Monday, December 29, 2008

IE Vol 1: VPNv4 Route Reflection Complete

This was an interesting lab that took a heck of a lot of time to just reconfigure the topology.

Essentially, the configuration ends up with two separate route reflectors--one for ipv4 routes and one for vpnv4 routes. Amazingly, no real complex configuration is required. There's no need to mess with clusters or anything like that. Instead, simply configuring the route-reflector-clients under vpnv4 instead of directly under the bgp process takes care of it.

I did run into two issues due to simple mistakes. First, one of my PE routers showed all MPLS labels as being untagged. This was due to me forgetting to turn on cef on one of the P routers.

Second, one of my CE routers was not learning any RIP routes. This issue actually threw me for a loop for a bit. It turned out that on the PE router I didn't set RIP to version 2 under the appropriate address-family. By default, rip sends version 2 and receives versions 1 and 2. But when version 2 is specified, rip only sends and receives version 2.

Since the PE router did not specify, it received the version 2 routes from the CE router and entered them into the routing table. It also redistributed its bgp routes into RIP and sent them as version 1.

Since the CE router specified version 2, it ignored the version 1 routes sent by the PE router.

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