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Appendix
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Answers to Practice Test Questions
20. D. The administrative distance of the Routing Information Protocol (RIP) is 120. The
administrative distance of 90 is used for internal Enhanced Interior Gateway Routing
Protocol (EIGRP). The administrative distance of 100 is used for Interior Gateway
Routing Protocol (IGR). The administrative distance of 110 is used for Open Shortest.
21. B. Administrative distance (AD) is an order of reliability between dynamic routing
protocols and static routes. Administrative distances do not define protocol standards;
they only reference them. Administrative distances do not allow for the shortest distance
between routers; they allow the router to choose the best path to the destination
network. Although administrative distances are programmed into route statements by
administrators, they do not calculate path selection.
22. A. A directly connected network has an administrative distance (AD) of 0 and is the
most highly reliable. The administrative distance of 1 is used for static entries. The
administrative distance of 5 is used for Enhanced Interior Gateway Routing Protocol
summary routes. Directly connected networks have an AD of 0 that is trusted over all
other router sources.
23. A. Internal EIGRP has an administrative distance (AD) of 90. The AD of 100 is used for
Interior Gateway Routing Protocol (IGRP). The administrative distance of 110 is used for
Open Shortest Path First (OSPF). The administrative distance of the Routing Information
Protocol (RIP) is 120.
24. C. The administrative distance (AD) is a rating of trust between different routing
protocols and route methods. This trust scale is important when multiple routes exist
to the same destination. Directly connected routes have ADs with the highest level
of trust. Route statements populated by the same dynamic routing protocol will be
calculated for the best route upon their metric and not their administrative distance.
The administrative distance is not assigned by the administrator for route selection. The
administrative distance value is not associated with the cost to the destination, only the
trust of a route statement.
25. A. Enhanced Interior Gateway Routing Protocol (EIGRP) uses bandwidth and delay by
default for calculating routes. The bandwidth should be set to the actual bandwidth of the
link so that routing protocols such as EIGRP can calculate the best route. Delay cannot
be set because it is a variable of the interface based upon the delay of a packet traversing
the interface. Reliability cannot be set because it is a variable of the interface based upon
the reliability of the link. Load cannot be set because it is also a variable of the interface,
based upon the load of the interface.
26. C. The administrative distance (AD) of EIGRP is 90. The most common ADs are 90 for
EIGRP, 100 for IGRP, 110 for OSPF, and 120 for RIP. The mnemonic of 90 Exotic Indian
Oval Rubies will help you remember the order; then starting with EIGRP with a value of
90, increment the following values by 10.
Chapter 3: IP Connectivity (Domain 3)
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