Redistribution

[mtechnology]

I want to run BGP on the core switches

and eigrp internally.

for this i am redistributing BGP into EIGRP so that i have a preferred path to the core.

Do i need to redistribute EIGRP back into BGP so that site 1 learns site 2 routes and vice versa.

IS there any other better way to achieve this without doing mutual redistribution

Attched is a network diagram

Thanks in advance

[mounir.mohamed]

Dear,

Yes you shall

Redistribute back the EIGRP routes to BGP OR using NETWORK commands under the BGP process to inject EIGRP routes into the BGP table to be advertised to other sites.

Router bgp 100

network 192.168.0.0 mask 255.255.0.0

please rate helpful posts.

Best Regards,

Mounir Mohamed

[Jon Marshall]

Hi

Considering the small number of subnets you have within each site i would use network statements under the BGP process as per the previous posters suggestion.

The only drawback to this is that if you add another subnet you must rememeber to add it under the BGP configuration, however it does give you more control and avoids any routing loops.

One thing to be aware of. For BGP to advertise out the networks that you add under the BGP config it must find the exact route in it's IGP routing table ie.

If you had two vlans

172.16.22.0/25

172.16.22.128/25

and you added "network 172.16.22.0 mask 255.255.255.0" under the BGP configuration it will not be advertised out because there is no route for 172.16.22.0/24 in the IGP table.

You can either advertise out the /25 subnets or you can use aggregate routes/static routes to Null0.

HTH

[mtechnology]

I have a large number of subnets and the networks shown were just an example.

I need to use redistribution and the problem i have been facing beacuse of the mutual nature is that the Edge router learns the far end route via the EIGRP process rather than the BGP. (i.e actually EIGRP winning over BGP)

I need to know what should be done to achieve this by redistribution and preventing the routing loops

[sundar.palaniappan]

Hi,

Mutual redistribution between EIGRP and BGP will simplify the configuration and is much more scalable. However, there is one potential problem which you alluded to in your original post, routing loop/routing feedback. Since you have multiple points of redistribution it can cause routing loops/routing feedback and that's undesirable.

However, there is a way to address this problem. Tag the native EIGRP routes at the point of redistribution into BGP and on the other end redistribute BGP into EIGRP only those routes that match the tag. This would prevent routing feedback i.e native routes for one domain wouldn't be redistributed back into the same domain.

HTH

Sundar