662 Appendix A: Answers to Review Questions
8
List six rules for designing a scalable OSPF internetwork.
No more than six hops from source to destination.
50 routers per area.
All areas connect to Area 0.
Do not allow more than two areas per ABR.
Use totally stubby areas.
Maximize summarization.
9
How does OSPF route summarization save router resources?
Summarization reduces the memory and the CPU processing load on the routers.
10
What is the meaning of cost, and how does OSPF calculate cost?
Cost is the metric that OSPF uses to determine the shortest path. The metric is added from
source to destination over all outgoing links. OSPF defines cost as 10 E8/BW.
11
What is the difference between an External Type 1 route and an External Type 2 route?
External Type 1 routes use a metric that is the sum of the external metric and the collective
internal cost of reaching the destination.
External Type 2 routes use a metric that examines the external metric and does not take
the internal cost into consideration.
12
Which routing protocols are supported by EIGRP?
IP, IPX, AppleTalk.
13
EIGRP updates are
A. periodic
B. incremental
C. A and B
D. None of the above
Answer is B, incremental
14
Name five values that IGRP and EIGRP use to determine metrics. Which metrics are used
by default?
By default, IGRP metric = bandwidth + delay.
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