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Community Member

about BGP routing


we have procured a 10MB internet Link with two local loop ( from different service provider) connecting to single ISP POP. output is ethernet handoff.

we will be making use of CISCO 3845 to terminate this link (on ethernet).

ISP's has provided us WAN IP's for both last mile and a LAN IP's and they are asking us to Run BGP on our Router so that when there is problem on one local loop other should takeover. Where as our network team says we will not be using BGP on this.

rather it could be achived with default routes.

Can any one pls inform abt this scenario, BGP on ISP and default route at customer place and 2 last mile(local loop) and output on ethernet handoff.

how the routing work




Re: about BGP routing


You can achieve the redundancy with the help of floating static routes.

But since the last mile is a ethernet handoff, the service provider is insisting to run bgp (or for that matter any routing protocol).

This is because static routes will not be flushed out of the routing table unless your line protocol goes down. Hence whenever there is a problem in one of the last mile beyond their ethernet handoff device, your protocol will remain up and traffic will be black holed.

When you run BGP, the traffic will fall back since there will be loss of neighbor information due to loss of keepalives.

Make sure you set your BGP policies right and receive only the default routes

Hope you have also considered that you will require an additional ethernet port to get connected to you LAN as well.

HTH, rate if it does


Community Member

Re: about BGP routing


Do you have your own AS number? Or the ISP wants you to use their AS number and become an iBGP neighbor?

You can ask the ISP to just advertise default routes to your router. Also, you can configure lots of attributes in BGP.

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