ccna routing labs

7/27/2019 CCNA Routing Labs

http://slidepdf.com/reader/full/ccna-routing-labs 1/20

CCNA Routing Labs

Three Router RIP Lab

The purpose of this lab is to explore the functionality of the RIP routing protocol. The main goal

is to allow PC1 to reach PC2 and vice versa.

Hardware Required for Lab

A Cisco router with two Fa0/0 interfaces and one serial port.

A Cisco router with two Fa0/0 interfaces and one serial port.

A Cisco router with two Fa0/0 interfaces.Two straight through Cat 5 cable

Two crossover Cat 5 cables

One smart serial cable or two DCE/DTE serial cables depending on router.One Console Cable

Two PCs to connect to the routers

Commands Used in Lab

enable - Used to move from unprivileged mode to privileged mode.

show ip interface brief - Displays a brief summary of the interfaces on the router, what IPs they

have configured, and their status.

Initial Configs

R1

host R1line con 0

logging synch

exit

int fa0/0

ip add 192.168.12.1 255.255.255.0

no shut

int fa2/0

ip add 192.168.11.1 255.255.255.0

no shut

http://premium.certificationkits.com/ccna-labs/28-ccna-routing-labs/284-three-router-rip-lab.html





int s1/0

ip add 192.168.131.1 255.255.255.0

clock rate 64000

no shut

exit

int loopback 1

ip add 1.1.1.1 255.255.255.255

R2

host R2

line con 0

logging synch

exit

int fa0/0

ip add 192.168.12.2 255.255.255.0

no shut

int fa1/0

ip add 192.168.23.2 255.255.255.0

no shut

exit

int loopback 1ip add 2.2.2.2 255.255.255.255

R3

host R3

line con 0

logging synch

exit

int fa0/0

ip add 192.168.23.3 255.255.255.0

no shut

int fa2/0

ip add 192.168.33.1 255.255.255.0

no shut

int s1/0

ip add 192.168.131.3 255.255.255.0

clock rate 64000

no shut

exit

int loopback 1

ip add 3.3.3.3 255.255.255.255

PC1



PC2



Note: Even though the nature of serial links require a clock rate to be set

on the DCE, you can safely add the clock rate to each side of thelink. The router with the DTE end of the link will simply ignore the command.

RIP is one of the oldest and simplest routing protocols that is still in use and will be around for some time to come.

Enabling RIP on the router is done with the router rip command

Once RIP is enabled it is necessary to use network statements to tell the router which interfaces

are going to send and receive RIP updates.

The network statement uses the following syntax:

network <classful network>

Most people have trouble understanding the purpose of the network statements when they are

first learning routing protocols because they commonly assume that the command is used toadvertise networks into RIP. This is not correct, when you enter the network command under

RIP the router will check what interfaces match the classful network and adds the interface to

the routing process.

As a refresher the classful networks are:



Class Leading bits Start EndCIDR suffix

Defaultsubnet mask

Class A 0 0.0.0.0 127.255.255.255 /8 255.0.0.0

Class B 10 128.0.0.0 191.255.255.255 /16 255.255.0.0

Class C 110 192.0.0.0 223.255.255.255 /24 255.255.255.0

Class D (multicast) 1110 224.0.0.0 239.255.255.255 /4 not definedClass E (reserved) 1111 240.0.0.0 255.255.255.255 /4 not defined

Lets configure RIP between R1 and R2 for all networks

R1(config)#router rip

R1(config-router)#network 192.168.11.0



R2(config)#router rip R2(config-router)#network 192.168.12.0



Lets explore the RIP configure on R1 a bit more in depth, checking the show run config we can

see that even though we entered the loopback network as 1.1.1.1 the router scaled it back to itsclassful boundary.

R1#show run | sec router

router rip

network 1.0.0.0

network 192.168.11.0

network 192.168.12.0

A quick way to check various information about RIP including what interfaces RIP is running on

is: show ip protocols

R1#show ip protocols

Routing Protocol is "rip"

Outgoing update filter list for all interfaces is not setIncoming update filter list for all interfaces is not set

Sending updates every 30 seconds, next due in 26 seconds

Invalid after 180 seconds, hold down 180, flushed after 240

Redistributing: rip

Default version control: send version 1, receive any version

Interface Send Recv Triggered RIP Key-chain

FastEthernet0/0 1 1 2

FastEthernet2/0 1 1 2

Loopback1 1 1 2

Automatic network summarization is in effect

Maximum path: 4

Routing for Networks:

1.0.0.0192.168.11.0

192.168.12.0

Routing Information Sources:

Gateway Distance Last Update

192.168.12.2 120 00:00:00

Distance: (default is 120)

Lets take a moment to go over some of the output shown from show ip protocols



Sending updates every 30 seconds, next due in 26 secondsInvalid after 180 seconds, hold down 180, flushed after240

These are the current timers that R

Interface Send Recv Triggered RIP Key-chainFastEthernet0/0 1 1 2FastEthernet2/0 1 1 2Loopback1 1 1 2

This shows what interfaces RIP is

RIPv2 for all other labs.

Automatic network summarization is in effect This shows that RIP is summarizinRouting for Networks:1.0.0.0192.168.11.0192.168.12.0

This is a quick summary of what n

Routing Information Sources:Gateway Distance Last Update192.168.12.2 120 00:00:00

This section is used to quickly see

Distance: (default is 120) This shows the administrative dist

Now that we have an idea about how RIP is configured, lets check the routing table to see whats

there.

R1#show ip route

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2

i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

ia - IS-IS inter area, * - candidate default, U - per-user static route

o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

C 192.168.12.0/24 is directly connected, FastEthernet0/0

1.0.0.0/32 is subnetted, 1 subnets

C 1.1.1.1 is directly connected, Loopback1C 192.168.131.0/24 is directly connected, Serial1/0

R 2.0.0.0/8 [120/1] via 192.168.12.2, 00:00:04, FastEthernet0/0



You should already be somewhat familar with the basics of the routing table from earlier labs,

whats new is now we are now seeing seeing RIP routes which are denoted with an "R"

Notice that the 192.168.12.0/24 network is not seen as a RIP route because its directly connectedand the router will always believe its directly connected routes over anything.

You can also filter the routing table by protocol to help you focus on exactly what your

interested in

R1# show ip route ?

Hostname or A.B.C.D Network to display information about or hostname

bgp Border Gateway Protocol (BGP)

connected Connected

dhcp Show routes added by DHCP Server or Relay

eigrp Enhanced Interior Gateway Routing Protocol (EIGRP)

isis ISO IS-IS

list IP Access list

mobile Mobile routes



odr On Demand stub Routes

ospf Open Shortest Path First (OSPF)

profile IP routing table profile

rip Routing Information Protocol (RIP)

static Static routes

summary Summary of all routes

supernets-only Show supernet entries only

track-table Tracked static table

update-queue Queue of RIB updates

vrf Display routes from a VPN Routing/Forwarding instance

| Output modifiers

<cr>

R1# show ip route rip



Lets take a minute to show explain the output of the routing table

R Denotes a RIP route2.0.0.0/8 This is the learned route and subnet mask 120 This is the administrative distance for RIP, by default it is 1201 This is how many hops away the route is, in RIP a hop is each routevia 192.168.12.2 This is the next hop neighbor that the route was learned from00:00:10 This is the age of the route since the last update, when everything isFastEthernet0/0 Lastly this is the interface the route was learned on.

Notice that even though R2's loopback is 2.2.2.2/32 RIP has striped the network back to its

classful boundary 2.0.0.0/8 This is because RIPv1 doesn't send any subnet mask information

with its routing updatesso the receiving router has no choice but to assume a classful boundary. This behavior can been

seen in the following debug.

R1#debug ip rip

RIP protocol debugging is on

R1#

*Mar 1 00:43:32.991: RIP: received v1 update from 192.168.12.2 on FastEth

*Mar 1 00:43:32.995: 2.0.0.0 in 1 hops

*Mar 1 00:43:32.999: 192.168.23.0 in 1 hops

R1#

*Mar 1 00:43:35.915: RIP: sending v1 update to 255.255.255.255 via FastEt

*Mar 1 00:43:35.919: RIP: build update entries

*Mar 1 00:43:35.919: network 1.0.0.0 metric 1

*Mar 1 00:43:35.923: network 192.168.131.0 metric 1

R1#un all

All possible debugging has been turned off

One of the many pitfalls of RIPv1 is that it simply broadcasts its update to everyone (the255.255.255.255 address) This means that every host on the network will receive the RIP

updates whether they want them or not!!!

Below is a packet capture of traffic going to PC1, even though the PC isn't runnng RIP it is stillreceiving all the RIP packets which can be both a waste of bandwidth and a security concern.



Note: You can ping multicast or broadcast addresses from a router to quicklysee what hosts will receive certain kinds of packets

R1# ping 255.255.255.255

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 255.255.255.255, timeout is 2 seconds:

Reply to request 0 from 192.168.131.3, 20 ms

Reply to request 0 from 192.168.12.2, 36 ms

Since RIPv1 isn't on the CCNA (or any Cisco exam) anymore we won't spend anymore time onit. Before we switch to RIPv2 we'll first add the remaining interfaces into RIP


R3(config-router)#network 192.168.33.0R3(config-router)#network 192.168.23.0



To use RIPv2 you simply need to type: version 2 under the RIP configuration.


R1(config-router)#version 2




R2(config-router)#ver 2


R3(config-router)#ver 2

We can confirm RIPv2 is running in a couple ways, lets start by looking at the show ip

protocols output. Notice that the Send/Receive verison is now just 2

R1# show ip protocolsRouting Protocol is "rip"

Outgoing update filter list for all interfaces is not set

Incoming update filter list for all interfaces is not set

Sending updates every 30 seconds, next due in 22 seconds

Invalid after 180 seconds, hold down 180, flushed after 240

Redistributing: rip

Default version control: send version 2, receive version 2

Interface Send Recv Triggered RIP Key-chainFastEthernet0/0 2 2Serial1/0 2 2FastEthernet2/0 2 2Loopback1 2 2

Automatic network summarization is in effect

Maximum path: 4

Routing for Networks:

1.0.0.0

192.168.11.0

192.168.12.0

192.168.131.0

Routing Information Sources:

Gateway Distance Last Update

192.168.131.3 120 00:00:14

192.168.12.2 120 00:00:20

Distance: (default is 120)

Another way is check the debug output with: debug ip rip which is RIPs only really useful

debug option.

R1#debug ip rip


R1#

*Mar 1 01:24:13.519: RIP: received v2 update from 192.168.131.3 on Serial

*Mar 1 01:24:13.523: 3.0.0.0/8 via 0.0.0.0 in 1 hops

*Mar 1 01:24:13.527: 192.168.23.0/24 via 0.0.0.0 in 1 hops

*Mar 1 01:24:13.531: 192.168.33.0/24 via 0.0.0.0 in 1 hops

R1#


*Mar 1 01:24:16.315: 2.0.0.0/8 via 0.0.0.0 in 1 hops

*Mar 1 01:24:16.319: 3.0.0.0/8 via 0.0.0.0 in 1 hops

*Mar 1 01:24:16.323: 192.168.23.0/24 via 0.0.0.0 in 1 hopsR1#

*Mar 1 01:24:21.167: RIP: sending v2 update to 224.0.0.9 via FastEthernet


*Mar 1 01:24:21.171: 1.0.0.0/8 via 0.0.0.0, metric 1, tag 0









Theres a few things to notice about the debug output, for one it clearly says its sending v2

updates but now it is sending them to the RIP multicast address: 224.0.0.9 instead of

broadcasting to everyone.Also notice that subnet masks being sent with the updates now, though you may find it odd that

the loopbacks are still being advertised by their classful boundary. This is because RIPv2 will by

default continueto automatically summarize routes - This behavior can be turned off with: no auto-

summary this command will need to be entered on all routers participanting in RIP.


R1(config-router)#no auto-summary





Checking the debug again we can see that the proper routes are being advertised.

R2#debug ip rip


R2#

*Mar 1 01:35:53.871: RIP: sending v2 update to 224.0.0.9 via FastEthernet



*Mar 1 01:35:53.879: 1.1.1.1/32 via 0.0.0.0, metric 2, tag 0*Mar 1 01:35:53.879: 2.2.2.2/32 via 0.0.0.0, metric 1, tag 0



R2#


*Mar 1 01:35:57.859: 1.1.1.1/32 via 0.0.0.0 in 1 hops

*Mar 1 01:35:57.863: 3.0.0.0/8 via 0.0.0.0 in 2 hops

*Mar 1 01:35:57.863: 3.3.3.3/32 via 0.0.0.0 in 2 hops

*Mar 1 01:35:57.867: 192.168.11.0/24 via 0.0.0.0 in 1 hops

*Mar 1 01:35:57.871: 192.168.131.0/24 via 0.0.0.0 in 1 hops

*Mar 1 01:35:57.875: 192.168.33.0/24 via 0.0.0.0 in 2 hops

If we try to ping from PC1 to PC2 we can see it is successful because R1 knows about the192.168.33.0/24 network

.



Lets see how this looks in the routing table, we can see that RIP is choosing to use the serial link

to get to the 192.168.33.0/24 network even though has the choice between two routers with100mbs connections or one with two

64kbs links which clearly isn't the quickest route.

R1#sh ip route rip


R 2.2.2.2 [120/1] via 192.168.12.2, 00:00:03, FastEthernet0/0


R 3.3.3.3 [120/1] via 192.168.131.3, 00:00:11, Serial1/0

R 192.168.23.0/24 [120/1] via 192.168.131.3, 00:00:11, Serial1/0

[120/1] via 192.168.12.2, 00:00:03,

R 192.168.33.0/24 [120/1] via 192.168.131.3, 00:00:11, Serial1/0

This is because RIP only takes hop count into consideration, R1 - R3's link is one hop which

beats R1 -> R2 -> R3 this can be seen in the following debug


*Mar 1 02:00:07.975: 2.2.2.2/32 via 0.0.0.0 in 1 hops

*Mar 1 02:00:07.979: 3.3.3.3/32 via 0.0.0.0 in 2 hops

*Mar 1 02:00:07.979: 192.168.23.0/24 via 0.0.0.0 in 1 hops

*Mar 1 02:00:07.983: 192.168.33.0/24 via 0.0.0.0 in 2 hop

*Mar 1 02:00:03.043: RIP: received v2 update from 192.168.131.3 on Se

*Mar 1 02:00:03.047: 2.2.2.2/32 via 0.0.0.0 in 2 hops*Mar 1 02:00:03.051: 3.3.3.3/32 via 0.0.0.0 in 1 hops

*Mar 1 02:00:03.055: 192.168.23.0/24 via 0.0.0.0 in 1 hops

*Mar 1 02:00:03.055: 192.168.33.0/24 via 0.0.0.0 in 1 hops

We can test this out with the ping and traceroute commands

R1(config-if)#do ping 192.168.33.1





!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 8/25/60 ms

R1#traceroute 192.168.33.1


Tracing the route to 192.168.33.1

1 192.168.131.3 44 msec 36 msec *

When using the serial link pings take 60 ms to get across the link. Now lets disable the serial

link on R1 and try this again.

R1(config)#int s1/0

R1(config-if)#shut

R1(config-if)#exit

R1(config)#

*Mar 1 02:13:58.235: %LINK-5-CHANGED: Interface Serial1/0, changed state to

*Mar 1 02:13:59.235: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1

Pinging again from R1 we can see that it is using the ethernet links this time and and the pings

only take 24msR1#ping 192.168.33.1



!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 12/16/24 ms

R1#traceroute 192.168.33.1


Tracing the route to 192.168.33.1

1 192.168.12.2 40 msec 48 msec 24 msec

2 192.168.23.3 4 msec 40 msec *

RIP does provide a feature that can modify a routes metric called an Offset-List Offset-lists can be used to increase the hop count of a route but can't be used to decrease the hopcount. Its importent to keep track of how many hops a route will have when changing

the hop metric because RIP only allows any given route to have 15 hops this is help guard

against loops and in reality if your network has more then 15 hops you probably won't want touse RIP anyway.

The syntax for offset-lists are: offset-list <access-list> <in/out> <offset><interface>

R1(config-router)#offset-list ?

<0-99> Access list of networks to apply offset (0 selects all networ

<1300-1999> Access list of networks to apply offset (expanded range)

WORD Access-list name

R1(config-router)#offset-list 0 ?

in Perform offset on incoming updates

out Perform offset on outgoing updates

R1(config-router)#offset-list 0 in ?

<0-16> Offset

R1(config-router)#offset-list 0 in 5 ?

Async Async interface

BVI Bridge-Group Virtual Interface

CDMA-Ix CDMA Ix interface



CTunnel CTunnel interface

Dialer Dialer interface

FastEthernet FastEthernet IEEE 802.3

Lex Lex interface

Loopback Loopback interface

MFR Multilink Frame Relay bundle interface

Multilink Multilink-group interface

Null Null interface

Port-channel Ethernet Channel of interfaces

Serial Serial

Tunnel Tunnel interface

Vif PGM Multicast Host interface

Virtual-PPP Virtual PPP interface

Virtual-Template Virtual Template interface

Virtual-TokenRing Virtual TokenRing

<cr>

R1(config-router)#offset-list 0 in 5 fa1/0 ?

<cr>

Note: Anytime you see <cr> in the ? output this means you can press enter, any other

options past that point are optional

Here's a break down of the various command options.

access-list Access-list that defines what routes will be affected by the offset-list,access-list 0 Special meaning access-list that means all routes will be affected by oin This means the offset will be applied to matching inbound RIP routes.

out This means the offset will be applied to matching outbound RIP route

offset # This is how many hops to ADD to the route's hop count. If a route ha

interface(Optional) Further filter what routes are matched by what interface wi

be offset

After you go through the Access-list labs you'll understand the various list options but for now

we'll stick with access-list 0 for our examples.At the moment we have R1 using the serial link to get to the 192.168.33.0 network because it isonly one hop and is 2 hops when using the ethernet links.

R1(config)#do show ip route rip


R 192.168.33.0/24 [120/1] via 192.168.131.3, 00:00:22, Serial0/0

R1(config)#

*Mar 1 04:40:16.686: RIP: received v2 update from 192.168.131.3 on Serial0/0

*Mar 1 04:40:16.686: 192.168.23.0/24 via 0.0.0.0 in 1 hops

*Mar 1 04:40:16.686: 192.168.33.0/24 via 0.0.0.0 in 1 hops

*Mar 1 04:40:30.974: RIP: received v2 update from 192.168.12.2 on FastEthern

*Mar 1 04:40:30.978: 192.168.23.0/24 via 0.0.0.0 in 1 hops*Mar 1 04:40:30.982: 192.168.33.0/24 via 0.0.0.0 in 2 hops

Lets add a couple hops to all routes coming in from R1's S0/0 interface


R1(config-router)#offset-list 0 in 2 s0/0

After R1 receives the next update (every 30 seconds for RIP) it will change the serial route's

metric to 3 and the Fa1/0 route will be prefered.



R1(config)#do sh ip route rip



Checking on a debug we can see that both R3 routes over the serial link are now shown as 3

hops.R1#*Mar 1 04:47:40.014: RIP: received v2 update from 192.168.131.3 on Serial0/0

*Mar 1 04:47:40.018: 192.168.23.0/24 via 0.0.0.0 in 3 hops

*Mar 1 04:47:40.022: 192.168.33.0/24 via 0.0.0.0 in 3 hops

Lets adjust the offset-list to make the metric the same for the serial and the Fa1/0 links, since the

serial link is 1 hop and the Ethernet link is 2, we'll just add 1 to theserial link.R1(config)#router rip

R1(config-router)# offset-list 0 in 1 s0/0

Now when we check the routing table we can see that we now have two paths to get to the

192.168.33.0 network, RIP by default will load share between 6 equal cost paths.This provides redundence so if one of the paths have an issue, RIP will eventually detect the

issue and remove the path from the routing table.

R1#sh ip route rip


R 192.168.33.0/24 [120/2] via 192.168.131.3, 00:00:15, Serial0/0

[120/2] via 192.168.12.2, 00:00:00, FastEthernet1/0

I say eventually detect the issue because RIP is a very slow moving, lazy protocol. It updates

every 30 seconds

R1#sh ip route

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2

i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

ia - IS-IS inter area, * - candidate default, U - per-user static rout

o - ODR, P - periodic downloaded static route

Gateway of last resort is not set



C 192.168.131.0/24 is directly connected, Serial0/0

R 192.168.23.0/24 [120/1] via 192.168.12.2, 00:00:07, FastEtherne

R 192.168.33.0/24 [120/2] via 192.168.131.3, 00:00:07, Serial0/0


To test this I'm going to "accidentally" apply an access-list that blocks all traffic onto R1's Fa1/0interface.

R1(config)#access-list 5 deny any

R1(config)#int fa1/0

R1(config-if)#ip access-group 5 in

We can tel something is wrong because the 2 routes haven't seen an update in over a minute

when its supposed to update every 30 seconds.



R1#show ip route rip


R 192.168.33.0/24 [120/2] via 192.168.131.3, 00:00:15, Serial0/0


Routes are still present in the table at the 2 minute mark...

R1#show ip route ripR 192.168.23.0/24 [120/1] via 192.168.12.2, 00:02:01, FastEthernet1/0

R 192.168.33.0/24 [120/2] via 192.168.131.3, 00:00:09, Serial0/0


R1#show ip route rip

Almost 3 minutes....R1#show ip route rip


R 192.168.33.0/24 [120/2] via 192.168.131.3, 00:00:03, Serial0/0


Once the routes hit the 3 minute mark they go into the hold down timer and are listed as possiblydown.R1#show ip route rip

R 192.168.23.0/24 is possibly down, routing via 192.168.12.2, FastEthernet

R 192.168.33.0/24 [120/2] via 192.168.131.3, 00:00:06, Serial0/0

After 240 seconds the routes are fully flushed from the routing table.R1#show ip route rip

R 192.168.23.0/24 [120/2] via 192.168.131.3, 00:00:05, Serial0/0

R 192.168.33.0/24 [120/2] via 192.168.131.3, 00:00:05, Serial0/0

As you can see it takes a few minutes for RIP to correct a problem and possible another coupleminutes for all the routers to agree there is an issue and remove the route if you have a larger

RIP domain.Compared with Static routes where it will never detect the problem this is an improvement,however compared to other protocols that can detect changes in a matter of seconds it clearly

can't compete.

Below is a Pros & Cons summary of RIP.

Pros Cons

Simplest Routing Protocol Slow problem detection

Most devices support RIP.15 hop maximum and slow detect

deployments.

Supports VLSM in Version 2.

...keep reading

Three Router EIGRP Lab




http://premium.certificationkits.com/ccna-labs/28-ccna-routing-labs/285-three-router-eigrp-lab.html






The purpose of this lab is to explore the functionality of the EIGRP routing protocol. .. .keep

reading

Three Router OSPF Lab

The purpose of this lab is to explore the functionality of OSPF using a single area.This lab focuses many on the basics and concepts of OSPF to get you used to it. ...keep reading

Default Routing Lab

The purpose of this lab is to explore a common default routing scenario ...keep reading

Four Router Split Horizon RIP Lab





http://premium.certificationkits.com/ccna-labs/28-ccna-routing-labs/286-three-router-ospf-lab.html





http://premium.certificationkits.com/ccna-labs/28-ccna-routing-labs/287-default-routing-lab.html





http://premium.certificationkits.com/ccna-labs/28-ccna-routing-labs/288-four-router-split-horizon-rip-lab.html











The purpose of this lab is to explore the Split-horizon rule for RIP. ...keep reading

Four Router Split Horizon EIGRP Lab

The purpose of this lab explores the Split-horizon rule for EIGRP.

Hardware Required for Lab

3 Cisco routers with serial ports.1 Cisco router with at least 3 serial ports.

3 smart serial cables, or 6 DCE/DTE cables.




http://premium.certificationkits.com/ccna-labs/28-ccna-routing-labs/289-four-router-split-horizon-eigrp-lab.html






One Console Cable

Commands Used in Lab

no ip spli t-hor izon eigrp <AS> - Disables Split-horizon on an interface..

Inital Configs

FRAME

host FRAME

frame-relay switching

interface Serial0/1

encapsulation frame-relay

clock rate 64000

frame-relay intf-type dce

frame-relay route 102 interface Serial0/2 201


interface Serial0/2


clock rate 64000frame-relay intf-type dce


interface Serial0/3


clock rate 64000

frame-relay intf-type dce


R1

line console 0

logging synch

int s0/0

encapsulation frame-relayno frame inverse

no shut

int s0/0.123 multi

ip add 123.123.123.1 255.255.255.0

frame map ip 123.123.123.2 102 broadcast


host R1

R2

line console 0

logging synch

int s0/0


no frame inverseno shut

int s0/0.123 multi

ip add 123.123.123.2 255.255.255.0


host R2

R3

line console 0



logging synch

int s0/0


no frame inverse

no shut

int s0/0.123 multi

ip add 123.123.123.3 255.255.255.0


no shut

host R3

Distance routing protocols have a simple loop prevention rule called Split-horizon. The split-

horizon rule says that a routing protocol will not send out an update

on the same interface it received an update on. This is a particular problem on Frame-relay Huband Spoke networks because the hub will receive an update

from one spoke but due to split-horizon will not forward the update to the other spokes since its

the same interface.

First lets add a loopback interface on each router, we will use the 150.101.123.x/32 schemewhere X is the router number.

R1(config)#int lo0

R1(config-if)#ip add 150.101.123.1 255.255.255.255

R2(config)#int lo0

R2(config-if)#ip add 150.101.123.2 255.255.255.255

R3(config)#int lo0

R3(config-if)#ip add 150.101.123.3 255.255.255.255

Next lets enable EIGRP AS 123 on the frame network and add the loopbacks.R1(config)#router eigrp 123

R1(config-router)#no autoR1(config-router)#network 123.123.123.0 255.255.255.0

R1(config-router)#

*Mar 1 00:46:48.711: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 123: Neighbor 123.123.12

adjacency


adjacency

R1(config-router)#network 150.101.123.0 255.255.255.0

R2(config)#router eigrp 123

R2(config-router)#no auto


R2(config-router)#


adjacencyR2(config-router)#network 150.101.123.0 255.255.255.0

R3(config)#router eigrp 123

R3(config-router)#no auto


R3(config-router)#


adjacency




We can see that R1 has learned both R2 & R3 as expected.R1(config)#do show ip route eigrp


D 150.101.123.2 [90/2297856] via 123.123.123.2, 00:01:28, Serial0/0.123

D 150.101.123.3 [90/2297856] via 123.123.123.3, 00:01:28, Serial0/0.123

R2 & R3 however only learned the R1 route due to the split-horizon ruleR2(config)#do show ip route eigrp


D 150.101.123.1 [90/2297856] via 123.123.123.1, 00:01:28, Serial0/0.123

R3(config)#do show ip route eigrp


D 150.101.123.1 [90/2297856] via 123.123.123.1, 00:01:28, Serial0/0.123

We can disable split-horizon by using the no ip split-horizon eigrp <AS> command under theinterface.R1(config)#int s0/0.123

R1(config-subif)#no ip split-horizon eigrp 123R1(config-subif)#


split horizon changed


split horizon changed

Now if we check the routing table on R2 & R3 we can see we are learning all routes.R2(config)#do show ip route eigrp


D 150.101.123.1 [90/2297856] via 123.123.123.1, 00:04:29, Serial0/0.123

D 150.101.123.3 [90/2809856] via 123.123.123.1, 00:00:35, Serial0/0.123

R3(config)#do show ip route eigrp

150.101.0.0/32 is subnetted, 3 subnetsD 150.101.123.1 [90/2297856] via 123.123.123.1, 00:04:38, Serial0/0.123

D 150.101.123.2 [90/2809856] via 123.123.123.1, 00:00:43, Serial0/0.123

ccna routing labs

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