[c-nsp] as-override

[Dean Smith]

> If a network is so
> large/important that one can't "just" change AS, one should consider
> trying to obtaining a real AS.
>

The constraint in my case is the MPLS product I can buy. Each resilient 
access is configured as its own private AS for BGP. The core AS uses the SP 
registered AS. I have no option but to have a route table full of <private 
as>.<sp mpls as>.<private as>

I have no option to impose a single consistent AS on my Supplier- and 
realistically only the one supplier for size of network I need in my market 
(Full national coverage of the uk). As it happens we do have our own 
registered AS we use for our internet facing presence and a limited number 
of external  peerings. But again I have to jump through hoops to present all 
routes as that single AS after all no-one wants to see which SP I use for my 
MPLS core or how many private AS I have. Given I can change/amend/delete/add 
almost every other metric in the BGP decision process it seems strange I 
dont have full control to manipulate the AS path aswell.

still life would be dull if it was all easy.

Dean