Thursday, October 8, 2009

Solution Of Multihomed Redundancy

Most of the answers received for quiz is that configure the secondary route on PE2 with higher metric for CE1 lan in case of static routing or configure dynamic routing. But I am more concerned towards the static routing solution. If static routes are configured on secondary PE2 with higher metric will not come into play because the local originated weight of route is 32768 but the route which is received by MP-iBGP is having weight of 0, so the metric will not play and by default traffic forwarding for CE1 lan will happen from PE2 back door link configured for CE1. The higher metric route will be selected during that time when it is being received by multiple sources. To overcome this problem I have tested the solution by configuring the route map with weight 0 for CE1 lan. This route map is called under address family of vpn with redistribute static. Once this will be done one can see the weight of local originated route will become 0. There after configure the static route for CE1 lan with metric more than 200. Once this will be done PE2 will receive the routes from RR and local originated route and compare both the routes having same weight and then check for the lowest AD. The lowest AD configured route is receiving by RR, os it will be preferred and traffic will start flowing by PE1 instead of PE2. Once the PE1 primary link fails, that floating static route will add in the table.
For dynamic back door links refer to the previous post of BGP as PE-CE with back door link and it's simulated results.

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