[c-nsp] ECMP failing over time?

[John Neiberger]

We converted several connections last week from Etherchannels to
routed links with ECMP. We verified that traffic was load-sharing over
those links after making the change. Now, a week later, we are seeing
instances where traffic is preferring one or two links out of each
"bundle". In some cases all the traffic is flowing over a single link
in a four-link setup. This is overloading those connections and we
can't figure out why. We are using s-g-hash basic. Should we switch to
s-g-hash next-hop-based?

This is causing production issues right now, so I've opened up a TAC
case, but I thought I'd ask here, as well, just in case someone had
seen this before.

Thanks,
John