Written Questions
1. What four routed protocols are supported by EIGRP?
2. When is redistribution required for EIGRP?
3. What command would be used to enable EIGRP with an autonomous system number of 300?
4. What command will tell EIGRP that it is connected to network 172.10.0.0?
5. What type of EIGRP interface will neither send nor receive Hello packets?
6. Write the command that will enable OSPF process 101 on a router.
7. Write the command that will display details of all OSPF routing processes enabled on a router.
8. Write the command that will display interface-specific OSPF information.
9. Write the command that will display all OSPF neighbors.
10. Write the command that will display all different OSPF route types that are currently known by the router.
Review Questions
1. There are three possible routes for a router to reach a destination network. The first route is from OSPF with a metric of 782. The second route is from RIPv2 with a metric of 4. The third is from EIGRP with a composite metric of 20514560. Which route will be installed by the router in its routing table?
A. RIPv2
B. EIGRP
C. OSPF
D. All three
2. Which EIGRP information is held in RAM and maintained through the use of Hello and update packets? (Choose two.)
A. Neighbor table
B. STP table
C. Topology table
D. DUAL table
3. Which of the following describe the process identifier that is used to run OSPF on a router? (Choose two.)
B. It is globally significant.
E. All routes in the same OSPF area must have the same Process ID if they are to exchange routing information.
A. In the routing table only
B. In the neighbor table only
C. In the topology table only
B. show ip eigrp summary
C. show ip eigrp topology
D. show ip eigrp adjacencies
E. show ip eigrp neighbors detail
6. 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.
7. Which of the following protocols support VLSM, summarization, and discontiguous networking? (Choose three.)
A. RIPv1
B. IGRP
C. EIGRP
D. OSPF
E. RIPv2
D. If your design is hierarchical, then you don’t need multiple areas.
E. All areas must connect to area 0.
9. Which of the following network types have a designated router and a backup designated router assigned? (Choose two.)
A. Broadcast
B. Point-to-point
C. NBMA
D. NBMA point-to-point
E. NBMA point-to-multipoint
10. A network administrator needs to configure a router with a distance-vector protocol that allows classless routing. Which of the following satisfies those requirements?
A. IGRP
B. OSPF
C. RIPv1
D. EIGRP
E. IS-IS
11. You need the IP address of the devices with which the router has established an adjacency. Also, the retransmit interval and the queue counts for the adjacent routers need to be checked. What command will display the required information?
A. show ip eigrp adjacency
B. show ip eigrp topology
C. show ip eigrp interfaces
D. show ip eigrp neighbors
12. For some reason, you cannot establish an adjacency relationship on a common Ethernet link between two routers. Looking at the output below, what is the cause of the problem?
RouterA#
Internet Address 172.16.1.2/16, Area 0
Process ID 2, Router ID 172.126.1.2, Network Type BROADCAST, Cost: 10
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 172.16.1.2, interface address 172.16.1.1
Timer intervals configured, Hello 5, Dead 20, Wait 20, Retransmit 5
RouterB#
Internet Address 172.16.1.1/16, Area 0
Process ID 2, Router ID 172.126.1.1, Network Type BROADCAST, Cost: 10
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 172.16.1.1, interface address 172.16.1.2
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
A. The OSPF area is not configured properly.
B. The priority on RouterA should be set higher.
C. The cost on RouterA should be set higher.
D. The Hello and Dead timers are not configured properly.
13. Which is true regarding EIGRP successor routes? (Choose two.)
A. Broadcast multi-access
B. Non-broadcast multi-access
C. Point-to-point
D. Broadcast multipoint
A. router eigrp 10
B. router ospf 10
C. router rip
D. network 10.0.0.0
E. network 10.2.3.0 255.255.255.0 area 0
F. network 10.2.3.0 0.0.0.255 area0
G. network 10.2.3.0 0.0.0.255 area 0
16. With which network type will OSPF establish router adjacencies but not perform the DR/BDR election process?
A. Point-to-point
C. Broadcast multi-access
D. Non-broadcast multi-access
A. To decrease routing overhead
B. To speed up convergence
D. To make configuring OSPF easier
18. What is the administrative distance of OSPF?
A. 90
B. 100
C. 110
D. 120
19. You have an internetwork as shown in the following illustration. However, the two networks are not sharing routing table route entries. Which command is needed to fix the problem?
A. version 2
C. redistribute eigrp 10
D. default-information originate
20. 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?
C. The lowest IP address of any logical interface
D. The highest IP address of any logical interface
Written Answers:
2. Redistribution is required when more than one EIGRP session or process is running and they are identified with different ASNs. Redistribution shares topology information between EIGRP sessions.
3. router eigrp 300
4. network 172.10.0.0
5. Passive interface
6. router ospf 101
7. show ip ospf
9. show ip ospf neighbor
10. show ip route ospf
Review Answers:
1. B. Only the EIGRP routes will be placed in the routing table because it has the lowest administrative distance (AD), and that is always used before metrics.
2. A, C. EIGRP maintains three tables in RAM: neighbor, topology, and routing. The neighbor and topology tables are built and maintained with the use of Hello and update packets.
3. A, C. The Process ID for OSPF on a router is only locally significant and you can use the same number on each router, or each router can have a different number—it just doesn’t matter. The numbers you can use are from 1 to 65,535. Don’t get this confused with area numbers, which can be from 0 to 4.2 billion.
4. E. Successor routes are going to be in the routing table since they are the best path to a remote network. However, the topology table has a link to each and every network, so the best answer is topology table and routing table. Any secondary route to a remote network is considered a feasible successor, and those routes are found only in the topology table and used as backup routes in case of primary route failure.
5. C. Any secondary route to a remote network is considered a feasible successor, and those routes are found only in the topology table and used as backup routes in case of primary route failure. You can see the topology table with the show ip eigrp topology command.
6. A. The administrator typed in the wrong wildcard mask configuration. The wildcard should have been 0.0.0.255 or even 0.255.255.255.
7. C, D, E. 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.
8. C, D, E. Loopback interfaces are created on a router, and the highest IP address on a loopback (logical) interface becomes the RID of the router but has nothing to do with areas and is optional, so option A is wrong. The numbers you can create an area with are from 0 to 4,294,967,295—option B is wrong. The backbone area is called area 0, so option C is correct. All areas must connect to area 0, so option E is correct. If you have only one area, it must be called area 0, so option F is incorrect. This leaves option D, which must be correct; it doesn’t make much sense, but it is the best answer.
9. A, C. No DR is assigned on any type of point-to-point link. No DR/BDR is assigned on the NBMA point-to-multipoint due to the hub/spoke topology. DR and BDR are elected on broadcast and non-broadcast multi-access networks. Frame Relay is a non-broadcast multi-access (NBMA) network by default.
10. D. In this question, we’re calling EIGRP just plain old distance vector. EIGRP is an advanced distance-vector routing protocol, sometimes called a hybrid routing protocol because it uses the characteristics of both distance-vector and link-state routing protocols.
11. D. The show ip eigrp neighbors command allows you to check the IP addresses as well as the retransmit interval and queue counts for the neighbors that have established an adjacency.
12. D. The Hello and Dead timers must be set the same on two routers on the same link or they will not form an adjacency (relationship). The default timers for OSPF are 10 seconds for the Hello timer and 40 seconds for the Dead timer.
13. A, D. Successor routes are the routes picked from the topology table as the best route to a remote network, so these are the routes that IP uses in the routing table to forward traffic to a remote destination. The topology table contains any route that is not as good as the successor route and is considered a feasible successor, or backup route. Remember that all routes are in the topology table, even successor routes.
14. A, B. DR and BDR are elected on broadcast and non-broadcast multi-access networks. Frame Relay is a non-broadcast multi-access (NBMA) network by default. No DR is assigned on any type of point-to-point link. No DR/BDR is assigned on the NBMA point-to-multipoint due to the hub/spoke topology.
15. B, G. 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 interfaces on which to activate OSPF using the network command with wildcards and specification of an area. Option F is wrong because there must be a space after the parameter area and before you list the area number.
16. A. No DR is assigned on any type of point-to-point link. No DR/BDR is assigned on the NBMA point-to-multipoint due to the hub/spoke topology. DR and BDR are elected on broadcast and non-broadcast multi-access networks. Frame Relay is a non-broadcast multi-access (NBMA) network by default.
17. A, B, C. 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.
18. C. The administrative distance (AD) is a very important parameter in a routing protocol. The lower the AD, the more trusted the route. If you have IGRP and OSPF running, by default IGRP routes would be placed in the routing table because IGRP has a lower AD of 100. OSPF has an AD of 110. RIPv1 and RIPv2 both have an AD of 120, and EIGRP is the lowest, at 90.
19. B. The network in the diagram is considered a discontiguous network because you have one classful address subnetted and separated by another classful address. Only RIPv2, OSPF, and EIGRP can work with discontiguous networks, but RIPv2 and EIGRP won’t work by default. You must use the no auto-summary command under the routing protocol configuration.
20. B. 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.
Questions come from , I added my own explanations.
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