[c-nsp] Standard ping vs MPLS ping

[FF]

I've been seeing some "cosmetic" ping losses, as high as 4% when traffic is
transit'ing a particular router, or any of the routers directly connected
to it. [all 6500's running IOS SXH5->8b]. Routers "two hops" away from this
particular router have no cosmetic ping losses. The packet losses are not
sticky to any particular port, blade or wire. They appear on third party
circuits, as well as [lit] dark fiber pathways.

When I say they are cosmetic, traffic flows absolutely wonderfully through
them (at the same levels before this problem showed up).

The equipment is MPLS enabled, and mpls ipv4 pings show absolutely ZERO
losses. So "normal" ping is lossy and mpls ping isn't.

So the first question is, is "ping mpls ipv4 xx.xx.xx.xx/32 repeat 1000"
differently handled than "ping xx.xx.xx.xx repeat 1000" is the former run
in hardware and the latter run on the CPU?

The problem *looks* like a control plane issue, but the CPU isn't spikey
(the router at the center of this is averaging about 10-15% cpu
utilization) and the problem doesn't seem to change much based on
time-of-day.

Was going to open a TAC ticket, but was wondering if there is a sensible
"oh, look at this, and you'll see you need to see CoPP to xx" direction to
go in.

If its not a control plane issue, then clearly mpls is hiding/protecting
the traffic from it, but I'm at a loss for what could be causing it.

thanks in advance!

FF

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FF