[c-nsp] Route redistribution and selection

Joe Maimon jmaimon at ttec.com
Thu Aug 13 09:04:27 EDT 2009


We are having a problem where routes originated by the customer because 
of their backup paths are preventing the mpls bgp routes from being 
installed and used on the PE.

Customer has an eigrp routed network.

We are hosting a bgp mpls network for the customer.

At the Customer's HQ PE router, we talk eigrp to the customer.

The customer has an alternate path to the sites served by the bgp mpls 
network.

We allow redistribution of eigrp routes into bgp to advertise to the 
mpls bgp sites. This includes the sites known prefixes themselves, due 
to the potential for the backup path becoming the better/only one.

We redistribute the bgp routes for the mpls sites into eigrp.

Normally this is a fairly common setup and works very well, and has for 
quite some time with this customer.

However, on one PE we have been having issues where the customer backup 
path eigrp routes are installed into the PE routing table, the bgp 
routes show the originated via eigrp routes as the best and used path 
our of both the local originated via eigrp and the P mpls bgp learned route.

The current fix is to flap the customer eigrp connection or have the 
customer withdraw the backup path routes.

The P routers and the PE routers are an ebgp connection. The eigrp route 
has an admin distance of 170 and the ebgp route when installed has an 
admin distance of 20.

We have tried setting the weight, local preference, metric of the mpls P 
  router prefixes to cause the route to be preferred over the 
redistributed locally from eigrp route.

The PE router running rsp-jk9o3sv-mz.124-18a.bin

Any insight would be greatly appreciated.

Thanks,

Joe


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