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New Member

peering with egbp from my network

Hi all

when peering with 2 isp's from my network, why do I have to run IBGP on my edge routers, is this needed to that if one external link fails, the other ibgp peer can learn the routes ?

6 REPLIES

peering with egbp from my network

Yes, this is a dynamic method for the one Edge router with the failed internet link to route the traffic to the other router with active internet link. The router with the failed internet link knows the internet routes via iBGP advertised by the other edje router. The iBGP peering between edje routers can also be used if you want a balance of the traffic.

HTH,

Vasilis

New Member

peering with egbp from my network

hi there

what do you mean ibgp peering between the edge routers if I want to balance traffic ?

peering with egbp from my network

Hi carl,

If you have 2 edge routers you can configure the one edge router to not send all the internet traffic via the direct internet link but to prefer to send a percentage of the internet traffic to the other edge router and then to the internet. This could be needed if you have one link with higher bandwidth than the other. You can achieve this by modyfing the BGP attributes to prefer the iBGP to the eBGP learnt routes for some subnets.

HTH,

Vasilis

New Member

peering with egbp from my network

can you give me example, do you mean doing a route map for certain prefixes ?

peering with egbp from my network

Hi Carl,

You can find an example with detailed configuration to the next link

http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a00800945bf.shtml

Please, read the section

Load Sharing When Dual-Homed to One ISP Through Multiple Local Routers

" With this type of load sharing, traffic to specific networks, on the basis of predefined policies, travels through both links. Additionally, each link acts as a backup to the other link, in case one link fails"

iBGP between the edge routers is needed in order to achieve load sharing.

Hope that helps,

Vasilis

peering with egbp from my network

Yes, this is what i mean

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