bgp redistribute into ospf, not working

[cnicules]

Hi,

first i did a search and found this http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Network%20Infrastructure&topic=WAN%2C%20Routing%20and%20Switching&CommCmd=MB%3Fcmd%3Ddisplay_location%26location%3D.1ddd2cad

and learnd that as my bgp is a ibgp he will not redistribute into ospf, ok, i use the bgp internal-redistribute, and it works, but i realise that i have the same config elswhere where it works without the bgp internal-redistribute, so i check and it's not quite identical, its with vrfs, so here are.

first

router ospf 1

redisp bgp 100 subnets

network ...

router bgp 100

neighbor x.x.x.x remote-as 100

and a route learned from bgp is not advertised in ospf, if i put in bgp the bgp redistribute-internal, the route is advertised. Logically if i change the as numbers and this way i have a ebgp it will work without the bgp internal-redisp, right?

ok, the second

is identical except that the ospf is into a vrf and the bgp is mpbgp

router ospf 1 vrf vpn_toto

redisp bgp 100 subnets

network ...

router bgp 100

neighbor x.x.x.x remote-as 100

neighbor x... send extended communities

...

and here without the bgp redisp-internal, the routes learned from bgp are advertised into the ospf, and a show ip ro <route> show the "internal bgp"

i don't understand?

is the fact of having the vrf/mpbgp make the internal igp redistribution by default?

thanks for info

ciprian

[mheusinger · Accepted solution]

Hi ciprian,

Yes, indeed, having the VRFs makes the big difference. The reason is that in a MPLS VPN - which is implemented using the VRFs - BGP is meant to transport the customer IGP routing information. So a customer router will announce the customer networks to the provider (edge) router and between the provider edge routers BGP is used to distribute the routing info.

As such BGP-OSPF redistribution is the desired behaviour in such an environment.

For an internet ISP this is not the desired behaviour - so another command is needed to implement redistribution.

Hope this helps! Please use the rating system.

Regards, Martin

[cnicules]

thanks, i like when my feelings are right :P