Least cost routing (BGP) between multiple carriers over MPLS internal network

Currently we have a Frame network of six routers with two different ISPs,
each at a different site. We have an ASN and three of our internal
routers share BGP tables from the two providers. The remaining three
routers are spokes to this core.

The "core" is arranged in a triangle of Frame PVCS. So, we have an ISP
coming in two two different legs (AT&T on one, Sprint on the other) and
the three core routers share the BGP tables.

We've being sold a MPLS solution.

Our six routers will now be arranged as a full mesh. We're
keeping the two ISPs. Currently we use the ISPs as fail-over and Least
Cost Routing. Out MPLS vendor says the Label-to-route mapping is actually
in the PE and full Internet BGP routing information is too much for them.

My understanding of MPLS is limited, so I'm doing a fair amount of
reading. I understand, I think, there are mechanisms where the mapping can
be moved to the CE, thereby proving us with least cost routing across the
full mesh because the mapping burden is in our routers. The PE, then,
simply has a table of labels and routes based on those labels we
(somehow) attach. Is any of this true?

If my understanding s anywhere near correct, please point me to some
reference material. My overall impression is my MPLS vendor is trying to
screw me by removing functionality from my current network (LCR) and
inserting themselves as a "managed" solution, with associative increased
cost.

 

Do you really need full BGP? Normally prefixes of the direct ISP and his
customers + default (possible conditionally set by you based on presence of
certain prefix) should be enough, unless you're really into selecting which
sites you want to reach via one ISP and which via another. It's quite common
for PE routers to have only limited routing table (usually only prefixes
within providers own network) as they reach all destination via one or two
upstream routers. One of the possible solutions for you (if your providers
have such option) is to use multi-hop eBGP towards one of the providers
router that carries full-table.

Although you indeed could do mapping on your CE, no provider will agree up
on this due to security reasons (they don't want you to mess up service that
they provide). In Frame Relay world it would be comparable if you'd try to
get NNI connectivity with your ISP.

Managed solution assumes they'd also manage your CE. It's very common among
MPLS VPN providers. Actually it simplifies troubleshooting as there's no
ping-pong arguing whos side is at fault. ISP doesn't want to screw you, but
they might have not understood what exactly you want to achieve. Try to talk
to them and explain why do you want to have full routing and see what they
have to offer. Also try first to explain the problem to a manager in your
company, so that he/she can escalate the problem with your providers more
easier.

Regards,
iLya