[c-nsp] Route redistribution and selection

[Ivan Pepelnjak]

@Luan: Thanks for the link :))

@Joe: if you have EBGP sessions with the core MPLS VPN network, you're
losing the BGP cost community (resulting in the EIGRP-related redistribution
issues). It might be possible to tweak the WEIGHT attribute on the PE
routers (the routes redistributed into BGP have very high weight and are
thus never replaced by other BGP routes), but you'd probably need
access-lists to select the backup routes.

Ivan
 
http://www.ioshints.info/about
http://blog.ioshints.info/

> -----Original Message-----
> From: Luan Nguyen [mailto:luan at netcraftsmen.net] 
> Sent: Thursday, August 13, 2009 3:44 PM
> To: 'Joe Maimon'; 'cisco-nsp'
> Subject: Re: [c-nsp] Route redistribution and selection
> 
> You might want to check this link out:
> http://wiki.nil.com/Multihomed_MPLS_VPN_sites_running_EIGRP
> 
> Regards,
> 
> -------------------------------
> Luan Nguyen
> Chesapeake NetCraftsmen, LLC.
> http://www.netcraftsmen.net
> ------------------------------
> 
> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net
> [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Joe Maimon
> Sent: Thursday, August 13, 2009 9:04 AM
> To: cisco-nsp
> Subject: [c-nsp] Route redistribution and selection
> 
> 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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