Review Questions

1.	What is the purpose of LSAs? They elect DRs and BDRs. They broadcast a link-state change. They distribute a list of active links to neighbor routers. They distribute a list of network services provided by links.
2.	Which protocols do not use a topology table? (Choose all that apply.) EIGRP IGRP RIP1 OSPF
3.	Which route type must be redistributed by a routing protocol if other routers are to learn about it? RIP Default routes Connected routes Static routes
4.	Why are passive interfaces used within routing protocols such as RIP and IGRP? To stop unwanted route information from entering the specified interface To allow route information to be filtered by an access list To allow routes to be sent out the specified interface, but deny route information to enter the interface To allow routes to enter the interface, but deny any route information to exit the specified interface
5.	How is a feasible successor chosen when a route fails? The route with the next lowest metric is chosen. If a router doesn’t have a feasible successor, queries are multicast to neighboring routers in search of a feasible successor. The route is removed from the route table. The route is flagged as an active state.
6.	What configuration option changes a stub area to a totally stub area? area area-id stub no-summary area area-id total stub area process-id stub area process-id stub no-summary
7.	Which OSPF initialization states allow routers to actually exchange route information? (Choose all that apply.) The loading state The two-way state The full state The exchange state
8.	What two characteristics distinguish a stub area from a totally stub area? (Choose all that apply.) A totally stub area accepts summary routes. A totally stub area is Cisco proprietary. A totally stub area contains only intra-area routes. A totally stub area contains only inter-area routes.
9.	What three enhancements were made to OSPF to make it better than RIP version 1? (Choose all that apply.) No hop-count limit Use of distance-vector algorithm Use of classfull routing Incremental routing updates Route tables are calculated after the change has been propagated.
10.	Which commands are used to verify correct operation of OSPF? (Choose all that apply.) show ip ospf area-id show ospf database show ip ospf border-routers show ip ospf process-id show ip ospf links show ip ospf database [network | summary | asbr- summary | external | database-summary] show ip ospf virtual-links
11.	What are the commands needed to implement OSPF on a router? (Choose two.) router ip ospf area-id router ospf area-id router ospf process-id network address mask area-id network address wildcard-mask area-id network address wildcard-mask area area-id
12.	What is the difference between an ABR and an ASBR? An ABR is the border router between two or more defined areas, and an ASBR is a border router between an OSPF area and external autonomous system. An ASBR is the border router between two or more defined areas, and an ABR is a border router between an OSPF area and external autonomous system. An ABR is the area backbone router that connects the backbone routers, and an ASBR borders different autonomous systems. An ASBR is the autonomous system backbone router that connects the backbone to other autonomous systems, and the ABR is the area border router.
13.	What is true about link-state networks? Choose the best answer. They maintain a more complex table than distance-vector-based networks. They maintain a less complex table than distance-vector-based networks. They don’t use convergence. They use RIP timers.
14.	What is the metric for OSPF? Bandwidth Delay Hop count Cost
15.	Have-a-Seat has specified that the IP routing protocol must adhere to recent industry standards and must scale to support a large network. Which routing protocol should you recommend to Have-a-Seat? RIP EGP IGRP OSPF
16.	Scott from the Willow Creek School District has informed you that he has Bay and 3Com routers that he wants you to include in your network design. Since he wants to keep them, what routing protocol should you use? RIP IGRP OSPF EIGRP
17.	What is IS-IS routing within a single area referred to as? Level 2 routing Level 3 routing Level 1 routing inter-area routing
18.	Which of the following IS-IS configuration is required? Enabling IS-IS and assigning areas Enabling IP routing for an area on an interface Configuring IS-IS interface parameters Configuring miscellaneous IS-IS parameters
19.	IS-IS routers establish Level 2 adjacencies to perform routing between ___________ areas. Level 3 Level 2 inter-area Level 1
20.	What does EIGRP use to find the best path to a remote network by default? Hop count Bandwidth Load Delay MTU

Answers

1.	C There are five primary types of LSAs that are used between OSPF routers to distribute the list of active network links.
2.	B, C IGRP and RIP1 do not use a topology table to calculate route updates because they are distance-vector protocols.
3.	D Static routes must be redistributed, but all other types are sent automatically in route updates.
4.	D To prevent route updates from being sent to an unknown or unneeded router, the passive interface command can be used.
5.	A OSPF chooses a feasible successor when a primary route becomes unavailable; the metric value is used to determine the best route.
6.	A The IOS command to configure an OSPF area as totally stubby is area area-id stub no-summary.
7.	A, C During the OSPF loading state, routers send link-state request packets. Full state indicates that all routers have the same link-state database and can begin the state of exchange.
8.	B, C Cisco routers support OSPF totally stub areas, which contain only intra-area routes because there are no other networks within.
9.	A, D, E OSPF supports an unlimited number of network hops, incremental routing updates, and topology tables that include link- state updates.
10.	C, D, F, G The IOS command show ip ospf border-routers verifies ABR and ASBR operation. The show ip ospf process-id can be used to verify correct configuration. The other two commands are also used to verify the correct operation of the OSPF database updates and calculations.
11.	C, F The required OSPF IOS configuration commands are router ospf process-id and network address wildcard-mask area areaid.
12.	A The ABR includes the link-state updates for its connected areas, and the ASBR is configured with autonomous system areas to advertise externally.
13.	A Link-state routing protocols include adjacency, link-state, and forwarding tables and use more complex calculations to determine the best route.
14.	D OSPF uses cost as a routing metric in which bandwidth is one of the most important metrics for route selection. The Dijkstra algorithm is used to choose the lowest cost link for route selection, and the cost of the local router is added to the cost required to reach the destination.
15.	D OSPF is an industry-standard routing protocol and is very scalable.
16.	C OSPF is supported by most vendors’ routers and is very scalable.
17.	C IS-IS routing in a single area is called Level 1 routing.
18.	A Enabling IS-IS and assigning areas is required for IS-IS routing configuration. The other tasks are optional with IS-IS.
19.	D IS-IS level 2 routers establish adjacencies to route between Level 1 areas.
20.	B, D Enhanced IGRP uses bandwidth and delay of the line by default to find the best path to a remote network. MTU, reliability, and load can be configured by the administrator, but they are not used by default.