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Answers to the Chapter 5 Q&A Section 743
59
How many Novell encapsulation types are valid in the IOS for Ethernet interfaces? What
about for FDDI and Token Ring?
There are four encapsulations for Ethernet, three encapsulations for FDDI, and two
encapsulations for Token Ring. Table 5-32 and Table 5-33, on pages 301 and 302, list the
different encapsulations.
60
A router is attached to an Ethernet LAN. Some clients on the LAN use Novell's Ethernet_II
encapsulation, and some use Ethernet_802.3. If the only subcommand on Ethernet0 reads
ipx network 1, which of the clients are working? (All, Ethernet_II, or Ethernet_802.3?)
Just those with Ethernet_802.3 are working. The associated IOS keyword is novell-ether,
and this is the default IPX encapsulation. This question is just trying to test your recall of
the default encapsulation for Ethernet.
61
A router is attached to an Ethernet LAN. Some clients on the LAN use Novell's
Ethernet_802.2 encapsulation, and some use Ethernet_SNAP. Create a configuration that
allows both types of clients to send and receive packets through this router.
interface ethernet 0
ipx network 1 encapsulation sap
ipx network 2 encapsulation snap secondary
Subinterfaces could also have been used instead of secondary IPX networks.
62
True or false: Up to 64 IPX networks can be used on the same Ethernet by using the IPX
secondary address feature. If true, describe the largest number that is practically needed.
If false, what is the maximum number that is legal on an Ethernet?
False. Only one network per encapsulation is allowed. Because four Ethernet
encapsulations can be used with IPX, four IPX networks are supported. Using the same
logic, only three networks are allowed on FDDI, and two on Token Ring.
63
In the ipx network 11 interface subcommand, does the IOS assume that 11 is binary, octal,
decimal, or hexadecimal? What is the largest valid value that could be configured instead
of 11?
All IPX network numbers are considered to be hexadecimal by the IOS. The largest value
is FFFFFFFE, with FFFFFFFF being reserved as the broadcast network.
64
What IOS IPX encapsulation keyword implies use of an 802.2 header but no SNAP
header? On what types of interfaces is this type of encapsulation valid?
SAP encapsulation on the IOS implies use of the 802.2 header immediately before the IPX
packet. SAP and SNAP are valid on Ethernet, FDDI, and Token Ring. SAP also refers to
the field in the 802.2 header that is used to identify IPX as the type of packet that follows
the 802.2 header.
apA.fm Page 743 Monday, March 20, 2000 5:24 PM