EIGRP Flashcards
Prevents routers from advertising a route through the same interface from which the route was learned. Prevents routing loops
split horizon
Prevents routing loops by advertising the route as unreachable to the interface from which the route was received.
Poison reverse
Prevents routing loops by suppressing information regarding a better path to a route for a specified period of time. When a router receives a routing update stating that a route is unreachable, the router waits a specified amount of time before accepting routes advertised by other sources.
Hold-down timers
What must match to enable the exchange of routing updates between EIGRP neighbors?
ASN (Autonomous System Number)
Route _____ should only be used when a router is configured with multiple routing protocols and the network design calls for routing table updates to be shared across protocols.
redistribution
Each route in the router topology table contains two numbers inside parenthesis separated by a /. What does the first and second numbers represent?
First - metric
Second - reported distance (advertised distance)
What is the lowest calculated metric to the destination network?
feasible distance
The distance that the next-hop router has calculated for the route
reported distance
If the ____ is less than the _____, the route can be a feasible successor.
RD FD
If the ____ is greater than the _____, the route cannot be a feasible successor and is not listed in the topology table.
RD FD
Does the RD have anything to do with whether or not the route is listed in the routing table?
No, only metric does
EIGRP by default is configured for _____ load-balancing
equal-cost
Equal-cost load balancing occurs when the variance is set to the default value of ____.
1
Multiplier used to determine whether feasible successors can be used for unequal-cost path load balancing
variance
If the variance is set to 2, feasible successor routes that have metrics less than ____ times the lowest metric can be used for load balancing.
2
What command allows you to verify that EIGRP is sending hello packets?
show ip eigrp traffic
What does EIGRP use to achieve rapid convergence?
DUAL
What is the calculation for feasible distance?
advertised distance + reported metric to neighbor
A router compares all ____ to reach a specific network and selects the lowest one and places it in the routing table.
FD
How can the next-hop router become the feasible successor?
Must have AD that is less than the FD of the current successor route
What two criteria does EIGRP use to calculate its metric?
Bandwidth
Delay
In addition to bandwidth and delay, what criteria can EIGRP use to calculate its metric?
reliability
load
By default, what K values are set to 1?
K1 and K3
What is the multicast address for EIGRP to send routing information to all EIGRP routers?
224.0.0.10
What are the values of K1 through K5
K1 - bandwidth
K2 - load
K3 - delay
K4 - Reliability
K5 - MTU
Unlike OSPF, EIGRP does not go through neighbor states. When is a neighbor relationship established?
Upon receipt of hello packet
What must match in order for a router to form an adjacency?
AS number
K values
Authentication parameters
When will EIGRP send the contents of its routing table to the neighbor?
As soon as adjacency is established
What happens when a route changes?
EIGRP will send incremental updates to 224.0.0.10
What do incremental updates contain?
Information about the changed routes
What Cisco proprietary protocol is used to send EIGRP route updates?
RTP (Reliable Transport Protocol)
What happens when you issue a passive interface command on an EIGRP interface?
It suppresses incoming and outgoing hello packets
What can be used to suppress only outbound routing updates?
distribute list
What command will show if metric weights have been issued on a router?
show run
What commands configures R4 with the default EIGRP metric weight values?
no metric weights metric weights 0 1 0 1 0 0
What do the numbers after the metric weights command represent?
k values
What number multiplier values can be configured for the variance command?
1 - 128
What does disabling auto summarization (no auto-summary) do?
Configures EIGRP to advertise the actual subnet instead of the classful summary
What distance vector feature prevents routing loops by causing the routing protocol to advertise only a subset of known routes, as opposed to the full routing table, under normal stable conditions?
Split horizon
What distance vector feature prevents routing loops by advertising an infinite metric when a route fails?
Route poisoning
Routers A and B use EIGRP. How does router A watch for the status of router B so that router A can react if router B fails?
By using EIGRP hello messages, with A needing to receive periodic Hello messages to believe B is still working
What affects the calculation of EIGRP metrics when all possible default values are used?
Bandwidth
Delay
The calculated metric of the successor route
feasible distance
The metric of a route from a neighboring router’s perspective.
reported (advertised) distance
What is the default hello timer on an Ethernet LAN?
5 seconds
What is the default hold time for an Ethernet LAN?
15 seconds
Do timers have to match between neighbors?
No
What is the purpose of the hold timer?
It tells the neighboring router to wait the specified amount of time and if no hello is received within that amount of time, they can bring down the adjacency
What command changes the hello timer in interface configuration mode for AS number 1 to 2 seconds?
ip hello-interval eigrp 1 2
What command changes the hold timer in interface configuration mode for AS number 1 to 6 seconds?
ip hold-time eigrp 1 6
What command allows you to view the hello interval and hold timers?
show ip eigrp interface detail
What four steps must be performed to enable EIGRPv6 on a router?
Globally enable IPv6 routing on the Cisco device
Enable the EIGRPv6 routing process
Configure the link that is participating in EIGRPv6
No shutdown command is configured for routing process
What are two drawbacks of implementing a link-state routing protocol? (Choose two)
- The sequencing and acknowledgement of link-state packets
- The requirement for a hierarchical IP addressing scheme for optimal functionality
- The high volume of link-state advertisements in a converged network
- The high demand on router resources to run the link-state routing algorithm
- The large size of the topology table listing all advertised routes in the converged network
- The requirement for a hierarchical IP addressing scheme for optimal functionality
- The high demand on router resources to run the link-state routing algorithm
What are the two drawbacks of implementing a link-state routing protocol?
The requirement for a hierarchical IP addressing scheme for optimal functionality.
The high demand on router resources to run the link-state routing algorithm
Which type of EIGRP route entry describes a feasible successor route?
a backup route, stored in the topology table
What information does a router running a link-state protocol use to build and maintain its topological database? (Choose two)
hello packets
SAP messages sent by other routers
LSAs from other routers
beacons received on point-to-point links routing tables received from other link-state routers
TTL packets from designated routers
hello packets
LSAs from other routers
Which EIGRP for IPv6 command can you enter to view the link-local addresses of the neighbors of a device?
show ipv6 eigrp neighbors
Which option describes a difference between EIGRP for IPv4 and IPv6?
- Only EIGRP for IPv6 advertises all connected networks
- Only EIGRP for IPv6 requires a router ID to be configured under the routing process
- AS numbers are configured in EIGRP but not in EIGRPv3
- Only EIGRP for IPv6 is enabled in the global configuration mode
Only EIGRP for IPv6 requires a router ID to be configured under the routing process
Refer to the exhibit. When running EIGRP, what is required for RouterA to exchange routing updates with RouterC?
A. AS numbers must be changed to match on all the routers
B. Loopback interfaces must be configured so a DR is elected
C. The no auto-summary command is needed on Router A and Router C
D. Router B needs to have two network statements, one for each connected network
A. AS numbers must be changed to match on all the routers
Refer to the exhibit. Based on the exhibited routing table, how will packets from a host within the 192.168.10.192/26 LAN be forwarded to 192.168.10.1?
A. The router will forward packets from R3 to R2 to R1.
B. The router will forward packets from R3 to R1 to R2.
C. The router will forward packets from R3 to R2 to R1 AND from R3 to R1.
D. The router will forward packets from R3 to R1.
C. The router will forward packets from R3 to R2 to R1 AND from R3 to R1.
What does a router do if it has no EIGRP feasible successor route to a destination network and the successor route to that destination network is in active status?
A. It routes all traffic that is addressed to the destination network to the interface indicated in the routing table.
B. It sends a copy of its neighbor table to all adjacent routers.
C. It sends a multicast query packet to all adjacent neighbors requesting available routing paths to the destination network.
D. It broadcasts Hello packets to all routers in the network to re-establish neighbor adjacencies.
C. It sends a multicast query packet to all adjacent neighbors requesting available routing paths to the destination network.
A router is running three routing processes: RIP, OSPF, and EIGRP, each configured with default characteristics. Each process learns a route to the same remote network. If there are no static routes to the destination and none of the routes were redistributed, which route will be placed in the IP routing table?
A. the route learned through EIGRP
B. the route learned through OSPF
C. the route learned through RIP
D. the route with the lowest metric
E. all three routes with the router load balancing
A. the route learned through EIGRP
Which two are advantages of static routing when compared to dynamic routing? (Choose two.)
A. Configuration complexity decreases as network size increases.
B. Security increases because only the network administrator may change the routing table.
C. Route summarization is computed automatically by the router.
D. Routing tables adapt automatically to topology changes.
E. An efficient algorithm is used to build routing tables, using automatic updates.
F. Routing updates are automatically sent to neighbors.
G. Routing traffic load is reduced when used in stub network links.
B. Security increases because only the network administrator may change the routing table.
G. Routing traffic load is reduced when used in stub network links.
What are two drawbacks of implementing a link-state routing protocol? (Choose two.)
A. the sequencing and acknowledgment of link-state packets
B. the requirement for a hierarchical IP addressing scheme for optimal functionality
C. the high volume of link-state advertisements in a converged network
D. the high demand on router resources to run the link-state routing algorithm
E. the large size of the topology table listing all advertised routes in the converged network
B. the requirement for a hierarchical IP addressing scheme for optimal functionality
D. the high demand on router resources to run the link-state routing algorithm
Which parameter would you tune to affect the selection of a static route as a backup, when a dynamic protocol is also being used?
A. hop count
B. administrative distance
C. link bandwidth
D. link delay
E. link cost
B. administrative distance
Which statements are true about EIGRP successor routes? (Choose two.)
A. A successor route is used by EIGRP to forward traffic to a destination.
B. Successor routes are saved in the topology table to be used if the primary route fails.
C. Successor routes are flagged as ‘active’ in the routing table.
D. A successor route may be backed up by a feasible successor route.
E. Successor routes are stored in the neighbor table following the discovery process.
A. A successor route is used by EIGRP to forward traffic to a destination.
D. A successor route may be backed up by a feasible successor route.
A network administrator is troubleshooting an EIGRP problem on a router and needs to confirm the IP addresses of the devices with which the router has established adjacency. The retransmit interval and the queue counts for the adjacent routers also need to be checked. What command will display the required information?
A. Router# show ip eigrp adjacency
B. Router# show ip eigrp topology
C. Router#show ip eigrp interfaces
D. Router#show ip eigrp neighbors
D. Router#show ip eigrp neighbors
Refer to the exhibit. From R1, a network administrator is able to ping the serial interface of R2 but, unable to ping any of the subnets attached to RouterB.
Based on the partial outputs in the exhibit, what could be the problem?
A. EIGRP does not support VLSM.
B. The EIGRP network statements are incorrectly configured.
C. The IP addressing on the serial interface of RouterA is incorrect.
D. The routing protocol has summarized on the classful boundary.
E. EIGRP has been configured with an invalid autonomous system number.
D. The routing protocol has summarized on the classful boundary.
Refer to the exhibit. A packet with a source IP address of 192.168.2.4 and a destination IP address of 10.1.1.4 arrives at the AcmeB router. What action does the router take?
A. forwards the received packet out the Serial0/0 interface
B. forwards a packet containing an EIGRP advertisement out the Serial0/1 interface
C. forwards a packet containing an ICMP message out the FastEthemet0/0 interface
D. forwards a packet containing an ARP request out the FastEthemet0/1 interface
C. forwards a packet containing an ICMP message out the FastEthemet0/0 interface
A router receives information about network 192.168.10.0/24 from multiple sources.
What will the router consider the most reliable information about the path to that network?
A. an OSPF update for network 192.168.0.0/16
B. a static route to network 192.168.10.0/24
C. a static route to network 192.168.10.0/24 with a local serial interface configured as the next hop
D. a RIP update for network 192.168.10.0/24
E. a directly connected interface with an address of 192.168.10.254/24
F. a default route with a next hop address of 192.168.10.1
E. a directly connected interface with an address of 192.168.10.254/24
Refer to the exhibit. The company uses EIGRP as the routing protocol. What path will packets take from a host on 192.168.10.192/26 network to a host on the LAN attached to router R1?
R3# show ip route
Gateway of last resort is not set
192 168.20.0/24 is variably subnetted, 6 subnets, 2 masks
D 192.168.20.64/26 [90/2195456] via 192.168.20.9, 00:03:31, Serial0/0
D 192.168.20.0/30 [90/2681856] via 192.168.20.9, 00:03:31, Serial0/0
C 192.168.20.4/30 is directly connected, Serial0/1
C 192.168.20.8/30 is directly connected, Serial0/0
C 192.168.20.192/26 is directly connected, FastEthernet0/0
D 192.168.20.128/26 [90/2195456] via 192.168.20.5,00:03:31, Serial0/1
A. The path of the packets will be R3 to R2 to R1
B. The path of the packets will be R3 to R1 to R2
C. The path of the packets will be both R3 to R2 to R1 and R3 to R1
D. The path of the packets will be R3 to R1
D. The path of the packets will be R3 to R1
Which statement describes an EIGRP feasible successor route?
A. primary route, added to the routing table
B. backup route, added to the routing table
C. primary route, added to the topology table
D. backup route, added to the topology table
D. backup route, added to the topology table
Refer to the exhibit. Which three EIGRP routes will be present in the router R4’s routing table? (Choose three.)
A. 172.16.1.0/24
B. 10.1.10.0/30
C. 10.0.0.0/8
D. 10.1.11.0/30
E. 172.16.0.0/16
F. 192.168.1.0/24
C. 10.0.0.0/8
E. 172.16.0.0/16
F. 192.168.1.0/24
Refer to the exhibit. If the router R1 returns the given output and has not had its router ID set manually, what address will EIGRP use as its router ID?
A. 192.168.1.2
B. 172.16.4.1
C. 192.168.10.2
D. 1.1.1.1
D. 1.1.1.1
Refer to the exhibit. What address is a feasible successor?
A. 172.16.4.0
B. 10.1.4.4
C. 10.1.2.2
D. 172.16.3.0
C. 10.1.2.2
Refer to the topology. Your company has connected the routers R1. R2. and R3 with serial links. R2 and R3 are connected to the switches SW1 and SW2, respectively.
SW1 and SW2 are also connected to the routers R4 and R5. The EIGRP routing protocol is configured. You are required to troubleshoot and resolve the EIGRP issues between the various routers. Use the appropriate show commands to troubleshoot the issues.
The loopback interfaces on R4 with the IP addresses of 10.4.4.4 /32, 10.4.4.5/32.
And 10.4.4.6/32 are not appearing in the routing table of R5 Why are the interfaces missing?
A. The interfaces are shutdown, so they are not being advertised.
B. R4 has been incorrectly configured to be in another AS, so it does not peer with R5.
C. Automatic summarization is enabled, so only the 10.0.0.0 network is displayed.
D. The loopback addresses haven’t been advertised, and the network command is missing on R4.
B. R4 has been incorrectly configured to be in another AS, so it does not peer with R5.
Which two statements are characteristics of a distance vector routing protocol? (Choose two.)
A. Each router has its own view of the topology.
B. Updates are periodic and include the entire routing table.
C. Routing updates are sent only after topology changes.
D. Convergence is usually faster than with link state protocols.
E. RIP is an example of distance vector routing protocols.
F. The protocol can be useful in hub-and-spoke and hierarchical networks.
B. Updates are periodic and include the entire routing table.
E. RIP is an example of distance vector routing protocols.
Which pairing reflects a correct protocol-and-metric relationship?
A. EIGRP and link cost
B. OSPF and number of hops and reliability
C. RIPv2 and number of hops
D. IS-IS and delay and reliability
C. RIPv2 and number of hops
Refer to the graphic and routing table for router R1. Based on the output of the R1# show ip route command and the information presented in the graphic, which of the following is a potential routing problem?
A. the use of summarization for discontiguous networks
B. the use of CIDR with a routing protocol that does not support it
C. the use of VLSM with a routing protocol that does not support it
D. the use of the no auto-summary command with a protocol that does not support summarization
E. the use of the ip route 0.0.0.0 0.0.0.0 command with a routing protocol that does not support it
A. the use of summarization for discontiguous networks
Drag and Drop Question
Drag the description on the left to the routing protocol on the right. (Not all options are used.)
Which EIGRP for IPv6 command can you enter to view the link-local addresses of the neighbors of a device?
A. show ipv6 eigrp 20 interfaces
B. show ipv6 route eigrp
C. show ipv6 eigrp neighbors
D. show ip eigrp traffic
C. show ipv6 eigrp neighbors
What are two drawbacks of implementing a link-state routing protocol? (Choose two.)
A. the sequencing and acknowledgment of link-state packets
B. the high volume of link-state advertisements in a converged network
C. the requirement for a hierarchical IP addressing scheme for optimal functionality
D. the high demand on router resources to run the link-state routing algorithm
E. the large size of the topology table listing all advertised routes in the converged network
C. the requirement for a hierarchical IP addressing scheme for optimal functionality
D. the high demand on router resources to run the link-state routing algorithm
