Networking - EIGRP and OSPF

Exercise :: EIGRP and OSPF - EIGRP and OSPF

  • EIGRP and OSPF - EIGRP and OSPF
11. 

What are reasons for creating OSPF in a hierarchical design?

  1. To decrease routing overhead
  2. To speed up convergence
  3. To confine network instability to single areas of the network
  4. To make configuring OSPF easier

A. 1, 2 and 3
B. 3 only
C. 3 and 4
D. 2, 3 nd 4

Answer: Option A

Explanation:

OSPF is created in a hierarchical design, not a flat design like RIP. This decreases routing overhead, speeds up convergence, and confines network instability to a single area of the network.

12. 

Which two of the following commands will place network 10.2.3.0/24 into area 0?

  1. router eigrp 10
  2. router ospf 10
  3. network 10.0.0.0
  4. network 10.2.3.0 0.0.0.255 area0
  5. network 10.2.3.0 0.0.0.255 area 0

A. 1 and 4
B. 2, 4, and 5
C. 2 and 5
D. 3 and 4

Answer: Option C

Explanation:

To enable OSPF, you must first start OSPF using a Process ID. The number is irrelevant; just choose a number from 1 to 65,535 and you're good to go. After you start the OSPF process, you must configure any network that you want advertised via OSPF using wildcards and the area command. Statement (4) is wrong because there must be a space after the parameter area and before you list the area number.

13. 

If routers in a single area are configured with the same priority value, what value does a router use for the OSPF Router ID in the absence of a loopback interface?

A. The lowest IP address of any physical interface
B. The highest IP address of any physical interface
C. The lowest IP address of any logical interface
D. The highest IP address of any logical interface

Answer: Option B

Explanation:

At the moment of OSPF process startup, the highest IP address on any active interface will be the Router ID (RID) of the router. If you have a loopback interface configured (logical interface), then that will override the interface IP address and become the RID of the router automatically.

14. 

Which of the following protocols support VLSM, summarization, and discontiguous networking?

  1. RIPv1
  2. IGRP
  3. EIGRP
  4. OSPF
  5. BGP
  6. RIPv2

A. 1 and 4
B. 2 and 5
C. 3, 4 and 6
D. All of the above

Answer: Option C

Explanation:

RIPv1 and IGRP are true distance-vector routing protocols and can't do much, really-except build and maintain routing tables and use a lot of bandwidth! RIPv2, EIGRP, and OSPF build and maintain routing tables, but they also provide classless routing, which allows for VLSM, summarization, and discontiguous networking.

15. 

You get a call from a network administrator who tells you that he typed the following into his router:

Router(config)#router ospf 1
Router(config-router)#network 10.0.0.0 255.0.0.0 area 0
He tells you he still can't see any routes in the routing table. What configuration error did the administrator make?

A. The wildcard mask is incorrect.
B. The OSPF area is wrong.
C. The OSPF Process ID is incorrect.
D. The AS configuration is wrong.

Answer: Option A

Explanation:

The administrator typed in the wrong wildcard mask configuration. The wildcard should have been 0.0.0.255.