Redistribution (CCNP)

Seite 1

Redistribution

- Routes are taken from routing table of the Source routing protocol for redistribution and then added to topology table of destination routing protocol

- Redistribute connected routes running source routing protocol even if that interface is passive

Redistribution into EIGRP:

- for connected routes, router will pull the metric values(bandwidth and delay) from interface

- for other routes, we need to specify metric

- match: in case of OSPF, we can match different route types like internal,external,NSSA

-tag :

- if metric is not specified,

3 ways to set EIGRP metric:

1) default-metric: [bw] [delay] [reliability][load][mtu] EIGRP subcommand

- this sets default metric

2) metric command : redistribute RIP/OSPF

3) Route-map:

match and set metric

order of preference:

metric in route-map > redistribution command > default metric

- redistribute routes will show as EIGRP external routes

#show ip eigrp topology

Type 4 LSA: External summary

-ABR created type 4 LSA

- this is to identify for ASBR for routers which are in different Areas

- every ABR creates type 4 LSA

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Redistribution into OSPF

- if redistributing from BGP, it take cost of 1 . for other cost 20

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Preventing loops:

1) change metric

2) make sure seed metric is high for redistributed routes

2) change AD

- AD change is local to a router

EIGRP:

#distance EIGRP <internal> <external>

# distance <value> <ip src add> <wildcard masks>

- with EIGRP external routes, we can change AD for all routes or none. no selected routes

OSPF

#distance ospf <external > <intra area> <inter area>

#distance <value> <ip src add><wilcard bits>

- ip src add : advertising source ID

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