mpls l3vpn sham link for ospf when back door exists

I just did a lab with this in it.

Am I correct in my understanding that the sham link is for making the mpls
provider core look like an *intra-area* connection such that both pe's ospf
vrf process is connected together as intra-area on behalf of the CE ospf
area at both pe locations?

It was pretty nice how it worked. Then I see that all I had to do at that
point was a typical ospf interface cost change to make the path via the sham
be more attractive to the ce routers. So, the backdoor connection between
the ce's I had to make it higher ospf cost on those respective interfaces.

Also, the sham was created between the (2) pe's using a loopback interface
which was advertised between the (2) pe's respective ce-facing ipv4 vrf
address family. .I got curious and wanted to know if I could've config'd
that sham using the preexisting phy ints that I connected via pe-ce. It
didn't work. The sham link wouldn't come up. Did it have something to do
with the preexisting phy ints were advertised into local ospf on the ce side
as lsa type 2's (net links) ?

Aaron

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Received on Tue Mar 06 2012 - 10:44:21 ART