Dynamic Routing

Routing Information Protocols (RIP)

RIP is using the algorithms known as “distance vector algorithms”. They are sometimes known as Ford-Fulkerson algorithms and the term Bellman-Ford is also used. It send the complete routing table out to all active interface every 30 second.RIP only uses hop count to determine the best way to a remote network. The default hope count of 15 by default, its meaning that 16 is deemed unreachable.RIP suitable for small medium network.RIP version 1 uses only support classful routing which means that all device in the network must use the same subnet mask information.RIP version 2 provide is classless routing which means that it does send subnet mask information with the routing updates.RIP v2 called prefix routing.

RIP using Timers

Routing update time: Typicaly-30 sec between periodic routing update in which the router send a complete copy of its routing table out to all neighbor.
Route Invalid timer: the length of time that must elapse 180sec before router determines that route has become invalid.
Hold-down Time: Its sets the amount of time during which routing information is suppressed (180 Sec).
Route Flush time: Set the time between a route becoming invalid and its removal from the routing table (240 sec).

Configuring RIP Routing

After assigning the IP address to the router interface, we should configure RIP routing information from router global configuration mode

To configure RIP v1

Router# router rip
Router# network <then destination network IP address eg;>

To configure RIP v2

Router# router rip
Router# network <then destination network IP address eg;>

Router# version 2

To verify the RIP Routing Table

Router# show ip route (it will give you all the routing information)
Router# Show ip interface brief (It will give you all the router interface status information)
Router#Show rip status

Interior Gateway Routing Protocols (IGRP)

IGRP is a Cisco Proprietary distance-vector routing protocol. Its means that your entire router must be Cisco routers. IGRP has a maximum hope count of 255, the default will be 100.This is helpful to medium network and solve the problems of 15 hops being the maximum possible in a RIP network. IGRP also uses metric counts to determine the best route to an internetwork. This is called a composite metric. It also uses Reliability, Load and MTU but they are not used by default. The main difference between IGRP and RIP is that when you configure IGRP you should supply the AS (Autonomous Number) number. All routers must use the same number in order to share routing table information. It has administrative distance -100. The major alternative to IGRP is Enhanced IGRP (EIGRP) and a class of algorithms referred to as SPF (shortest- path first).

The metrics used by IGRP include the following:

Topological delay time
Bandwidth of the narrowest bandwidth segment of the path
Channel occupancy of the path
Reliability of the path

IGRP Timers:

Update time is – 90 sec
Invalid time is -240sec
Hold-down time is -250
Flush time-630sec

Configuring IGRP Routing

When you configure IGRP you should specify the Autonomous system Number .All router within an autonomous system must use the same AS number otherwise they won’t communicate with the routing information.

Router# router igrp 10 (Autonomous number is -10)
Router# network <Destination network IP eg;>

To verify Configuration:

Router# show ip route – It displays all the routed protocols and the interface with Enabled protocols.

Router# show ip protocols – It displays the protocol that are configured on the router

Router# debugs ip igrp events –  This command send routing updates as they are sent and received on the router to the console session.
Route Flush time: Set the time between when a route becomes invalid and its removal from the routing table