1 What is a routing loop?
a packet bouncing back and forth between two loopback interfaces on a router
a condition where a return path from a destination is different from the outbound path forming a "loop"
* a condition where a packet is constantly transmitted within a series of routers without ever reaching its intended destination
the distribution of routes from one routing protocol into another
2 Which of the following methods does split horizon use to reduce incorrect routing information?
Routing updates are split in half to reduce the update time.
* Information learned from one source is not distributed back to that source.
New route information must be learned from multiple sources to be accepted.
The time between updates is split in half to speed convergence.
New route information is suppressed until the system has converged.
3 A network administrator is evaluating RIP versus EIGRP for a new network. The network will be sensitive to congestion and must respond quickly to topology changes.
What are two good reasons to choose EIGRP instead of RIP in this case? (Choose two.)
EIGRP uses periodic updates.
* EIGRP only updates affected neighbors.
EIGRP uses broadcast updates.
* EIGRP updates are partial.
EIGRP uses the efficient Bellman-Ford algorithm.
4
What actions will occur after RouterA loses connectivity to network 114.125.16.0?
(Choose two.)
* RouterB will include network 123.92.76.0 and 136.125.85.0 in its update to RouterA.
During the next update interval, RouterB will send a RIP update out both ports that includes the inaccessible network.
During the next update interval, RouterC will send an update to RouterB stating that network 114.125.16.0 is accessible in 2 hops.
* Router C will learn of the loss of connectivity to network 114.125.16.0 from RouterB.
RouterB will include network 123.92.76.0 and 136.125.85.0 in its update to RouterC.
5 Which of the following statements are correct about RIP?
uses a broadcast to update all other routers in the network every 60 seconds uses a multicast address to update other routers every 90 seconds
* will send out an update if there is a failure of a link
updates only contain information about routes that have changed since last update
6 Which two conditions are most likely to cause a routing loop? (Choose two.)
random jitter
implementation of classful addressing
* inconsistent routing tables
* incorrectly configured static routes a network converging too quickly
7
Refer to the exhibit. What path will packets from the 192.168.1.0/24 network travel to reach the 10.0.0.0/8 network if RIP is the active routing protocol?
The path will be router A -> router B -> router C -> router E.
* The path will be router A -> router D -> router E.
Router A will load balance between the router A -> router D -> router E and router A ->
router B -> router C -> router E paths.
Packets will alternate paths depending on the order they arrive at router A.
8 What is the purpose of the TTL field in the IP header?
used to mark routes as unreachable in updates sent to other routers
prevents regular update messages from reinstating a route that may have gone bad prevents a router from advertising a network through the interface from which the update came
* limits the time or hops that a packet can traverse through the network before it should be discarded
defines a maximum metric value for each distance vector routing protocol by setting a maximum hop count
9 Which of the following can exist in a distance vector network that has not converged?
(Choose three.)
* routing loops
* inconsistent traffic forwarding
no traffic forwarding until system converges
* inconsistent routing table entries
routing table updates sent to wrong destinations
10 What does the RIP holddown timer do?
ensures an invalid route has a metric of 15
prevents a router from sending any updates after it has introduced a routing loop into the network
ensures every new route is valid before sending an update
* instructs routers to ignore updates, for a specified time or event, about possible inaccessible routes
11
Refer to the exhibit. If all routers are using RIP, how many rounds of updates will occur before all routers know all networks?
1 2
* 3 4 5 6
12 Three routers running a distance-vector routing protocol lost all power, including the battery backups. When the routers reload, what will happen?
They will share all routes saved in NVRAM prior to the power loss with their directly connected neighbors.
They will multicast hello packets to all other routers in the network to establish neighbor adjacencies.
* They will send updates that include only directly connected routes to their directly connected neighbors.
They will broadcast their full routing table to all routers in the network.
13 Which two statements describe EIGRP? (Choose two.)
EIGRP can be used with Cisco and non-Cisco routers.
* EIGRP sends triggered updates whenever there is a change in topology that influences the routing information.
EIGRP has an infinite metric of 16.
* EIGRP sends a partial routing table update, which includes just routes that have been changed.
EIGRP broadcasts its updates to all routers in the network.
14
The graphic shows a network that is configured to use RIP routing protocol. Router2 detects that the link to Router1 has gone down. It then advertises the network for this link with a hop count metric of 16. Which routing loop prevention mechanism is in effect?
split horizon error condition hold-down timer
* route poisoning count to infinity
15 What metric does the RIP routing protocol consider to be infinity?
0 15
* 16 224 255
16 Which two statements are true regarding the function of the RIPv1 routing updates?
(Choose two).
updates are broadcast only when there are changes to the topology
* updates are broadcast at regular intervals broadcast are sent to 0.0.0.0
* broadcasts are sent to 255.255.255.255 updates contain the entire network topology only changes are included in the updates
17 Which three routing protocols are distance vector routing protocols? (Choose three).
* RIPv1
* EIGRP OSPF IS-IS
* RIPv2
18
Refer to the exhibit. The routers in this network are running RIP. Router A has not received an update from Router B in over three minutes. How will Router A respond?
The Holddown timer will wait to remove the route from the table for 60 seconds.
* The Invalid timer will mark the route as unusable if an update has not been received in 180 seconds.
The Update timer will request an update for routes that were learned from Router B.
The Hello timer will expire after 10 seconds and the route will be flushed out of the routing table.
19 What does a router running RIP do first with a new route that is received from an
advertisement?
* places it immediately in the routing table
adjusts the metric for the new route to show the added distance for the route advertises this route out all other interfaces except the one that it came in on sends a ping packet to verify that the path is a feasible route
20 Which event will cause a triggered update?
an update routing timer expires a corrupt update message is received
* a route is installed in the routing table the network is converged
21 Which statement is true regarding cisco’s RIP_JITTER variable?
It prevents the synchronization of routing updates by buffering the updates as they leave the router interfaces.
* It prevents the synchronization of routing updates by subtracting a random length of time ranging from 0% to 15% of the specified interval time from the next routing update interval.
It prevents the synchronization of routing updates by causing the router to skip every other scheduled update time.
It prevents the synchronization of routing updates by forcing the router to listen when its time for other updates on the lines before sending its update.
Chapter 5: RIPv1
1
Refer to the exhibit. The network that is shown is running RIPv1. The 192.168.10.0/24 network was recently added and will only contain end users. What command or set of commands should be entered on Router1 to prevent RIPv1 updates from being sent to the end user devices on the new network while still allowing this new network to be advertised to other routers?
Router1(config-router)# no router rip
Router1(config-router)# network 192.168.10.0 Router1(config-router)# no network 192.168.10.0
* Router1(config-router)# passive-interface fastethernet 0/0 Router1(config-router)# passive-interface serial 0/0/0
2. The following line was displayed in the output of the show ip route command.
R 192.168.3.0/24 [120/3] via 192.168.2.2, 00:00:30, Serial0/0
What is the value of the routing metric?
* 3 12 20 30 120
3. Which of the following is considered a limitation of RIP v1?
* RIP v1 does not send subnet mask information in its updates.
RIP v1 is not widely supported by networking hardware vendors.
RIP v1 consumes excessive bandwidth by multicasting routing updates using a Class D address.
RIP v1 requires enhanced router processors and extra RAM to function effectively.
RIP v1 does not support load balancing across equal-cost paths.
RIP v1 authentication is complicated and time-consuming to configure.
4
Refer to the exhibit. The Ethernet interface on Router2 goes down and the administrator notices that the route is still in the Router1 routing table. How much longer will Router1 keep the down network in its routing table before marking it as possibly down?
30 seconds 90 seconds
* 155 seconds 180 seconds 255 seconds
5
Refer to the exhibit. Router1 is running RIPv1. What command was entered into Router1 to configure the gateway of last resort?
no auto-summary
ip default-network 0.0.0.0 ip default-gateway 0.0.0.0
* ip route 0.0.0.0 0.0.0.0 S0/0/1
6. What are three characteristics of the RIPv1 routing protocol? (Choose three.)
supports the use of VLSM
* uses hop count as a metric
* considers a metric of 16 as infinity
has an administrative distance of 110 by default
includes the destination IP address and subnet mask in routing updates
*calculates metrics using the Bellman Ford algorithm
7
Which of the following would be the correct command sequence to enable RIP on Router B for all connected networks?
RouterB# router rip
RouterB(router)# network 210.36.7.0 RouterB(router)# network 220.17.29.0 RouterB(router)# network 211.168.74.0
RouterB(config)# router rip
RouterB(config-router)# network 198.16.4.0 RouterB(config-router)# network 211.168.74.0 RouterB(config-router)# network 199.84.32.0
RouterB(config)# configure router rip RouterB(config-router)# network 210.36.7.0
RouterB(config-router)# network 199.84.32.0 RouterB(config-router)# network 211.168.74.0
RouterB(config)# router rip
RouterB(config-router)# network 198.16.4.0 RouterB(config-router)# network 210.36.7.0 RouterB(config-router)# network 211.168.74.0
* RouterB(config)# router rip
RouterB(config-router)# network 198.16.4.0 RouterB(config-router)# network 210.36.7.0 RouterB(config-router)# network 220.17.29.0
8. What is the default update period in seconds for the RIP routing protocol?
10 12 15 20
* 30 60
9
Refer to the exhibit. What can be concluded from the routing table output of router B?
A static default route has been configured on B.
* The default-information originate command has been entered on A.
All traffic that is destined for 192.168.1.1 will be sent to address 0.0.0.0.
Hosts on the 10.16.1.0/27 network have 192.168.1.1 configured as the default gateway address.
10
Refer to the exhibit. A network consists of multiple routers. What can be verified when the show ip protocols command is issued on one of the routers in the network?
whether all routes in the network have been properly added to the routing table
* routing protocol configuration in use for IP on this router
operational status of routing protocols in use on all routers in the network routing metric of each network that is listed in the routing table
11
Refer to the exhibit. All routers are configured with valid interface addresses in the indicated networks and are running RIPv1. The network is converged. Which routes are present in the routing tables?
All routers have all routes in their routing table.
All routers have all /30 routes, but do not have /24 routes in their routing table.
* All routers have all /30 routes. Routers A and E also have some of the /24 routes in their routing table.
All routers have all /30 routes. Routers B and D also have some of the /24 routes in their routing table.
Routers A and E have all routes. Routers B and D have only /30 routes in their routing table.
Routers A and E have only /24 routes. Routers B and D have only /30 routes in their routing table.
12. Which two statements are true regarding the characteristics of RIPv1? (Choose two).
It is a distance vector routing protocol.
It advertises the address and subnet mask for routes in routing updates.
The data portion of a RIP message is encapsulated into a TCP segment.
* The data portion of a RIP message is encapsulated into a UDP segment.
* It broadcasts updates every 15 seconds.
It allows a maximum of 15 routers in the routing domain.
13. Which command or set of commands will stop the RIP routing process?
RouterB(config)# router rip RouterB(config-router)# shutdown RouterB(config)# router rip
RouterB(config-router)# network no 192.168.2.0
* RouterB(config)# no router rip RouterB(config)# router no rip
14
Refer to the exhibit. All routers in the exhibit are running RIP v1. The network
administrator issues the show ip route command on router A. What routes would appear in the routing table output if the network is converged? (Choose two).
* R 192.168.2.0/24 [120/1]
C 192.168.2.0/24 [120/1]
R 10.10.3.0/24 [120/0]
C 10.10.3.0/24 [120/1]
* R 10.10.1.0/24 [120/2]
R 10.10.1.0/24 [120/3]
15. Which command will display RIP activity as it occurs on a router?
* debug ip rip show ip route show ip interface show ip protocols debug ip rip config show ip rip database
16
Refer to the output from the show ip route command. What can be concluded from the output of this router command?
A preferred route to the destination has not been set.
* There are two equal cost paths to network 1.0.0.0.
Both interfaces are being used equally to route traffic.
A variance must be set to load-balance across multiple paths.
17.
Refer to the exhibit. Router1 and Router2 are running the RIPv1 protocol. The network administrator configures the command network 10.1.0.0 on Router1. What network will Router1 advertise to Router2?
10.1.0.0/16 10.1.0.0/8 10.0.0.0/16
* 10.0.0.0/8
18.
Refer to the exhibit. Pings between the serial interfaces of the routers are successful.
Hosts on each LAN can ping the Fa0/0 interface of the router to which they are directly connected through the switch. However, pings between hosts on the 10.1.1.0/24 and 10.1.2.0/24 networks are unsuccessful. What is a likely cause of this problem?
The Fa0/0 interface on R1 is configured as a passive interface.
The Fa0/0 interfaces on each router is shutdown.
* RIP is configured incorrectly on R1.
Automatic summarization is preventing the routing updates from being forwarded.
The network has not converged and R2 must wait 12 more seconds before receiving a full routing table update from R1.
19. What will happen if an interface IP address is entered for the address portion of the network command in a RIPv1 configuration instead of a network address?
The router will reject the command.
A route to the host address will be added to outgoing RIP updates.
A route to the host address will be added to the routing table.
* All interfaces in the same classful network as the configured address will be included in the RIPv1 routing process.
20.
Refer to the exhibit. All routers that are shown are running the RIP routing protocol. All unknown IP traffic must be forwarded to the ISP. What router or set of routers are recommended to have both a default route and the default-information originate command issued to implement this forwarding policy?
only Router1
* only the gateway router all routers in the network
only the routers with LANs needing Internet access