752 Appendix A: Answers to the "Do I Know This Already?" Quizzes and Q&A Sections
23
Must IGRP metrics for multiple routes to the same subnet be exactly equal for the multiple
routes to be added to the routing table? If not, how close in value do the metrics have
to be?
IGRP (and EIGRP) use a concept called variance, which represents how close the metrics
to the same subnet must be before the metrics are considered equal. The variance router
subcommand is used to set the value.
24
When using RIP, what configuration command controls the number of equal-cost routes
that can be added to the routing table at the same time? What is the maximum number of
equal-cost routes to the same destination that can be included in the IP routing table at
once?
The ip maximum-paths x router subcommand is used in RIP configuration mode to set
the number. The maximum is 6, and the default is 4.
25
When using IGRP, what configuration command controls the number of equal-cost routes
that can be added to the routing table at the same time? What is the maximum number of
equal-cost routes to the same destination that can be included in the IP routing table at
once?
The ip maximum-paths x router subcommand is used in IGRP configuration mode to set
the number. The maximum is 6, and the default is 4.
26
What feature supported by RIP-2 allows it to support variable-length subnet masks
(VLSM)?
The association and transmission of mask information with each route allows VLSM
support with any routing protocol, RIP-2 included.
27
Name three features of RIP-2 that are not features of RIP-1.
The features included in RIP-2 but not in RIP-1 include: transmission of subnet mask with
routes, authentication, next-hop router IP address in routing update, external route tags,
and multicast routing updates.
28
What configuration commands are different between a router configured for RIP-1 and a
router configured for only support of RIP-2?
The router rip and network commands would be identical. The RIP-2 router would
require a version 2 router subcommand to enable RIP-2.
29
Identify reasons for using tunneling.
The four reasons outlined in this text are: to allow multiprotocol traffic to flow over an IP
backbone, to support VPNs, to overcome discontiguous network problems, and to
overcome the shortcoming of some routing protocols with low maximum metric
limitations. Other reasons also might be valid because this question is somewhat
subjective.
apA.fm Page 752 Monday, March 20, 2000 5:24 PM