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Answers to Assessment Test

xlvii

B, D, F. The Cisco three-layer model includes the Core, Distribution,
and Access layers. See Chapter 1 for more information on the Cisco
three-layer model.

A, C. Link-state protocols do not send entire routing table updates
like distance-vector protocols do. Link-state uses Hello messages to
make sure that neighbor routers are still alive, and then when a change
in the network does occur, it sends only the necessary information
about the change. See Chapter 2 for more information on the link-
state routing protocols.

10.

D. The

command

router eigrp

is used followed by the AS number

to implement EIGRP. You must then identify the attached networks
using the network command. See Chapter 6 for more information.

11.

C. The IOS command to set a router's priority is ip ospf priority
priority_number

, where priority_number is a number from 0 to

255. See Chapter 4 for more information.

12.

D. Network 127 is reserved for loopback purposes (e.g., for trouble-
shooting diagnostics). With a local loopback address, a host can send
a test packet to itself without generating network traffic. For more
information, see Chapter 3.

13.

B. The Diffusing Update Algorithm (DUAL) is used to calculate
routes in EIGRP. See Chapter 6 for more information.

14.

C. Values for the load metric range from 1 through 255. Therefore,
a load metric of 100 indicates an approximate load of 39 percent
(100/255 = 39.2). For more information, see Chapter 10.

15.

C. Port 179 is used by BGP to establish a session with another BGP
peer. Ports 20 and 21 are used by FTP, and port 23 is used by Telnet.
For more information, see Chapter 7.

16.

B. The Core layer should provide a fast transport between Distribu-
tion layer devices. See Chapter 1 for more information on the Cisco
three-layer model.

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