[c-nsp] CEF Tuning with ECMP?

[John Neiberger]

I'm starting another thread because the topic is migrating. To
simplify, we have a 7600 with SUP720-3BXL connected via four routed
links to a 4948. The bulk of the traffic on this network is multicast
traffic flowing from the 4948 to the 7600 (and onward from there). In
order to get the best load sharing over those four links, what is the
recommended CEF tuning and ECMP configuration?

I ask because we seem to be running into ECMP polarization and/or CEF
polarization. We have already decided that we need to be using
s-g-hash next-hop-based for ECMP. We're using s-g-hash basic right
now. But what about CEF? Do we need to tune CEF along with tuning ECMP
for this to work properly? We want the most even distribution of
traffic possible. As it is right now, we're seeing serious unequal
load sharing. In some cases all of the traffic is going over one link
and not even using the other three.

Do any of you know the recommended CEF parameters in a situation like this?

Thanks,
John