RIP — A distance vector interior routing protocol

IGRP — The Cisco distance vector interior routing protocol (not used nowadays)

OSPF — A link-state interior routing protocol

EIGRP — The Cisco advanced distance vector interior routing protocol

BGP — A distance vector exterior routing protocol

2ITCN

Distance vector routing in general /30 addressing on serial linksRIP version 2

◦Problems◦Configuration◦Troubleshooting

IGRP overview

3ITCN

4ITCN

To reduce routing loops and counting to infinity, RIP uses the following: ◦ Counting to infinity ◦ Split horizon ◦ Poison reverse ◦ Holddown counters ◦ Triggered updates

5ITCN

Only ever 2 hosts on a serial link No need to waste a whole /24 (Class C)

address – use RFC 1918 Solution is to use a small subnetwork /30 (255.255.255.252) /30 has FOUR addresses, two of which are

for the serial interfaces What are the other TWO unused addresses

called?

6ITCN

•Routing Information Protocol

•It was first defined in RFC 1058 (1988)

•RIP Version 2 (RFC 2453)

•RIP has been adapted, known as RIPng (RFC 2080, 1997), for use with IPv6

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8ITCN

Using router rip and network commands to enable RIP

Enabling RIP on an IP-addressed network Monitoring IP packet flow using the show ip protocol command

The show ip route command

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10ITCN

11ITCN

IP classless only affects the operation of the forwarding processes in Cisco IOS Software; it does not affect the way the routing table is built.

When this feature is disabled, any packets received that are destined for a subnet that numerically falls within the router’s subnetwork addressing scheme are discarded.

12ITCN

Rochester#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 N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP i - IS-IS, 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

R 192.168.1.0/24 [120/1] via 192.168.100.2, 00:00:14, Serial0/0 192.168.100.0/30 is subnetted, 1 subnetsC 192.168.100.0 is directly connected, Serial0/0

13ITCN

Rochester#show ip protocolsRouting Protocol is "rip"Sending updates every 30 seconds, next due in 22 secondsInvalid after 180 seconds, hold down 180, flushed after 240Outgoing update filter list for all interfaces is not setIncoming update filter list for all interfaces is not setRedistributing: ripDefault version control: send version 1, receive any version Interface Send Recv Triggered RIP Key-chain Serial0/0 1 2 1 Automatic network summarization is in effectMaximum path: 4Routing for Networks:

192.168.100.0Passive Interface(s):Routing Information Sources:

Gateway Distance Last Update192.168.100.2 120 00:00:25

Distance: (default is 120)

14ITCN

Rochester#show ip interface FastEthernet0/0 is up, line protocol is up (connected) Internet protocol processing disabledFastEthernet0/1 is administratively down, line protocol is down (disabled) Internet protocol processing disabledSerial0/0 is up, line protocol is up (connected) Internet address is 192.168.100.1/30 Broadcast address is 255.255.255.255 Address determined by setup command MTU is 1500 bytes Helper address is not set Directed broadcast forwarding is disabled Outgoing access list is not set Inbound access list is not set Proxy ARP is enabled Security level is default Split horizon is enabled ICMP redirects are always sent ICMP unreachables are always sent ICMP mask replies are never sent IP fast switching is disabled IP fast switching on the same interface is disabled etc etc………..

15ITCN

Rochester# debug ip ripRIP protocol debugging is onRochester#RIP: received v1 update from 192.168.100.2 on Serial0/0 192.168.1.0 in 1 hopsRIP: sending v1 update to 255.255.255.255 via Serial0/0 (192.168.100.1)RIP: build update entries network 192.168.50.0 metric 1RIP: sending v1 update to 255.255.255.255 via FastEthernet0/0 (192.168.50.1)RIP: build update entries network 192.168.1.0 metric 2 network 192.168.100.0 metric 1RIP: received v1 update from 192.168.100.2 on Serial0/0 192.168.1.0 in 1 hops

16ITCN

Load balancing is a concept that allows a router to take advantage of multiple best paths to a given destination.

17ITCN

18ITCN

A router running RIP can receive a default route via an update from another router running RIP.

Another option is for the router to generate the default route itself.

The static routes can be removed using the no ip route global configuration command.

The administrator can override a static route with dynamic routing information by adjusting the administrative distance values.

19ITCN

•A classful routing protocol

•Never used today!!•No field for a subnet mask

•Classful protocols have become less popular as they are wasteful of IP address space

20ITCN

Triggered update is sent immediately in response to some change in the routing table

21ITCN

Originally defined in RFC 1058. Key characteristics include the following: ◦ A distance vector routing protocol.◦ Hop count is the metric for path selection.◦ If the hop count exceeds 15, the packet is discarded.◦ By default, routing updates are broadcast every 30 seconds.

22ITCN

RIP is simple to setup Show commands for checking RIP Debug for showing detailed running

information IGRP not really used any longer

23ITCN

http://en.wikipedia.org/wiki/Routing_Information_Protocol

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