[c-nsp] MPLS TE to use 2 default routes?

[Phil Mayers]

So,

We have two connections to our upstream - same AS, both eBGP.

Our internal topology makes it a bit hard for us to use eBGP multipath 
to make use of both outbound; it's sort of like follows:

upstream1        upstream2
    |                  |
   R1 --------------- R2 --- stuff
    |                  |       |
   R3                 R4 --- stuff
    |                  |
    \------- R5 -------/

We have a high-traffic source attached to R4, and the IGP costs mean 
that R4 will never choose R1 as en exit point.

I am very (very) anxious to avoid tweaking IGP costs. We've had bad 
experiences with that in the past, and there's a whole other bunch of 
stuff hanging off R2 and R4 that this kind of tweaking might disturb. In 
addition, it would prevent e.g. R5 from using both default routes (there 
are high traffic nodes attached there too, though less so).

Is it at all sensible to build 2x MPLS TE tunnels from R4->R2 and 
R4->R1, and use these to make the eBGP routes multipath candidates? Am I 
setting myself up for pain?

Obviously the preferred option would be to re-do the topology, but at 
the moment we lack sufficient 10gig ports to do this, and it would mean 
either WDM or layer2 links (ugh).

Platform is 6500/sup720 running 12.2(33)SXJ1.

Thoughts welcome.

Cheers,
Phil