[j-nsp] Traceroute for ECMP destinations

[Richard A Steenbergen]

On Wed, Sep 08, 2010 at 03:03:03PM +1200, Thedin Guruge wrote:
> Hi,
> 
> I'm wondering if it's possible to view all possible paths for an ECMP 
> destination from "traceroute" or "traceroute mpls ldp" 
> commands?default behavior seem to select one path arbitrarily.

The default behavior of classic traceroute is to send 3 probes per hop, 
and whichever links they happen to route over is what you will see. You 
might want to try "traceroute monitor" (mtr), which runs traceroute in a 
continuous loop. This will (eventually) do a pretty good job of finding 
all of the available ECMP paths, potentially at the expense of bumping 
up against the rather low TTL expiration rate limits on many routers.

-- 
Richard A Steenbergen <ras at e-gerbil.net>       http://www.e-gerbil.net/ras
GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)