Bgp & Eigrp redistribution

Answered Question
Dec 30th, 2008

I am having a problem while redistribution of BGP into EIGRP & the other way round. The problem is when i redistribute bgp into eigrp i get only the 1.1.1.0/24 network from R1 the rest of the networks from bgp don't appear in the routing table. The EIGRP route of 6.6.6.0/24 does appear in the routing table of BGP

Regards

Ryel.

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Correct Answer by Giuseppe Larosa about 7 years 11 months ago

Hello Ryel,

seeing the routes make me of think of the following

bgp redistribute-internal

To configure iBGP redistribution into an interior gateway protocol (IGP), such as IS-IS or OSPF, use the bgp redistribute-internal command in address family or router configuration mode. To return the router to default behavior and stop iBGP redistribution into IGPs, use the no form of this command.

bgp redistribute-internal

no bgp redistribute-internal

Syntax Description

This command has no arguments or keywords.

Defaults

IBGP routes are not redistributed into IGPs.

see

http://www.cisco.com/en/US/docs/ios/iproute/command/reference/irp_bgp1.html#wp1014183

BGP routes from confederations are treated as iBGP for some aspects and as eBGP for others.

Try the lab without BGP confederations first and see if the above command is needed to achieve the desired result.

Later you can add again BGP confederations.

Hope to help

Giuseppe

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Giuseppe Larosa Tue, 12/30/2008 - 10:24

Hello Ryel,

you have decided to use BGP confederations but BGP confederations commands are missing on R1.

I think at least bgp confederation identifier is needed everywhere

see

http://www.cisco.com/en/US/docs/ios/iproute/command/reference/irp_bgp1.html#wp1012480

second note:

BGP routes learned via iBGP have AD 200 and are not preferred over IGP routes like OSPF (AD 110) or EIGRP (AD 90)

the redistribution of BGP into EIGRP will pass only the routes present in the BGP table that are also installed in the IP routing table.

So all iBGP routes overriden by IGP routes are not passed to EIGRP.

Hope to help

Giuseppe

ryel.dsouza Tue, 12/30/2008 - 10:49

Oh!! sorry the bgp confideration command on R1 was not there but i was playing around with the config to see if other things were going to work.

router bgp 4000

no synchronization

bgp log-neighbor-changes

bgp confederation identifier 2000

network 1.1.1.0 mask 255.255.255.0

redistribute eigrp 1 metric 2000

neighbor 13.0.0.2 remote-as 4000

neighbor 13.0.0.2 next-hop-self

This is the config on R1 now but still the other bgp routes are not coming in the routing table also i have sync tured off.

Giuseppe Larosa Tue, 12/30/2008 - 11:22

Hello Ryel,

I would suggest you to try the lab without any BGP confederations first with some iBGP and some eBGP sessions.

Track for each route which routing protocol provides the best route to the IP routing table maintaner process in terms of AD and metric

[AD metric]

expect that only B routes in R1 router IP routing table will be passed to EIGRP so some BGP routes you see in sh ip bgp can be missing

or also compare

sh ip bgp

sh ip route bgp

on router where BGP to EIGRP redistribution is performed

Hope to help

Giuseppe

ryel.dsouza Tue, 12/30/2008 - 11:47

I will do the lab without confederation but at the same time have a look at the "sh ip bgp" & "sh ip route" on R1.

I don't find anything wrong. Do let me know if something missed my eye ???

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Correct Answer
Giuseppe Larosa Tue, 12/30/2008 - 11:57

Hello Ryel,

seeing the routes make me of think of the following

bgp redistribute-internal

To configure iBGP redistribution into an interior gateway protocol (IGP), such as IS-IS or OSPF, use the bgp redistribute-internal command in address family or router configuration mode. To return the router to default behavior and stop iBGP redistribution into IGPs, use the no form of this command.

bgp redistribute-internal

no bgp redistribute-internal

Syntax Description

This command has no arguments or keywords.

Defaults

IBGP routes are not redistributed into IGPs.

see

http://www.cisco.com/en/US/docs/ios/iproute/command/reference/irp_bgp1.html#wp1014183

BGP routes from confederations are treated as iBGP for some aspects and as eBGP for others.

Try the lab without BGP confederations first and see if the above command is needed to achieve the desired result.

Later you can add again BGP confederations.

Hope to help

Giuseppe

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