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New Member

BGP to EIGRP redistribution and filtering

I am on the customer side of BGP with my carrier

Looking for the best way to filter the carriers networks(our BGP interfaces and neighbors) from being redistributed from BGP to EIGRP

Thanks

8 REPLIES
Gold

Re: BGP to EIGRP redistribution and filtering

Hi there,

route-maps and prefix lists.

HTH,
Soroush.

Hope it Helps!

Soroush.
New Member

BGP to EIGRP redistribution and filtering

Soroush - thanks for the reply. I was hoping for a little more info. Anyone have an example or link explaining this a little more?

Gold

BGP to EIGRP redistribution and filtering

you can control what routes be redistributed into your EIGRP instance from BGP, with route-maps.

you select the routes you want or you dont want to be redistributed with prefix-lists, then using route-maps you call those prefix-lists and Allow or deny them. then you apply the route-map while configuring the redistribution.

example, if i dont want network 172.16.55.0/24 and 192.10.1.100/26 to be redistributed into my EIGRP:

ip prefix-list EIGRP permit 172.16.55.0/24

ip prefix-list EIGRP permit 192.10.1.0/26

route-map BGP_EIGRP deny 10

match ip address prefix-list EIGRP

route-map BGP_EIGRP permit 20

router eigrp 100

redistribute bgp 20 route-map BGP_EIGRP metric xxxx

Also keep in mind to setup appropriate metric for the routes comming from BGP.

useful link: http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a008009487e.shtml#ex2

if you had further questions plz ask

plz Rate if it helped,

Soroush.

Hope it Helps!

Soroush.
New Member

BGP to EIGRP redistribution and filtering

Soroush - thanks for the explanation. A few questions. on the prefix-list its permit and it gets denied on the route map, is that correct ? Also, is route-map BGP_EIGRP permit 20 to permit all other routes ?

Thanks

Gold

BGP to EIGRP redistribution and filtering

yes, for this task you permit network perfixes (based on ur decision) and the prefix-list gets denied in the route-map, then the route-map is assigned to the redistribution process.

route-maps (like access-lists) have an implicit deny at the end. so whenever u r using route-maps to filter routes, you have to have this in mind.

however, if you want to let a few subnets to be redistributed in the EIGRP, i suggest u do the opposite, permit the ones u want and deny all other.

HTH,

plz Rate if it helped.

Soroush.

Hope it Helps!

Soroush.
New Member

BGP to EIGRP redistribution and filtering

but in this case route-map BGP_EIGRP permit 20 allows everything else ??

Gold

BGP to EIGRP redistribution and filtering

yes it allowes everything else.


Soroush.

Hope it Helps!

Soroush.
New Member

BGP to EIGRP redistribution and filtering

Ok - thanks for the info

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