RIP Version 1 (RIPv1)

To configure RIP routing turn on the protocol with the router rip command and tell it which networks to advertise.

RIP routing example

RouterA Configuration

RIP has an administrative distance of 120. Static routes have an administrative distance of 1 by default and since we currently have static routes configured the routing tables wont be propagated with RIP information. So the first thing we need to do is delete the static routes off each router.

This is done with the no ip route command

RouterA(config)#no ip route 192.168.30.0 255.255.255.0 192.168.20.2RouterA(config)#no ip route 192.168.40.0 255.255.255.0 192.168.20.2 RouterA(config)#no ip route 192.168.50.0 255.255.255.0 192.168.20.2

Once the static routes are deleted we can add RIP1 using the router rip command and the network command. In our router configuration we have to type every directly connected network that RIP will advertise leaving out networks 30, 40 and 50 because its RIP’s job to find them and populate the routing table.

RouterA(config)#router ripRouterA(config-router)#network 192.168.10.0RouterA(config-router)#network 192.168.20.0RouterA(config-router)# ^ZRouterA

That’s it just a few commands easier than static routes! But remember the extra cpu and bandwidth you will consume.

RIP, RIPv2, and IGRP use classful addresses when they configure the network address because of this all subnet masks must be the same on all devices in the network classful routing.

To clarify this say your using a class B network address of 172.16.0.0/24 with subnets 172.16.10.0, 172.16.20.0, and 172.16.30.0, In this case you would type in only the classful network address of 172.16.0.0 and let RIP, RIPv2 and IGRP find the subnets for the routing table.

RIPv1 uses only classful routing which means that all devices in the network must use the same subnet mask. This is because RIPv1 doesn’t send updates with subnet mask information. RIPv2 provides prefix routing and does send subnet mask info with the route updates. This is called classless routing.

Configuring RIP

To configure RIP routing

enableconfig tRouter(config)#router ripnow add all directly connected networks using a classful address ie if network 10.1.1.0 is directly connected the command would be network 10.0.0.0

Router(config-router)#network 10.0.0.0Router(config-router)# ˆZRouter#

The Routing Information Protocol (RIP) is an old but commonly used IGP created for use in small, networks. It is a classical distance-vector routing protocol.

The metric that RIP uses to rate the value of different routes is the hop count. The hop count is the number of routers that can be traversed in a route. A directly connected network has a metric of zero, an unreachable network has a metric of 16. This small range of metrics makes RIP unsuitable as a routing protocol for large networks. If the router has a default network path, RIP advertises a route that links the router to the pseudonetwork 0.0.0.0. The network 0.0.0.0 does not exist; RIP treats 0.0.0.0 as a network to implement the default routing feature.

To configure RIP, perform the following tasks, starting in global configuration mode:

RouterB Configuration

To configure RIP on RouterB we need to remove the two static routes once there are no routes in the routing table with a better administrative distance than 120, we can add RIP. RouterB has 3 directly connected networks and we want RIP to advertise them all.

RouterB#config tRouterB(config)#no ip route 192.168.10.0 255.255.255.0 192.168.20.1RouterB(config)#no ip route 192.168.50.0 255.255.255.0 192.168.40.2RouterB(config)#router ripRouterB(config-router)#network 192.168.20.0RouterB(config-router)#network 192.168.30.0RouterB(config-router)#network 192.168.40.0RouterB(config-router)# ˆZRouterB#

RouterC Configuration

We’ve already removed the static routes on RouterC as we placed a default route on it. So we need to remove the default route from RouterC. Once it’s gone we can turn on RIP routing for the two directly connected routes.

RouterC#config tRouterC(config)#no ip route 0.0.0.0 0.0.0.0 192.168.40.1RouterC(config)#router ripRouterC(config-router)#network 192.168.40.0RouterC(config-router)#network 192.168.50.0RouterC(config-router)# ˆZRouterC#

It’s important to remember directly connected routes have an administrative distance of 0, static routes have an administrative distance of 1 and RIP has an administrative distance of 120.

Verifying the RIP Routing Tables

show ip route, do show route

This output shows RouterA’s routing table.

RouterA#show ip routeCodes: C – connected etc…

R 192.168.50.0 [120/2] via 192.168.20.2 00:00:23 serial0/0R 192.168.40.0 [120/1] via 192.168.20.2 00:00:23 serial0/0R 192.168.30.0 [120/1] via 192.168.20.2 00:00:23 serial0/0C 192.168.20.0 is directly connected, serial0/0C 192.168.10.0 is directly connected, FastEthernet0/0RouterA#

R means networks were added dynamically using RIP. The [120/1] is the administrative distance of the route (120) and the number of hops to the remote network.

The do command

Starting with IOS v12.3, Cisco added a command that allows us to run configuration stats from within configuration mode (previously they were run in privileged mode)

If you had run tried a show run on a pre-12.3 router from global config we would have got an error

Router(config)#show run ^

% Invalid input detected at ‘^’ marker

But now we can use do show ip route

RouterB#show ip routeCodes: C – connected etc…

R 192.168.50.0 [120/2] via 172.16.40.2 00:00:11 serial0/1C 192.168.40.0 is directly connected, serial0/1C 192.168.30.0 is directly connected, FastEthernet0/0

C 192.168.20.0 is directly connected, serial0/0R 192.168.10.0 [120/1] via 172.16.20.1, 00:00:21, serial0/0RouterB#

RouterC#show ip routeCodes: C – connected etc…Gateway of last resort is not set

C 192.168.50.0 is directly connected, FastEthernet0/0C 192.168.40.0 is directly connected, serial0/0R 192.168.30.0 [120/1] via 192.168.40.1, 00:00:04, serial0/0R 192.168.20.0 [120/1] via 192.168.40.1, 00:00:26, serial0/0R 192.168.10.0 [120/1] via 192.168.40.1, 00:00:21, serial0/0RouterC#

Another show ip route example

The Problem with RIP!

So RIP has worked really well in our little internetwork its not an enterprise solution because it has a maximum hop count of only 15 (16 is deemed unreachable) and it performs full routing table updates every 30 seconds which would wreak havoc in a larger network!

If the routing table had showed [120/15] this means the administrative distance is 120 but the hop count is 15 remember each time a router receives an update from another router it increments the hop count by one for each route.

R 192.168.10.0 [120/15] via 192.168.40.1, 00:00:21, serial0/0

So [120/15] is really bad because the next router that receives the table from the router will just discard the route to the network 192.168.10.0 because the next count would be 16 which is invalid.

Configuring RIP using the SDM

From routing Edit

Select RIP the network number and tick the interfaces you don’t want RIP to be broadcast out of. These are called passive interfaces

RIP Example

Configure Router A, use the network ID of 192.168.164.0/28. The s0/0 interface of Router A will use the last available IP address in the 8th subnet and fa0/0 will use the last available IP address in the 2nd subnet. Do not consider the zero subnet valid.

Answer

/28 = 255.255.255.240 mask256 – 240 = 16 block size in the 4th octet Since we have a block size of 16 our subnets are: (not starting at subnet zero) 16, 32, 48, 64, 80, 96,112,128,144 etc… The 8th subnet for the s0/0 interface is subnet 128 Valid host range is 129 – 142, 143 is the broadcast addressThe 2nd subnet fa0/0 = subnet 32Valid hosts 33 – 46, 47 as broadcast

Configuration on Router A will be

RouterA(config)#interface s0/0 RouterA(config-if)#ip address 192.168.164.142 255.255.255.240RouterA(config-if)#no shutdownRouterA(config-if)#interface fa0/0 RouterA(config-if)#ip address 192.168.164.46 255.255.255.240RouterA(config-if)#no shutdownRouterA(config-if)#router ripRouterA(config-router)#network 192.168.164.0RouterA(config-router)#^ZRouterA#

Here we added 2 subnets to the Router A router using a singe classful network statement under RIP.

RIP Timers

Route update timer Sets the interval (30s) between periodic routing updates in which the router sends a complete copy of its routing table out to all neighbors.

Route invalid timer The length of time that must elapse (180s) before a router determines that the route is invalid when this happens the router will send out updates to all its neighbors letting them know the route is invalid.

Holddown timer This sets the amount of time during which routing information is suppressed. Routes will enter into the holddown state when an update packet is received that indicated the route is reachable. This continues either until an update packet is received with a better metric or until the holddown timer expires for RIP the default is 180s.

Route flush timer Sets the time between a route becoming invalid and its removal from the routing table (240s)

Holding down RIP Propergations

You probably don’t want your RIP network advertised everywhere on your LAN/WAN no point in advertising over the internet. You can stop unwanted RIP updates from propagating across your LAN/WAN a few ways. The easiest is the passive-interface command. This command prevents RIP update broadcasts from being sent out an interface, but the same interface can still receive RIP updates.

RouterA#config tRouterA(config)#router ripRouterA(config-router)#network 192.168.10.0 RouterA(config-router)#passive-interface serial 0/0

This command stops RIP updates from being propagated out serial interface 0/0, but serial interface 0/0 can still receive RIP updates.

Question

If the passive interface command is enabled on the fa0/0 interface of Router E, which statements are true? (Choose two.) A. Router E will send all routing updates via interface fa0/0. B. Router E will ignore all routing updates learned via interface fa0/0. C. Router E will use routing updates learned via interface fa0/0. D. Router E will not send routing updates via interface fa0/0.

Answer C, D

Router E will use routing updates learned via interface fa0/0. Router E will not send routing updates via interface fa0/0.

QuestionA technician is configuring a router named RouterLon.Why does she use passive-interface command?

A. Allows a routing protocol to forward updates out an interface that is missing its IP address.B. Allows a router to send routing updates on an interface but not receive updates via that interface.C. Allows an interface to remain up without receiving keepalives.D. Allows interfaces to share IP addresses.E. Allows a router to receive routing updates on an interface but not send updates via that interface.

Answer E

ExplanationThe passive-interface command is used to control the advertisement of routing information. The command enables the suppression of routing updates over some interfaces while allowing updates to be exchanged normally over other interfaces.

With most routing protocols, the passive-interface command restricts outgoing advertisements only. However, when used with Enhanced Interior Gateway Routing Protocol (EIGRP), the effect is slightly different. The use of the passive-interface command in EIGRP suppresses the exchange of hello packets between two routers, resulting in the loss of their neighbor relationship. This stops not only routing updates from being advertised, but it also suppresses incoming routing updates.

QuestionYou are concerned about security on your network. You have a router that is connected to the Internet and do not want your RIP updates being sent out this interface that is connected to the Internet. Which command will prevent these updates from going out the interface without using access-lists? A. Passive routesB. Default interfaceC. Passive interfaceD. Route update filtering

Answer C

ExplanationThe passive interface command will prevent the sending of RIP updates.

Incorrect AnswersA. Passive routes as used with IGRP and not RIP.B. Default/static routes will not prevent RIP updates. D. Filtering is most often achieved on a router with an access list.

QuestionYou are using a distance-vector routing protocol at your branch office in Idaho. Because you are using RIP, what can you use to prevent routing loops? (Choose two.)

A. Link-state advertisements (LSAs)B. Spanning-Tree ProtocolC. A shortest path first treeD. Split-horizonE. Hold-down timers

Answers D and E

Split-horizon ensures that updates are not sent back through the interface on which they arrived; this helps prevent loops. Hold-down timers prevent incorrect updates from propagating throughout the network. A is incorrect, as LSAs are used by link-state protocols to announce changes in the network. B is incorrect, as Spanning-Tree Protocol is used in switched environments, not routing protocols. C is incorrect because the SPF tree is used to help decide the best path to the destination.

QuestionWhich of the following can reset a hold-down timer? (Choose three.)

A. When the hold-down timer expires. B. When infinity is finally defined as some maximum number. C. When the router exchanges update summaries at area borders. D. When the router detect faulty LSPs propagating through the internetwork. E. When another update is received indicating a new route with a better metric. F. When another update is received indicating the original route to the network has been restored. G. When the router receives a processing task proportional to the number of links in the internetwork. Answer A, E, F

ExplanationHolddown timers work as follows

When a router receives an update from a neighbor indicating that a previously accessible network is now in accessible, the router marks the route as inaccessible and starts the holddown timer. If an update arrives from the neighboring router with a better metric than originally recorded for the network, the router marks the network as accessible and removes the holddown timer. If at any time before the holddown timer expires an update is received from a different neighboring router with a poorer metric, the update is ignored. Ignoring an update with a poorer metric when the holddown is in effect allows more time for the knowledge to change to propagate through the network. During the holddown period, routes appear in the routing table as possible down. Routers remain in holddown until one of the following events occurs: the holddown expires; another update is received indicating a new route with a better metric; and a flush timer, which is the time a route would be held before being removed, removes the route from the routing table.

Incorrect answersB, C, D and G. None of these situations will remove a holddown timer.

Another RIP example

Configure a simple network with two routers to run RIP. Our network consists of three subnets, 10.0.10.0/24, 10.0.20.0/24, and 10.0.30.0/24, as shown. Our goal is to ultimately have Router A learn about network 10.0.30.0 from Router B, and Router B learn about network 10.0.10.0 from Router A using RIP.

If you’re trying to configure a router to use RIP to exchange routing table information, an important step is to remove any static routes. If you have a static route defined on Router A that provides information on how to get to network 10.0.30.0, any information that Router A receives about network 10.0.30.0 via RIP will be ignored. A static route has an administrative distance of 1, while RIP’s administrative distance is 120. When a route with a higher administrative distance is received, it is ignored.

The command to turn on RIP routing is simple – from global configuration mode, simply issue the command router rip, as shown below.

RouterA(config)#router rip

Notice how the prompt changes, the router rip command makes this router capable of sending and receiving RIP updates. However we have to tell it which network(s) to advertise. In this case, the network we want to advertise is 10.0.0.0. You don’t need to specify either the subnet mask or specific subnet addresses – because RIP is classful it will automatically assume that you meant all networks starting with 10. In order to make RIP announce all of the 10.0.0.0 subnets, enter the network 10.0.0.0 command.

RouterA(config-router)#network 10.0.0.0

That’s literally all it takes to set up RIP. Of course, we’ll also need RIP configured on Router B, which involves following the same steps.

RouterB(config)#router ripRouterB(config-router)#network 10.0.0.0

In order to confirm that RIP is properly exchanging information between our routers, let’s take a look at the routing tables on Router A.

RouterA#show ip routeCodes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGPi - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate defaultU - per-user static route, o - ODRGateway of last resort is not set10.0.0.0/24 is subnetted, 3 subnetsC 10.0.10.0 is directly connected, Ethernet0R 10.0.30.0 [120/1] via 10.0.20.2, 00:00:22, Serial0C 10.0.20.0 is directly connected, Serial0

Notice in the routing table above that Router A learned about network 10.0.30.0 from RIP, as designated by the R at the beginning of the entry. The administrative distance is 120, and the number of hops to reach the network is 1, as designated by the entry [120/1].

Finally, the next-hop address is 10.0.20.2, which is accessible via interface Serial0.An easy way to test whether RIP is working on both routers is a simple ping. If Router A can successfully ping IP address 10.0.30.1, it means that Router B also has a route (learned from RIP) back to network 10.0.10.0.

RouterA#ping 10.0.30.1Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 10.0.30.1, timeout is 2 seconds:!!!!!Success rate is 100 percent (5/5), round-trip min/avg/max = 32/38/48 ms

Remember that many routing protocols are also able to load-balance across multiple paths. RIP can load balance traffic across up to 6 paths, as long as the hop counts to the network in question are equal.

Configuring RIP on a Subinterface

Router2#configure terminal Enter configuration commands, one per line. End with CNTL/Z.Router2(config)#interface Ethernet0Router2(config-if)#ip address 192.168.30.1 255.255.255.0Router2(config-if)#interface Serial0.1Router2(config-subif)#ip address 172.25.2.2 255.255.255.0Router2(config-subif)#exitRouter2(config-router)#router ripRouter2(config-router)#network 172.25.0.0Router2(config-router)#network 192.168.30.0Router2(config-router)#endRouter2#

The Serial0.1 interface in this example has an IP address of 172.25.2.2. So, if you want this interface to take part in RIP route distribution, you just need to include a network statement that includes its address.

Router2(config)#router ripRouter2(config-router)#network 172.25.0.0

If you have other interfaces that are also part of 172.25.0.0/16 on this router, they will take part in RIP as well. It's important to note that RIP network statements work with classful network addresses. Since 172.25.0.0 is a Class B network, the statement network 172.25.0.0 tells the router to include all interfaces in this range. Note, however, that the other address on this router, 192.168.30.1, is part of the Class C network 192.168.30.0/24, which is why we need the second network command. If your router has several addresses that belong to different network classes (for example, 192.168.x.0/24), you have to specify them all separately.

Router2(config)#router ripRouter2(config-router)#network 192.168.1.0Router2(config-router)#network 192.168.2.0Router2(config-router)#network 192.168.3.0

RIP Version 2 (RIPv2

config t Router(config)#router ripRouter(config-router)#version 2Router(config-router)#network 10.0.0.0

Just add version 2

RIPv2 unlike RIPv1 is a classless routing protocol (even though it is configured as classful, like RIPv1 which means that it sends subnet mask information along with the route updates. By sending subnet mask info with updates, RIPv2 can support Variable Length Subnet Masks (VLSMs) as well as the summarisation of network boundaries. In addition RIPv2 can support discontiguous networking.

RouterC(config)#router ripRouterC(config-router)#version 2RouterC(config-router)#network 192.168.40.0RouterC(config-router)#network 192.168.50.0

That’s it just add the command version 2

If two neighboring routers are sending and receiving different versions of RIP, routes will not be properly exchanged.  By default, RIP routers are sending version 1 updates and accepting version 1 and 2 updates.

QuestionBoth routers are configured using RIP v1. Both routers are sending updates about the directly connected routes. R1 can successfully ping the serial interface of R2. The routing table on R1 does not contain any dynamically learned routes from R2, and the routing table on R2 shows no dynamically learned routes from R1. What is the problem?

A. Subnetting is not supported by RIP v1.

B. One of the routers needs a clock rate on the serial interface.

C. CIDR is not supported by RIP v1.

D. VLSM is not supported by RIP v1.

Answer D

VLSM is not supported by RIP v1.

RIP's default behavior is to send version 1 updates only, but to accept both versions 1 and 2.

This is a strange little default, but you better know this! See show ip protocols

R2#show ip protocolsRouting Protocol is "rip"Sending updates every 30 seconds, next due in 6 secondsInvalid after 180 seconds, hold down 180, flushed after 240Outgoing update filter list for all interfaces isIncoming update filter list for all interfaces isRedistributing: ripDefault version control: send version 1, receive any version

RIP version 2 default behavior is to autosummarize routes advertised across classful boundaries. To disable this behavior, run the no auto-summary command under the RIP process.

To hardcode RIP to send and receive only version 1 or version 2, run the appropriate version command under the RIP process.

RIP version 2 supports variable-length subnet masking (VLSM), but you still enter the classful network number under the RIP process.

R1#conf tEnter configuration commands, one per line. End with CNTL/Z.R1(config)#router ripR1(config-router)#version 2R1(config-router)#no auto-summaryR1(config-router)#network 172.10.0.0

To see the routes being advertised in RIP updates and the metrics of these routes,run debug ip rip.

To see these updates immediately after turning the debug on, run clear ip route * to clear the routing table of its dynamic routes.

R1#debug ip ripRIP protocol debugging is onR1#clear ip route *01:16:54: RIP: sending v1 update to 255.255.255.255 via Loopback1 (1.1.1.1)

01:16:54: network 2.0.0.0, metric 201:16:54: network 3.0.0.0, metric 201:16:54: network 172.16.0.0, metric 101:16:54: network 10.0.0.0, metric 201:16:54: RIP: sending v1 update to 255.255.255.255 via Serial0 (172.16.123.1)01:16:54: subnet 172.16.123.0, metric 101:16:54: network 1.0.0.0, metric 101:16:54: network 2.0.0.0, metric 201:16:54: network 3.0.0.0, metric 201:16:54: network 10.0.0.0, metric 2

If you want to see only a certain protocol route from the entire routing table, run theshow ip route followed by the protocol or route type (static, for example).

R1#show ip route ripR 2.0.0.0/8 [120/1] via 172.16.123.2, 00:00:26, Serial0R 3.0.0.0/8 [120/1] via 172.16.13.2, 00:00:09, Serial1[120/1] via 172.16.123.3, 00:00:09, Serial0R 10.0.0.0/8 [120/1] via 172.16.13.2, 00:00:09, Serial1[120/1] via 172.16.123.3, 00:00:09, Serial0[120/1] via 172.16.123.2, 00:00:26, Serial0

Don't forget to turn your debugs off when you're done! To turn all debugs off at once, run undebug all. To turn off individual debugs, run the command no debug followed by the type of debug you want to turn off - no debug ip rip, for example.

R1#undebug allAll possible debugging has been turned off

Remember how to verify RIP routing. The show ip route command provides the routing table. R= RIP found route. The debug ip rip command shows rip updates being sent and received on the router.

Another example

Note RIPv2 is classless and works in VLSM and discontiguous networks

Multicasting

To reduce unnecessary load on hosts that are not listening to RIPv2 messages, an IP multicast address is used for periodic broadcast messages. The IP multicast address is 224.0.0.9.

Troubleshooting RIP

Show ip protocols

provides information about the interfaces on which RIP is configured, the sources of routing information, and the timer values.

Notice that this router is receiving updates from address 10.1.1.2

The show ip protocols shows we are running RIP for networks 10.0.0.0, 172.16.0.0 Which means a our configuration would be

Router(config)#router ripRouter(config-router)#network 10.0.0.0Router(config-router)#network 172.16.0.0

Also ethernet and serial2 are participating in the RIP network and the neighbor router is 10.1.1.2

Lets also look at the show ip interface brief

From this command we can see that only serial0/0 is in the 10.0.0.0 network.

This means that the router will only send and receive routing updates with the 10.0.0.0 network and will not advertise the 192.168.0.0 network out any interface.

show ip route

Displays the ip routing table. A summary of the route information for specific ip addresses, network masks or protocols.

QuestionWhat can be determined from the line of "show ip route" output shown below R 10.10.10.8 [120/2] via 10.10.10.6, 00:00:25, Serial0/1 (choose two)

A. The ip address 10.10.10.8 is configured on S0/1

B. The 10.10.10.8 network is 2 hops away from this router

C. The next routing update can be expected in 35 seconds

D. This route is using the default administrative distance

E. The ip address 10.10.10.6 is configured on S0/1

Answer B, D

Explanation

R 10.10.10.8 [120/2] via 10.10.10.6, 00:00:25, Serial0/1

B is correct because that is a RIP metric, hop count, it is two hops away. [120/2]D is correct. 120 is the default AD for RIP. [120/2]

This is a RIP update about network 10.10.10.8, with the default RIP AD, and is two hops away. The route is coming on interface s0/1 from a neighbor router with the network address of 10.10.10.6 the next hop.

00:00:25 Specifies the last time the route was updated (in hours:minutes:seconds).

E is incorrect the 10.10.10.6 is next hop and serial0/1 is the local interface used to transmit data to the destination network 10.10.10.8. Data destined for 10.10.10.8 will be placed in the output queue on serial 0/1 the interface through which the destination network can be reached.

debug ip rip, terminal monitor monitor the RIP traffic on your network

The debug ip rip command sends information about routing updates as they are sent and received by the router to the console session. If you are telnetted into the router, use the terminal monitor command to be able to receive the output from the debug commands.

RIP is sending v1 packet to 255.255.255.255 a broadcast out interface serial0/0/01 via 10.1.5.2 this is where RIP v2 would only send a multicast 224.0.0.9

RouterB#debug ip ripRIP protocol debugging is on RouterB#07:12:56 RIP received v1 update from 192.168.40.2 on Serial0/1 07:12:56 192.168.50.0 in 1 hops07:12:56 RIP received v1 update from 192.168.20.1 on Serial0/007:12:56 192.168.10.0 in 1 hops

Note that RIP version 1 is received on RouterB serial0/0 and serial0/1 interfaces this is from RouterA and RouterC. Note split horizon rules stop RouterA and RouterC from advertising back routes that they learned from RouterB

This means that only network 192.168.50.0 is being advertised from RouterC and 192.168.10.0 is being advertised to RouterB from RouterA.

Split horizon exists for a very good reason - routing loop prevention. The rule of split horizon states that a router cannot send an advertisement for a route out the same interface that it came in on. With split horizon activated, a router omits sending routes back to the router it learned them from This help in avoiding a process of mutual deception where two routers tell each other that they can reach destination x via each other.

Split horizon is on by default on all interfaces running RIP, IGRP, and EIGRP.

Split horizon with poisoned reverse a router behaves in the same way as plain split horizon, but instead of not sending information back it sends a route update with a metric of 16 (unreachable) to the router it got the route from.

07:12:58 RIP: sending v1 update to 255.255.255.255 via FastEthernet0/0 (192.168.30.1)07:12:58 subnet 192.168.50.0, metric 107:12:58 subnet 192.168.40.0, metric 107:12:58 subnet 192.168.20.0, metric 107:12:58 subnet 192.168.10.0, metric 107:12:58 RIP: sending v1 update to 255.255.255.255 via FastEthernet0/0 (192.168.20.2)07:12:58 subnet 192.168.50.0, metric 107:12:58 subnet 192.168.40.0, metric 107:12:58 subnet 192.168.30.0, metric 107:12:58 RIP: sending v1 update to 255.255.255.255 via FastEthernet0/0 (192.168.40.1)07:12:58 subnet 192.168.30.0, metric 107:12:58 subnet 192.168.20.0, metric 107:12:58 subnet 192.168.10.0, metric 1

Here split-horizon rules allow only networks 192.168.30.0, 40 and 50 to be advertised to RouterA. RouterB will not advertise the 192.168.10.0 network back to RouterA, nor 192.168.50.0 back to RouterC.

If the metric of a route shows 16, this is a route poison, and the route advertising is unreachable.

In order to gain more information about the actual contents of the RIP traffic moving between systems, use the debug ip rip command. This particular command is like a toggle switch – debugging information that shows the contents of RIP updates sent and received will continue to appear on-screen until you turn it off with the no debug ip rip command.

RouterA#debug ip ripRIP protocol debugging is on

22:48:34: RIP: received v1 update from 10.0.20.2 on Serial022:48:34: 10.0.30.0 in 1 hops22:48:38: RIP: sending v1 update to 255.255.255.255 via Ethernet0 (10.0.10.1)22:48:38: subnet 10.0.20.0, metric 122:48:38: RIP: sending v1 update to 255.255.255.255 via Serial0 (10.0.20.1)22:48:38: subnet 10.0.20.0, metric 1RouterA#no debug ip rip

Note that the debug ip rip command shows the RIP updates both sent and received on a particular interface, along with associated subnet and metric information. Remember than a metric of 16 suggests an unreachable network in RIP.

To close down the debugger

RouterB#undebug all

All possible debugging has been turned offRouterB#

To turn off debugging we can use the undebug all or no debug all or un all command

QuestionYour senior network administrator wants you to monitor the RIP traffic on your network in real time. Which of the following commands would you issue?

A. Show ip routeB. Show processesC. Debug ip ripD. Show ip rip

Answer C

Monitoring in real time requires the use of a debug command. Show commands merely grab a snapshot in time, whereas debug commands are in real time. A is incorrect, as it is a show command. B is incorrect, as it is merely another show command. D is also incorrect, as it uses a show command.

Here from the updates information is sent out about 10.0.0.0, 192.168.1.0 and 172.16.0.0

Both the 10.0.0.0 and 172.16.0.0 network are advertised with a metric of 1 which means their directly connected. 192.168.168.0 is unreachable.

QuestionRouterC does not appear to be receiving RIP updates from RouterB, which command can you enter on RouterC to see if it is receiving these RIP updates? A. Show ip protocols. B. Show ip route rip. C. Debug ip rip. D. Debug ip updates. E. Debug ip transactions. Answer C

ExplanationThe debug debug ip rip command displays information on RIP routing transactions. It would enable us to see if the RIP updates are received. Incorrect AnswersA. The show ip protocol command is used to see if a router is delivering bad routing information. B. This is not a valid command. RIP is not a parameter of show ip route command. D and E are not valid debug commands.

Although you don’t need to know how to do this for the exam, it’s always nice to know how to change the default timers used by a protocol. The command to do so is timers basic, and is issued from the routing protocol configuration level. One important note here – if you do decide to change the timers on one router, you should also change the timers on every router. Otherwise, you’ll be dealing with one very unpredictable network potentially susceptible to routing loops.

RouterA(config)#router ripRouterA(config-router)#timers basic ?<0-4294967295> Interval between updates

RouterA(config-router)#timers basic 30 ?<1-4294967295> InvalidRouterA(config-router)#timers basic 30 180 ?<0-4294967295> HolddownRouterA(config-router)#timers basic 30 180 180 ?<1-4294967295> FlushRouterA(config-router)#timers basic 30 180 180 240

I used the help function to walk through the timers basic command step by step to show you the order of the entries – update, invalid, holddown, and flush. Ultimately, the same command can be used to set IGRP timers.

QuestionYou company has decided to use RIP version 1 as the routing on a Cisco router. What is the command to enable rip as the routing protocol on the company’s router?

A. SET RIPB. SET ROUTER RIPC. RIPD. ROUTER RIP

Answer D

ExplanationThe key characteristics of RIP include: it is a distance vector protocol, hop count is the metric used for path selection, it maximum allowable hop count is 15, it broadcasts it entire routing table every 30 seconds by default and it can be load balanced as many as six equal cost paths (4 paths are the default). To configure RIP not only does the router rip command need to be inputted but also it must be followed by the network command. The network command must be issued for each directly connected network.

QuestionYour company has decided to use IP RIP version 1 as the routing protocol. Which of the following are the commands you can use to configure IP RIP version 1 on your router?

A. Router RIP network 172.16.1.0 network 10.1.0.1

B. Router RIP network 172.16.0.0 network 10.0.0.0

C. Router RIP network 172.16.1.0 172.16.1.1 network 10.1.0.0 10.1.1.1

D. Router RIP network 172.16.1.0 265.255.255.0 Network 10.1.0.0 255.255.0.0

Answer B

Explanation

To enable RIP version 1 not only does the router rip command need to be used but also it must be followed by the network command. The network command must be issued for each directly connected network. The network command must be followed by a valid network address.

Incorrect Answers

A. Is this series of commands the network 10.1.0.1 is not a valid command. C. If 4 networks are directly connected they must have their own network command. D. There is no need to include a subnet mask with a network command.

QuestionYou have been hired as a consultant to troubleshoot the company's network. You issue the debug ip rip command to troubleshooting the rip network. You notice your Ethernet interface 10.1.0.0 shuts down. Which update message is seen in your routers debug ip rip output regarding that network?

A. Subnet 10.1.0.0, metric 0

B. Subnet 10.1.0.0, metric 1

C. Subnet 10.1.0.0, metric 15

D. Subnet 10.1.0.0, metric 16

Answer D

ExplanationRIP (Routing Information Protocol) is a distance vector protocol. RIP uses hope counts as metric. The designers of RIP believed that the protocol was unlikely to be practical for networks with a diameter larger than 15. The maximum hop count is therefore set to 15. In RIP when a network in not reachable then its metric is changed to 16.Incorrect AnswersA. A metric of 0 denotes a directly connected route and indicates that the interface is up. B. This metric indicates that the interface is up and that the destination is reached with a hop count of 1. C. This metric indicates that the interface is up and that the destination is reached with a hop count of 15.

QuestionRouterC does not appear to be receiving RIP updates from RouterB, which command can you enter on RouterC to see if it is receiving these RIP updates? A. Show ip protocols.

B. Show ip route rip.

C. Debug ip rip.

D. Debug ip updates. E. Debug ip transactions.

Answer C

ExplanationThe debug debug ip rip command displays information on RIP routing transactions. It would enable us to see if the RIP updates are received.Incorrect Answers:A. The show ip protocol command is used to see if a router is delivering bad routing information. B. This is not a valid command. RIP is not a parameter of show ip route command. D and E. These are not valid debug commands.

QuestionYou need to install RIP as the routing protocol of your network. Which of the following shows the correct prompt and command to install RIP as the routing protocol? (Choose one)

A. Router# rip. B. Router rip. C. Router (Config)# rip. D. Router (Config)# router rip. Answer D

ExplanationIn order to configure RIP as the routing protocol you need to ensure that you are in the route configuration mode and that you use the command router rip. A. This is both the wrong mode and command. B. This is both the wrong mode and command. C. This is the proper mode but the wrong command.

QuestionYou would like to configure IP RIP on your Cisco Router. Which of the following steps below are required to install IP RIP? (Choose two)

A. Specify the routing protocol.

B. Configure static Rip routes. C. Specify directly connected subnets. D. Specify directly connected networks.

Answer A, D

ExplanationIn enable a router with RIP it takes two basic steps: select the routing protocol and identify the networks that the router is directly connected to. These steps are achieved with the commands router rip and network.

Incorrect AnswersB. There is no such thing as a static RIP route.C. With RIP you specify the directly connected networks, not the directly subnets.

QuestionYou need to install RIP on your router. Which command enables directly connected network 131.107.10.0 to be used by RIP? A. Router(Config)# rip 131.107.10.0

B. Router(Config-router)# rip 131.107.10.0 C. Router(Config-router)# network 131.107.10.0

D. Router(Config-router)# network 131.107.0.0 Answer D

ExplanationThe network command allows the routing process to identify the interfaces will participate in the sending and receiving of messages. Incorrect AnswersA and B. These are not valid commands. In addition, A is in the wrong mode.C. This is the wrong network number. The 131.107.10.0 is a Class B subnet, using a default mask of 255.255.0.0.

QuestionThe RIP network shown in the exhibit has been fully operational for two days. Each routing table is complete.

Which networks will be included in the next routing update from the Testking1 router to the Testking3 router?

A. A,B,C,D,E,F

B. A,C

C. A,B,C,D D. B,D

E. D,E,F

F. A,B,C

Answer F

ExplanationTestking3 gets routing update from Testking1 with the following informationNetwork A, metric 1 Network B, metric 1 Network C, metric 2

Incorrect AnswersA. Not A because of split horizon. It is never useful to send information about a route back in the direction from which the original update came. B. Not B because it is missing one routing update information (Network B). C, D, E: Not C, D & E because you don't get a routing update for your directly connected network (Network D).

QuestionA technician is configuring a routeWhy does she use passive-interface command?

A. Allows a routing protocol to forward updates out an interface that is missing its IP address.B. Allows a router to send routing updates on an interface but not receive updates via that interface.C. Allows an interface to remain up without receiving keepalives.D. Allows interfaces to share IP addresses.E. Allows a router to receive routing updates on an interface but not send updates via that interface.

Answer E

ExplanationThe passive-interface command is used to control the advertisement of routing information. The command enables the suppression of routing updates over some interfaces while allowing updates to be exchanged normally over other interfaces.

With most routing protocols, the passive-interface command restricts outgoing advertisements only. However, when used with Enhanced Interior Gateway Routing Protocol (EIGRP), the effect is slightly different. This document demonstrates that use of the passive-interface command in EIGRP suppresses the exchange of hello packets between two routers, resulting in the loss of their neighbor relationship. This stops not only routing updates from being advertised, but it also suppresses incoming routing updates. This document also discusses the configuration required in order to allow the suppression of outgoing routing updates, while allowing incoming routing updates to be learnt normally from the neighbor.

QuestionRtrA#debug ip ripRip protocol debugging is onRtrA#1d05h: RIP: sending v1 update to 255.255.255.255 via FastEthernet0/0(172.16.1.1)1d05h: RIP: build update entries1d05h: network 10.0.0.0 metric 1

1d05h: network 192.168.1.0 metric 21d05h: RIP: sending v1 update to 255.255.255.255 via Serial0/0 (10.0.8.1)1d05h: RIP: build update entries1d05h: network 172.16.0.0 metric 1RtrA#1d05h: RIP: received v1 update from 10.0.15.2 on Serial0/01d05h: 192.168.1.0 in 1 hops1d05h: 192.168.0 in 16 hops (inaccessible)

Which of the following are true regarding the command output shown in the display? (Choose two)

A. There are at least two routers participating in the RIP process.B. A ping to 192.168.168.2 will be successful.C. A ping to 10.0.15.2 will be successful.D. RtrA has three interfaces participating in the RIP process.

Answer A, C

QuestionRouterTK#show ip routeCodes: C-connected, s-static, I –IGRP, R –RIP, M –mobile, B –BGP, D –EIGRP, EX – EIGRP external, O – OSPF, IA –OSPF inter area, EI –OSPF external type 1, E2 –OSPF external type 2, E –EGP, i –IS-IS, L1 –IS-IS level-1, L2 –IS-IS level-2, * -candidate default, U – per-user static route

Gateway of last resort is not set

R 202.30.8.0 /24[120/1] via 202.30.2.2, 00:00:16, Serial 0C 202.30.9.0 /24 is directly connected, Serial 1R 202.30.10.0 /24 is possibly down, routing via 202.30.9.1, Serial 1R 202.30.11.0 /24 is possibly down, routing via 202.30.9.1, Serial 1C 202.30.1.0 /24 is directly connected, Ethernet 0C 202.30.2.0 /24 is directly connected, Serial 0R 202.30.3.0 /24 [120/1] via 202.30.2.2, 00:00:17, Serial 0R 202.30.4.0 /24 [120/15/ via 202.30.2.2, 00:00:17, Serial 0R 202.30.5.0 /24 [120/15] via 202.30.2.2, 00:00:17, Serial 0R 192.158.6.0 /24 [120/15] via 202.30.2.2, 00:00:17, Serial 0R 202.30.7.0 /24 [120/1] via 202.30.2.2, 00:00:17, Serial 0

You are troubleshooting a router with default settings. You are concerned about the 202.30.10.0 and 202.30.11.0 routes. In particular you are interested how long they will be kept in the routing table. What would be the maximum time these routes would be kept in the routing table?

A. 30 secondsB. 60 secondsC. 240 secondsD. 360 secondsE. 630 seconds

Answer C

Explanation: The Rs on the 202.30.10.0 and 202.30.11.0 lines (see below) indicates that the routes were learned from the RIP protocol.

R 202.30.10.0 /24 is possibly down, routing via 202.30.9.1, Serial 1R 202.30.11.0 /24 is possibly down, routing via 202.30.9.1, Serial 1

The hold down timer for RIP is 180 sec. The flush timer for RIP is 240 sec.

QuestionRouterTK#show ip routeCodes: C-connected, s-static, l –IGRP, R –RIP, M –mobile, B –BGP, D –EIGRP, EX – EIGRP external, O – OSPF, IA –OSPF inter area, EI –OSPF external type 1, E2 –OSPF external type 2, E –EGP, i –IS-IS, L1 –IS-IS level-1, L2 –IS-IS level-2, * -candidate default, U – per-user static route

Gateway of last resort is not set

R 202.30.8.0 /24[120/1] via 202.30.2.2, 00:00:10, Serial 0C 202.30.9.0 /24 is directly connected, Serial 1R 202.30.10.0 /24 [120/7] via 202.30.9.1, 00:00:02, Serial 1R 202.30.11.0 /24 [120/7] via 202.30.9.1, 00:00:03, Serial 1C 202.30.1.0 /24 is directly connected, Ethernet 0C 202.30.2.0 /24 is directly connected, Serial 0R 202.30.3.0 /24 [120/1] via 202.30.2.2, 00:00:10, Serial 0R 202.30.4.0 /24 [120/15/ via 202.30.2.2, 00:00:10, Serial 0R 202.30.5.0 /24 [120/15] via 202.30.2.2, 00:00:10, Serial 0R 202.30.6.0 /24 [120/15] via 202.30.2.2, 00:00:10, Serial 0R 202.30.7.0 /24 [120/1] via 202.30.2.2, 00:00:10, Serial 0

You examine the routing table of your router This routing table will be send to neighbouring routers via broadcasts. Some routes might be discarded and not entered in to the routing tables of the neighbouring RIP routers. Which of the following routes would be discarded in this way?

A. R 202.30.8.0/24 [120/1] via 202.30.2.2, 00:00:10, Serial0B. R 202.30.11.0/24 [120/7] via 202.30.9.1, 00:00:03, Serial1C. C 202.30.1.0/24 is directly connected, Ethernet0D. R 202.30.5.0/24 [120/15] via 202.30.2.2, 00:00:10, Serial0

Answer D

RIP has the maximum hop count of 15. This route already has a hop count of 15 and adding one would make it unreachable (see below). This route will be discarded.R 202.30.5.0/24 [120/15] via 202.30.2.2, 00:00:10, Serial0

QuestionLook at the configuration below and identify the true statement R3#conf t

Enter configuration commands one per line end with cntl/zR3(config)#router ripR3(config-router)#network 172.12.0.0

A. A subnet mask must follow 172.12.0.0B. The RIP version number must follow 172.12.0.0C. A wildcard mask must follow 172.12.0.0D. Nothing should follow 172.12.0.0

Answer D

ExplanationA. RIPv1 does not understand VLSM while RIPv2 does however it doesn’t matter which

version of RIP you run the subnet mask does not go here B. Only RIPv1 has been configured C. RIP doesn’t use wildcard masks

Question Your company has decided to use IP RIP version 1 as the routing protocol. Which of the following are the commands you can use to configure IP RIP version 1 on your router? A. Router RIP

network 172.16.1.0network 10.1.0.1

B. Router RIP network 172.16.0.0network 10.0.0.0

C. Router RIP network 172.16.1.0 172.16.1.1network 10.1.0.0 10.1.1.1

D. Router RIP network 172.16.1.0 265.255.255.0Network 10.1.0.0 255.255.0.0 

Answer B 

QuestionYou have been hired as to troubleshoot the company’s network. You issue the debug ip rip command to troubleshoot the rip network. You notice your Ethernet interface 10.1.0.0 shuts down.  Which update message is seen in your routers debug ip rip output regarding that network? A. Subnet 10.1.0.0, metric 0 B. Subnet 10.1.0.0, metric 1 C. Subnet 10.1.0.0, metric 15 D. Subnet 10.1.0.0, metric 16

Answer D

QuestionYou are using RIP as your routing protocol. Your WAN service provider asks you to use the passive-interface command for the serial interface that is attached to the service provider. What does this command accomplish?

A. It puts the interface in shutdown.B. It tells a router to send routing updates out the interface but not to listen to any routing updates.C. It allows an interface to remain up despite the fact that the service provider does not provide keepalives.D. It tells a router to receive routing updates on an interface but not to send updates via that interface.

Answer D

The passive-interface command is used to control the advertisement of routing information. The command enables the suppression of routing updates over some interfaces while allowing updates to be exchanged normally over other interfaces. A is incorrect, as the actual command to turn off the interface is shutdown. B is incorrect, as this answer is the opposite of what the command does. C is incorrect, as keepalives keep up an Ethernet interface but do nothing for a serial interface.

QuestionYou are suggesting that your company uses IP RIP as its routing protocol. Your boss would like you to list some facts about IP RIP before he approves your request. Which of the following statements about IP RIP are true? (Choose two.)

A. It limits hop counts to 31. B. It is a link-state routing protocol. C. It uses autonomous system numbers. D. It is capable of load sharing over multiple paths. E. It uses bandwidth as the metric for path selection. F. It broadcasts updates every 30 seconds by defaults Answer D, F

ExplanationKey characteristics of RIP,it is a distance vector protocolhop count is used as the metric for path selectionmaximum allowable hop count is 15broadcast routing updates every 30 secondsRIP can be load balanced over as many as 6 equal cost pathsRIP 1 requires a major classful network number to advertise RIP 2 use VLSMs.

Incorrect answersA. RIP's maximum allowable hop count is 15. B. RIP is a distance vector protocol. C. It uses network numbers/VLSMs. E. Hop count is used as the metric for path selection.

QuestionYour company has decided to use RIP version 1 as the routing on a Cisco router. What is the command to enable rip as the routing protocol on the company’s router?

A. SET RIPB. SET ROUTER RIPC. RIPD. ROUTER RIP

Answer D

Explanation

The key characteristics of RIP include: it is a distance vector protocol, hop count is the metric used for path selection, it maximum allowable hop count is 15, it broadcasts it entire routing table every 30 seconds by default and it can be load balanced as many as six equal cost paths (4 paths are the default). To configure RIP not only does the router rip command need to be inputted but also it must be followed by the network command. The network command must be issued for each directly connected network.

QuestionYour company has decided to use IP RIP version 1 as the routing protocol. Which of the following are the commands you can use to configure IP RIP version 1 on your router?

A. Router RIPnetwork 172.16.1.0 network 10.1.0.1

B. Router RIP network 172.16.0.0 network 10.0.0.0

C. Router RIP network 172.16.1.0 172.16.1.1 network 10.1.0.0 10.1.1.1

D. Router RIP network 172.16.1.0 265.255.255.0 Network 10.1.0.0 255.255.0.0

Answer B

ExplanationTo enable RIP version 1 not only does the router rip command need to be used but also it must be followed by the network command. The network command must be issued for each directly connected network. The network command must be followed by a valid network address. Incorrect Answers:

A. Is this series of commands the network 10.1.0.1 is not a valid command.

C. If 4 networks are directly connected they must have their own network command. D. There is no need to include a subnet mask with a network command.

QuestionYou are configuring the Ike router on the network shown in the figure below. You would like to use the RIP routing protocol to propagate all the networks to the three routers shown. What configuration would you apply to Ike to have it participate in this objective?

A. Ike(config)#router rip Ike(config-router)#network 172.16.0.0 Ike(config-router)#network 192.168.45.0

B. Ike(config)#router rip Ike(config-router)#network 172.16.30.0 Ike(config-router)#network 192.168.35.0 Ike(config-router)#network 192.168.45.0 Ike(config-router)#network 192.168.55.0

C. Ike(config)#router rip Ike(config-router)#network 172.16.0.0 Ike(config-router)#network 192.168.35.0 Ike(config-router)#network 192.168.45.0 Ike(config-router)#network 192.168.55.0

D. Ike(config)#router rip Ike(config-router)#network 172.16.0.0 Ike(config-router)#network 192.168.0.0

Answer A

RIP is considered a classful protocol. From a configuration standpoint, this means that networks must be entered into the configuration using their default classes (Class A, B, or C). Because 172.16.0.0 is a class B network, it must be entered as if it had a class B subnet mask rather than the subnet mask shown in the figure. In addition, you enter directly connected interfaces only into a routing process. This concept applies to any routing protocol. In the case of Ike, it is connected only to the 172.16.0.0 and 192.168.45.0 networks.

B and C are incorrect because they enter all the networks rather than the networks that are directly connected to Ike. D is incorrect because it enters the 192.168.0.0 network in a class B style when this is a class C address.

QuestionYou need to install RIP on your router. Which command enables directly connected network 131.107.10.0 to be used by RIP? A. Router(Config)# rip 131.107.10.0

B. Router(Config-router)# rip 131.107.10.0 C. Router(Config-router)# network 131.107.10.0 D. Router(Config-router)# network 131.107.0.0 Answer D

ExplanationThe network command allows the routing process to identify the interfaces will participate in the sending and receiving of messages.

Incorrect AnswersA and B. These are not valid commands. In addition, A is in the wrong mode.C. This is the wrong network number. The 131.107.10.0 is a Class B subnet, using a default mask of 255.255.0.0.

Question

Routers B and C are configured for RIPv2 and have complete connectivity. Router A is added to the network. What is the most appropriate Router A configuration for full connectivity?

A. RouterA(config)# router rip RouterA(config)# network 10.0.0.0 RouterA(config)# network 172.16.0.0 RouterA(config)# network 192.168.1.0

B. RouterA(config)# router rip RouterA(config)# network 10.0.0.0

C. RouterA(config)# router rip RouterA(config)# network 10.0.0.0 RouterA(config)# network 172.16.0.0

D. RouterA(config)# router rip RouterA(config)# network 10.0.0.0 RouterA(config)# network 192.168.1.0

Answer C RouterA(config)# router rip RouterA(config)# network 10.0.0.0 RouterA(config)# network 172.16.0.0

Explanation: When configuring RIP you configure only the directly connected networks that are to be advertised via the RIP routing process are to be configured.

Incorrect Answers

A. This choice implies that when configuring rip on a router every possible network in the entire system should be configured. This is not the case. B. Router 1 requires the 172.16.0.0 network to be configured, not the 192.168.1.0 network. D. If the 172.16.0.0 network is omitted, then the other routers in the network will not be able to reach the LAN users of RouterA via RIP.

QuestionThe Ethernet 0 interface of a router was configured with address 10.64.0.1 255.224.0.0 while the Ethernet 1 interface was configured with address 10.96.0.1/11. Which commands could be used to configure RIP version 1 on this router to advertise both networks to neighboring routers? (Choose two.)

A. Router(config)# router rip Router(config-router)# network 10.0.0.0 255.224.0.0

B. Router(config)# router rip Router(config-router)# network 10.0.0.0

C. Router(config)# router rip Router(config-router)# network 10.64.0.0 Router(config-router)# network 10.96.0.0

D. Router(config)# router rip Router(config-router)# network 10.64.0.1 255.224.0.0 Router(config-router)# network 10.96.0.1 255.224.0.0

Answer B, C

Explanation: Both options B and C correctly include both of the networks in the routing process, making them correct. With RIP, the subnet mask is not specified as the networks involved are assumed to be classful.

Incorrect AnswersA, D. Both of these options incorrectly show a subnet mask used in the network commands under the routing process. This is not an option with RIP.

Question

In this network, you must configure router CK1 to provide connectivity to router CK2. The entire network must utilize the 192.1.1.0/24 network. If RIP is being used as the routing protocol, which 3 sets of commands will need to be completed on CK1? (Choose 3).

A. CK1(config)# interface ethernet 0 CK1(config-if)# ip address 192.1.1.129 255.255.255.192 CK1(config-if)# no shutdown

B. CK1(config)# interface ethernet 0

CK1(config-if)# ip address 192.1.1.97 255.255.255.192 CK1(config-if)# no shutdown

C. CK1(config)# interface serial 0 CK1(config-if)# ip address 192.1.1.4 255.255.255.252 CK1(config-if)# clock rate 56000

D. CK1(config)# interface serial 0 CK1(config-if)# ip address 192.1.1.6 255.255.255.252 CK1(config-if)# no shutdown

E. CK1(config)# router rip CK1(config-router)# network 192.1.1.4 CK1(config-router)# network 192.1.1.128

F. CK1(config)# router rip CK1(config-router)# version 2 CK1(config-router)# network 192.1.1.0

Answer A, D, F

ExplanationA is correct, a valid host is configured on E0 interface of the router 192.1.1.129/26. D is correct because each WAN link uses the /30 or 255.255.255.252 mask revealing 2 valid host addresses. Serial 0 is configured with the address 192.1.1.6/30, which comes from the subnet 192.1.1.4/30. Valid hosts in this subnet are 192.1.1.5/30 and 192.1.1.6/30 F is correct because we RIP version 2 will be required in this case as VLSM information needs to be carried throughout the network, and VLSM is not supported on RIP version 1.

Incorrect AnswersB. The IP address in use here will conflict with the LAN network configured on CK2. 192.1.1.65/26, 11000000 = 192, bs = 64 0, 64, 128, 192

65 is in the 64 subnet so CK2 hosts 65 – 127

C. the 192.168.1.4/30 address is a network address, not a host address.

192.1.1.5/30, 11111100 = 252bs = 4 subnets 0, 4, 8

QuestionWhich command or set of commands will stop the RIP routing process? A. RouterB(config)# router rip RouterB(config-router)# shutdown

B. RouterB(config)# router rip

RouterB(config-router)# network no 192.168.2.0

C. RouterB(config)# no router rip

D. RouterB(config)# router no rip

Answer C

RouterB(config)# no router rip

QuestionWhen does a distance vector routing protocol set a hold-down timer on a route? A. when the metric value of the route decreases B. when the route is marked as inaccessible C. when the metric value for the route improves D. when a regular update is received from a neighboring router

Answer B

when the route is marked as inaccessible

QuestionWhich of the following functions are performed by a router as routing information travels through the network? (Choose two.) A. advertise supported applications B. identify new destinations C. calculate packet speed D. verify network scalability E. identify invalid networks

Answer B, E

identify new destinations and identify invalid networks

QuestionWhat do distance vector algorithms require each router in the network to send? A. a partial routing table to each router in the LAN B. a partial routing table to each router in the WAN C. the entire routing table to each neighboring router D. the entire routing table to each router in the autonomous system

Answer C

the entire routing table to each neighboring router

Question

The administrator of the network depicted in the graphic would like to decrease the network's convergence time. How can this be accomplished? A. disable split horizon on the routers B. increase the update interval on the routers C. change the RIP holddown timer to 96 seconds D. change the RIP holddown timer to 226 seconds

Answer C

change the RIP holddown timer to 96s

ExplanationHolddown timer: This sets the amount of time during which routing information is suppressed. Routes will enter into the holddown state when an update packet is received that indicated the route is reachable. This continues either until an update packet is received with a better metric or until the holddown timer expires for RIP the default is 180s.

QuestionWhich statements describe load balancing when RIP is configured as the routing protocol? (Choose two.) A. A router is allowed to take advantage of multiple best paths to a given destination. B. RIP uses the round robin approach in load balancing. C. RIP load balancing selects a single path to forward all data to the destination even though equal parallel paths exist. D. RIP load balancing is based on bandwidth first and then the hop count. E. Only one path to a destination can be statically assigned or dynamically calculated.

Answer A, B

Question

Which of the following would be the correct command sequence to enable RIP on Router B for all connected networks? A. RouterB# router ripRouterB(router)# network 210.36.7.0RouterB(router)# network 220.17.29.0RouterB(router)# network 211.168.74.0

B. RouterB(config)# router ripRouterB(config-router)# network 198.16.4.0RouterB(config-router)# network 211.168.74.0RouterB(config-router)# network 199.84.32.0

C. RouterB(config)# configure router ripRouterB(config-router)# network 210.36.7.0RouterB(config-router)# network 199.84.32.0RouterB(config-router)# network 211.168.74.0

D. RouterB(config)# router ripRouterB(config-router)# network 198.16.4.0RouterB(config-router)# network 210.36.7.0RouterB(config-router)# network 211.168.74.0

E. RouterB(config)# router ripRouterB(config-router)# network 198.16.4.0RouterB(config-router)# network 210.36.7.0RouterB(config-router)# network 220.17.29.0

Answer E

RouterB(config)# router ripRouterB(config-router)# network 198.16.4.0RouterB(config-router)# network 210.36.7.0RouterB(config-router)# network 220.17.29.0

QuestionRouterTK#show ip routeCodes: C-connected,s-static,I-IGRP,R-RIP,M-Mobile,B-BGP..........D-EIGRP,EIGRP external, O-OSPF,IA-OSPF inter area,..........EI-OSPF external type 1,E2-OSPF external type 2, E-EGP,..........i-IS-IS,L1-IS-IS level-1,L2-IS-IS level-2,*-candidate default,..........U-per-user static route Gateway of last resort is not set R 192.168.8.0/24 [120/1] via 192.168.2.2, 00:00:10, Serial0 C 192.168.9.0/24 is directly connected, Serial 1 R 192.168.10.0/24 [120/7] via 192.168.9.1, 00:00:02, Serial1 R 192.168.11.0/24 [120/7] via 192.168.9.1, 00:00:03, Serial1 C 192.168.1.0/24 is directly connected, Ethernet0 C 192.168.2.0/24 is directly connected, Serial0 R 192.168.3.0/24 [120/1] via 192.168.2.2, 00:00:10, Serial0 R 192.168.4.0/24 [120/15] via 192.168.2.2, 00:00:10, Serial0 R 192.168.5.0/24 [120/15] via 192.168.2.2, 00:00:10, Serial0 R 192.168.6.0/24 [120/15] via 192.168.2.2, 00:00:10, Serial0 R 192.168.7.0/24 [120/1] via 192.168.2.2, 00:00:10, Serial0

Based on the output of the show ip route command which route will not be entered into a neighbour RIP router?

A. R 192.168.3.0/24 [120/1] via 192.168.2.2, 00:00:10, Serial0 B. R 192.168.11.0/24 [120/7] via 192.168.9.1, 00:00:03, Serial1 C. C 192.168.1.0/24 is directly connected, Ethernet0

D. R 192.168.5.0/24 [120/15] via 192.168.2.2, 00:00:10, Serial0

Answer D

ExplanationThis route has the worst metric of those listed and as such will not be shared with the neighbour. RIP has the maximum hop count of 15. This route already has a hop count of 15 and adding one would make it unreachable.

Incorrect AnswersA. This has the best metric thus it will be shared. B. This route has a better metric therefore it will be shared. C. This is a directly connected network thus it will be shared.

QuestionWhich of the following commands are required to turn on RIP routing on your network? (Choose two.)

A. R4(config)#router rip

B. R4(config)#router rip 100

C. R4(config-router)#network 192.168.0.0

D. R4(config-router)#network all

Answers A and C

You must turn on the routing protocol with the router rip command from Global Configuration mode. You must then specify interfaces to advertise; the network command accomplishes this. B is incorrect, as you do not need to specify an autonomous system for RIP, as you would IGRP. D is incorrect, as it is not a valid network command. QuestionA router learns two routes to a remote network, one route via OSPF and one route via RIPv2. The network administrator wants the router to install the route learned via RIPv2 into its routing table. What should the network administrator configure to ensure that the router will use the route learned via RIPv2?

A. Nothing. The router will automatically use routes learned via RIP over routes learned via OSPF.

B. The network administrator should configure the routers along the OSPF path with lower priority numbers. C. The network administrator should configure the router interface on the OSPF path to be a passive interface. D. The network administrator should configure an administrative distance for RIP that is lower than the administrative distance of OSPF. E. If two paths exist to a remote network, the only way to force the router to prefer one path over the other is to configure the preferred path as a static route.

Answer D

Explanation: When multiple routing protocols are configured for the same networks, the router will use the path with the lowest Administrative Distance (AD). By default, OSPF has and AD of 110 and RIP has an AD of 120. In order to ensure that the router prefers the route learned via RIP over OSPF, the AD of the RIP route must be reduced to a value less than 120.

QuestionYou are running RIP version 2 in your enterprise network. You are interested in creating a summary route and advertising this route out the Serial 2 interface of one of your routers. The summary address is 10.10.0.0 255.255.0.0. What is the correct command to use to configure this summary address?

A. Manual address summarization is not possible with RIP.

B. Router(config-router)#ip summary-address 10.10.0.0 255.255.0.0

C. Router(config-if)#ip summary-address 10.10.0.0 255.255.0.0

D. Router(config-if)#ip summary-address rip 10.10.0.0 255.255.0.0

Answer D

Router(config-if)#ip summary-address rip 10.10.0.0 255.255.0.0

QuestionWhich IP address would be appropriate for the S0/0 interface of the LCAG router shown in the diagram below?

A. 172.16.0.25 /27 B. 192.168.17.125 /27

C. 10.16.7.13 /27 D. 192.168.17.17 /27 E. 10.16.7.129 /27 F. 172.18.7.49 /27

Answer D

Explanation: Since RIPv1 is being used, we need to ensure that the subnet mask is /27 like the other internal networks as RIPv1 does not support VLSM. We will also need to use something in the 192.168.17.X network since all the other networks are 192.168.17.X. This leaves only choices B and D viable at this point.

Since we can see from this that the 192.168.17.125 IP address lies within the 192.168.17.96/27 network, we can not use this network as it is already being used by the network attached to Fa 0/1 of the MAFLD router. This leaves choice D as the only correct option. This can be verified by the fact that the 192.168.17.0-31 IP addresses are not being used anywhere else within the enterprise.

Question

Three networks have 50 hosts each and one network has 10 hosts. The multi-vendor routers are connected by serial links that use separate subnets. One Class C address is to be used for all networks and serial links and they do not wish to replace any of their existing routers Which is the most appropriate protocol?

A. TCP/IPB. RIP v1C. RIP v2D. IGRPE. EIGRPG. All are acceptable

Answer C

One class C address range for all networks therefore VLSM is needed rules out RIP v1 and IGRP also multiple vendors used so only OSPF or RIPv2 viable choices OSPF not an option.D. E are Cisco proprietary.

RIP SIM

Description Acme Inc. is a multinational company, whose headquarters are located in Istanbul. The company demands end-to-end connectivity between headquarters and the two branch offices, Berlin and Paris.

Tasks on Istanbul1. Erase initial router configuration2. Configure Hostname; enable, vty and console passwords. All passwords will be set to ‘cisco’3. a. Configure interfaces by assigning them the appropriate IP Addresses given in the topology b. Check whether the serial interfaces are DCE or DTE. Set clock rate if required.4. a. Configure RIP to provide end-to-end connectivity b. Check end-to-end connectivity5. Save your configurations into router’s NVRAM

Solution for Step 1

Router#Router#erase startErasing the nvram filesystem will remove all files! Continue? [confirm][OK]Erase of nvram: completeRouter#reload

System configuration has been modified. Save? [yes/no]: nProceed with reload? [confirm]

01:12:03: %SYS-5-RELOAD: Reload requested

System Bootstrap, Version 5.2(8a), RELEASE SOFTWARECopyright (c) 1986-1995 by cisco Systems

Solution for Step 2

Router>enableRouter#conf tEnter configuration commands, one per line. End with CNTL/Z.Router(config)#hostname ISTANBULISTANBUL(config)#enable secret ciscoISTANBUL(config)#line vty 0 4ISTANBUL(config-line)#password ciscoISTANBUL(config-line)#line console 0ISTANBUL(config-line)#loginISTANBUL(config-line)#password CiscoISTANBUL(config-line)#end

Solution for Step 3

ISTANBUL(config)#int serial 0ISTANBUL(config-if)#ip address 192.168.1.1 255.255.255.0ISTANBUL(config-if)#no shut00:32:24: %LINK-3-UPDOWN: Interface Serial0, changed state to downISTANBUL(config-if)#int serial 1ISTANBUL(config-if)#ip address 176.16.1.1 255.255.255.0ISTANBUL(config-if)#no shut

ISTANBUL(config-if)#int ethernet 0ISTANBUL(config-if)#ip address 202.1.1.1 255.255.255.0ISTANBUL(config-if)#no shut

ISTANBUL#sh controllers serial 0HD unit 0, idb = 0x9F514, driver structure at 0xA31C0buffer size 1524 HD unit 0, V.35 DCE cablecpb = 0x21, eda = 0x4940, cda = 0x4800RX ring with 16 entries at 0x21480000 bd_ptr=0x4800 pak=0x106648 ds=0x21EC68 status=80 pak_size=0!Output Omitted for simplicity

ISTANBUL#conf tEnter configuration commands, one per line. End with CNTL/Z.ISTANBUL(config)#int serial 0ISTANBUL(config-if)#clock rate 64000ISTANBUL(config-if)#end%SYS-5-CONFIG_I: Configured from console by consoleISTANBUL#sh controllers s 0 HD unit 0, idb = 0x9F514, driver structure at 0xA31C0buffer size 1524 HD unit 0, V.35 DCE cable, clockrate 64000cpb = 0x21, eda = 0x4940, cda = 0x4800RX ring with 16 entries at 0x21480000 bd_ptr=0x4800 pak=0x106648 ds=0x21EC68 status=80 pak_size=0!Output Omitted for simplicity

Note Do not set clock rate on DTE interfaces.

Solution for Step 4

ISTANBUL(config)#router ripISTANBUL(config-router)#network 192.168.1.0ISTANBUL(config-router)#network 202.1.1.0ISTANBUL(config-router)#network 172.16.0.0 !!!

!!! Important Note for the CCNA Exam It’s a common mistake to write this command as

ISTANBUL(config-router)#network 172.16.1.0

Your router will accept this command and indicate no error message. Furthermore, you won’t encounter any problems in connectivity. However look at the output of show run

!router rip network 172.16.0.0 network 192.168.1.0 network 202.1.1.0!

172.16 is a B class IP address and the network command is classless, so the last two octets will be neglected.

Although this may cause not much trouble in the real world, it will definitely reduce your score in the CCNA exam.

Solution for Step 5

BERLIN#copy running-config startup-configDestination filename [startup-config]? Building configuration...[OK]