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New Member

routes advertising

Hi all,

I have a cisco router 7507 and i have connected to different service providers with different bandwidths. i have 2 class C ips with me. I want to advertise a subnet(pls note: NOt entire calls C) to service provider A. so that i can get all incoming traffic to that perticular subnet is from service proider A. Remaining Class C ips to other service providers. How can I do this. Can I use route-maps. or any other solutions for this. Kindly give me some examples if you can.


New Member

Re: routes advertising

You will first need to check with your service providers and see what routing protocol they are running. The standard Internet protocol is BGP. Next you will need to check with them and see if they will ALLOW you to do this. Many Service providers will not allow you to feed them another vendors route.

i.e. if you have and the supernet for this range belongs to AT&T

and you have yyy.yyy.yyy.yyy and the supernet for this range belongs to Sprint.

AT&T will most likely not allow you to feed them a partial Sprint route and vice-versa.



New Member

Re: routes advertising


thanks for the response. No need to worry with my service providers. They will take whatever I feed to them. The ip addresses are my own. And I can able to feed as a complete Class C. My question is how to feed a subnet of class C

to a service provider. The service providers are ready to accept my advertisements in whatever fashion.


New Member

Re: routes advertising

Of course you can do this. It depends a lot on the routing protocol that you're currently running. If you're using BGP4 then the process is pretty simple by adding 2 x static routes and advertise them to the appropriate neighbour. Don't forget that BGP only advertise what you want it to advertise. This is the beauty of BGP4. You can contact me direct on BTW, if you have been in contact with Cisco TAC then also let know what their methods are.

New Member

Re: routes advertising

of course you can do it, but u must know what routing protocol running between u with two ISP, if they running BGP4 with u, u can advertising two subnet int two BGP network command, and use route-map to two ISP.

For example:

route bgp xxx

network x.x.x.0 mask

network x.x.x.128 mask

nei y.y.y.y remote y

nei y.y.y.y route-map filterA

nei z.z.z.z remote z

nei z.z.z.z route-map filterB

acc 1 per x.x.x.0

acc 2 per x.x.x.128

route-map filterA

mat ip add 1

route-map filterB

mat ip add 2

if there is static route running between u with u ISP, u can ask them to advertising two subnet special.

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