Redistribution:

Redistribution is a process used to make communication between two different routing protocols and also two different Autonomous Systems in IGRP and EIGRP protocol.

Redistribution can be performed in intermediate router only. Intermediate router means "it is a router where two different protocols or two different AS is enabled".

Example for redistribution with different protocols and commands:

Assume RIP and EIGRP is enabled in this router.

router(config)#router rip

router(config-router)#redistribute eigrp 10 metric 5

(The range of metric is 0-16, it is RIP metric). Do you know why metric is specified? we are redistributing EIGRP in RIP, does RIP knows how EIGRP calculates metric? no. that's y metric is specified, whatever metric it receives with EIGRP update will be converted into the metric what is specified.

router(config-router)#exit

router(config)#router eigrp 10

router(config-router)#redistribute rip

(The range of metric is 1- 4294967295, it is EIGRP metric).Do you know why metric is specified? we are redistributing RIP in EIGRP, does EIGRP knows how RIP calculates metric? no. that's y metric is specified, whatever metric it receives with RIP update will be converted into the metric what is specified.

Example for redistribution with different AS and commands:

Assume IGRP 20 and 30 is enabled in this router.

router(config)#router igrp 20

router(config-router)#redistribute igrp 30

Here, it is not necessary to specify the metric, y because both are igrp(same protocol).

router(config-router)#exi

router(config)#router igrp 30

router(config-router)#redistribute igrp 20

Here, it is not necessary to specify the metric, y because both are igrp(same protocol).