size of the headers
increases with the third and fourth options, as compared with the first two options (see Figure
5-35).
The same encapsulation issue exists on Token Ring and FDDI interfaces. Table 5-33 outlines
the options.
One or more encapsulations are needed per Ethernet interface. If all NetWare clients/servers on
the Ethernet use the same encapsulation, just that single encapsulation is needed. However, if
more than one encapsulation is used, then multiple encapsulations are needed on the router. To
configure multiple encapsulations in the IOS, multiple IPX network numbers must be used on
the same Ethernet, one per encapsulation.
Two methods of configuration can be used to create two IPX networks on the same link. The
first method uses IPX secondary addresses, and the other uses subinterfaces. Both require one
IPX network number per encapsulation type per physical interface. Both methods cause the
same protocol flows to occur. The subinterface style of configuration allows the use of NLSP,
whereas secondary interface configuration does not. (Sample configurations are shown in the
next section of this chapter.)
Table 5-33
IPX Token Ring and FDDI Encapsulations
Novell's Name
Cisco IOS's Name
Description and Hints for Remembering
FDDI_Raw
Novell-fddi
The IPX packet follows directly after the FDDI
header. No Type field of any kind is used.
FDDI_802.2
SAP
The IPX packet follows the 802.2 header. Novell's
name refers to the committee and complete header
that defines the SAP field; Cisco's name refers to the
SAP part of the 802.2 header.
FDDI_SNAP
SNAP
Novell's name refers to the final header before the
IPX header, in this case. Cisco's name refers to this
same header.
Token-Ring
SAP
The IPX packet follows the 802.2 header. Novell's
name refers to the committee and complete header
that defines the SAP field; Cisco's name refers to the
SAP part of the 802.2 header.
Token-Ring_SNAP
SNAP
Novell's name refers to the final header before the
IPX header. Cisco's name refers to this same header.
ch05.fm Page 302 Monday, March 20, 2000 5:06 PM