13. Which table is used by EIGRP to store all routes that are learned from EIGRP neighbors?
- the routing table
- the neighbor table
- the topology table
- the adjacency table
Explanation: EIGRP routers maintain a topology table that includes entries for every destination that the router learns from directly connected EIGRP neighbors.
14. Which multicast address does an EIGRP-enabled router use to send query packets?
- 224.0.0.10
- 224.0.0.9
- 224.0.0.12
- 224.0.0.5
Explanation: 224.0.0.10 is the reserved IPv4 multicast address that is used by EIGRP.
15. Which three metric weights are set to zero by default when costs in EIGRP are being calculated? (Choose three.)
- k1
- k2
- k3
- k4
- k5
- k6
Explanation: By default, k1 and k3 are set to one and k2, k4, and k5 are set to zero during cost calculation by the EIGRP process. There is no k6 value.
16. Where should EIGRP summarization be applied?
- on the router interface that connects to the internet
- on the area border router
- on any interface where end-user devices attach
- on any router interface participating in the EIGRP process
Explanation: In summarizing routes within EIGRP, the command is applied to an interface. Summarization reduces the routing table and the time for convergence.
17. When are EIGRP update packets sent?
- only when necessary
- when learned routes age out
- every 5 seconds via multicast
- every 30 seconds via broadcast
Explanation: EIGRP does not send update packets periodically. It only sends them when necessary. Route entries in EIGRP routing table do not age out.
18. How is bandwidth to a destination network calculated by EIGRP?
- the lowest configured bandwidth of any interface along the route
- the sum of the configured bandwidths of all interfaces along the path
- the highest configured bandwidth of any interface along the path
- the bandwidth of the ingress interface of the last hop router
Explanation: By default, EIGRP uses bandwidth and delay to calculate a metric to a destination network. The bandwidth calculation is made by using the lowest configured bandwidth of any interface along the route.
19. Refer to the exhibit. What does the value 2816 represent in the output display?
- feasible distance
- shortest distance
- reported distance
- administrative distance
Explanation: The value 2816 in (2170112/2816) is the “reported distance,” the metric of the neighbor router (192.168.1.6) to reach the destination network. The value 2170112 is the feasible metric cost to reach the destination network.
20. Which algorithm does the EIGRP routing protocol use?
- Bellman-Ford
- RSA
- Dijkstra
- DUAL
Explanation: Routing protocol algorithms include Bellman-Ford used with RIP, Dijkstra used with OSPF, and DUAL used with EIGRP. Rivest-Shamir-Adleman (RSA) is an algorithm used with encryption.
21. Which two factors does an EIGRP router use to determine that a route to a remote network meets the feasible condition and is therefore loop-free? (Choose two.)
- the successor route on a neighbor router
- the feasible successor route on the remote router
- the reported distance on a neighbor router
- the administrative distance on the remote router
- the feasible distance on the local router
Explanation: The EIGRP feasible condition (FC) is met when the reported distance (RD) on a neighbor router to a network is less than the local router feasible distance (FD) to the same destination network.
22. When will a router that is running EIGRP put a destination network in the active state?
- when the EIGRP domain is converged
- when there is outgoing traffic toward the destination network
- when there is an EIGRP message from the successor of the destination network
- when the connection to the successor of the destination network fails and there is no feasible successor available
Explanation: If the connection to the successor of a network is lost and there is no feasible successor in the topology database, DUAL will put the network into the active state and actively query the neighbors for a new successor. In a normal circumstance when the network is reachable and traffic is normal, the network will be put in the passive mode.
23. Refer to the exhibit. R2 has two possible paths to the 192.168.10.4 network. What would make the alternate route meet the feasibility condition?
- a reported distance less than 3523840
- a reported distance greater than 41024000
- a feasible distance greater than 41024000
- an administrative distance less than 170
Explanation: To meet the feasibility condition, the reported distance (RD) to a network must be less than the current feasible distance to the same destination network. In this example the current feasible distance is 3523840. This means that to be a feasible successor, a route would need a reported distance less than 3523840.
24. What is a characteristic of manual route summarization?
- requires high bandwidth utilization for the routing updates
- reduces total number of routes in routing tables
- cannot include supernet routes
- has to be configured globally on the router
Explanation: Manual route summarization reduces the total number of routes in routing tables. It also requires less bandwidth utilization for the routing updates because a single route can be sent instead of multiple individual routes. It can include supernet routes and is configured on a specified EIGRP interface.
“Do I Know This Already?” Quiz Answers:
1. EIGRP uses the protocol number _______ to identify its packets.
- 87
- 88
- 89
- 90
Explanation: EIGRP uses protocol number 88.
2. EIGRP uses _______ packet types for inter-router communication.
- three
- four
- five
- six
- seven
Explanation: EIGRP uses the hello, request, reply, update, and query packet types.
3. What is an EIGRP successor?
- The next-hop router for the path with the lowest path metric for a destination prefix
- The path with the lowest metric for a destination prefix
- The router selected to maintain the EIGRP adjacencies for a broadcast network
- A route that satisfies the feasibility condition where the reported distance is less than the feasible distance
Explanation: An EIGRP successor is the next-hop router for the successor route (which is the loop-free route with the lowest path metric).
4. Which of the following attributes does the EIGRP topology table contain? (Choose all that apply.)
- destination network prefix
- hop count
- total path delay
- maximum path bandwidth
- list of EIGRP neighbors
Explanation: The EIGRP topology table contains the destination network prefix, path attributes (hop count, minimum path bandwidth, and total path delay), and a list of nearby EIGRP neighbors.
5. Which of the following destination addresses does EIGRP use when feasible? (Choose two.)
- IP address 224.0.0.9
- IP address 224.0.0.10
- IP address 224.0.0.8
- MAC address 01:00:5E:00:00:0A
- MAC address 0C:15:C0:00:00:01
Explanation: EIGRP uses the multicast IP address 224.0.0.10 or MAC address 01:005E:00:00:0A when feasible.
6. Which value can be modified on a router to manipulate the path taken by EIGRP but avoid having impacts on other routing protocols, such as OSPF?
- interface bandwidth
- interface MTU
- interface delay
- interface priority
Explanation: The interface delay can be modified to change the EIGRP path calculations without modifying the path calculation of OSPF.
7. EIGRP uses a reference bandwidth of ________ with the default metrics.
- 100 Mbps
- 1 Gbps
- 10 Gbps
- 40 Gbps
Explanation: EIGRP uses a reference bandwidth of 10 Gbps with the default metrics.
8. The default EIGRP hello timer for a high-speed interfaces is ______.
- 1 second
- 5 seconds
- 10 seconds
- 20 seconds
- 30 seconds
- 60 seconds
Explanation: EIGRP uses a default hello timer of 5 seconds for high-speed interfaces.
9. When a path has been identified using EIGRP and in a stable fashion, the route is considered ______.
- passive
- dead
- active
- alive
Explanation: EIGRP considers stable paths to be passive.
10. How does an EIGRP router indicate that a path computation is required for a specific route?
- EIGRP sends out an EIGRP update packet with the topology change notification flag set.
- EIGRP sends out an EIGRP update packet with a metric value of zero.
- EIGRP sends out an EIGRP query with the delay set to infinity.
- EIGRP sends a route withdrawal, notifying other neighbors to remove the route from the topology table.
Explanation: EIGRP sends out a query packet with the delay set to infinity to indicate that a route has gone active.
11. True or false: EIGRP summarization occurs for network prefixes as it crosses all network interfaces.
- True
- False
Explanation: Summarization of prefixes occurs as traffic is advertised out an interface with summarization configured.