[c-nsp] BGP vs OSPF (CE -> PE)

[Vitkovský Adam]

It's because intra-area LSAs are preferred compared to inter-area LSAs. 
The super-backbone(MP-BGP->OSPF) introduces LSAs from the remote site as Type-3 into the LSDB of a local PE and if the local PE happens to have a Type-1 LSA from a directly connected link than that one is preferred. So you can either make both LSAs to appear as Type-1 using sham-link or you can make both to be type-3 using different areas on each site. 

Or you can use BGP as everyone else and can forget about all this mess above. 

adam

> -----Original Message-----
> From: cisco-nsp [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of
> CiscoNSP List
> Sent: Wednesday, June 18, 2014 7:12 AM
> To: cisco-nsp at puck.nether.net
> Subject: [c-nsp] BGP vs OSPF (CE -> PE)
> 
> Hi Everyone,
> 
> We typically use OSPF (CE/PE) so customer can advertise routes into their
> VRF - We have issues with failover (When customer site has 2 links) but the
> links go to different PE"s of ours (We only have agg's from carriers on certain
> PE's)..
> 
> eg.
> 
> Customer(vrf) has a site(foo) connected to PE A + B (PE B is "failover" link)
> 
> Same customer has another site(bar) connected to PE B.
> 
> Traffic from site "bar" to "foo" will go via PE B, which is not what we
> want...we have manipulated this to work via longer subnets (i.e. failover link
> advertising a /23 instead of a /24), but this isnt always feasible.
> 
> Would BGP(Instead of OSFP) help in this situation...i.e. Can we manipulate
> how the routes are advertised(PE A/B) within the vrf more easily if the CE
> advertises via BGP vs OSPF? Or any other suggestions?
> 
> Cheers
> 
> 
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