RE: A possible solution for source-based site-exit routing

["Aldrin Isaac" <aisaac@bloomberg.com>]

Hi all,

Since I didn't get any comments on my previous email, I have tried to
present a brief explanation of how I arrived at it:

(1) If a multi-address host were connected such that each PA addressed
interface was directly connected to the network of the ISP who
assigned that interface's address, then we've reduced the problem down
to the similar level of simplicity as the home-pc that is connected to
a dsl ISP and a cable ISP.  This is the optimum environment for
host-based multi-homing solutions.

(2) However, since enterprises aren't going to do that for more
reasons than are worth discussing here, we could probably achieve the
same results by creating virtual topologies within the enterprise.
This could be done by placing each interface of every host on a VLAN
that is associated to the ISP that assigned its prefix.  The router
interface which is connected to that VLAN would be part of an MPLS VPN
to which the ISP is also connected.  This creates a similar
environment for the host as in (1).

(3) However, even (2) is a little too operationally complex.  But, if
we take the VPN routing tables in (2), and find a way to route-based
on the VPN only when the source address constraints require us to do
so, then we have what I described in my previous email.

If this idea has been presented and shot down in the past, I would
appreciate if someone could tell me so I can drop it.

Thanks

-- aldrin