Subject: Multi-path Routing

From: Kishore <[email-masked]>
Date: Mon, 01 Nov 1999 12:05:24 -0600

Hi,
    draft-ietf-mpls-cr-ldp-02.txt  states
"constraint-based route is calculated at one point at the edge of
network based on criteria, including but not
    limited to routing information"
In case of sinlge path, the constraint-based routing table is readily
made available by CR algorithms and ingress node can determine the path
which satisfies the criteria and thus signal for resources along that
path.
But in the case of multi-path routing, is there any proposed method to
determine which "set of paths " (multi-path) satisfies the given
criteria so that the ingress node can do signaling ...
Ingress node should consider the links that might be common on the
parallel paths that are under consideration as both might be using same
resources... on a particular set of links or routers.

For example consider a bandwidth constriant:
A->B->C->D->F
A->E->C->D->F
let C-> D have 50Mbps
and both possible paths for A->F are with bandwidth constraint of 50Mbps
.  Then we are using C->D twice.
This might be solved by calculating each path based on residual
bandwidth of the link after a previous computation and then parallel'ing
the paths.. Doing this for all the nodes  !!!
Is there any better way to do this?

thnx,
- kishore