[c-nsp] PA-GE - Incrementing Ignored and Overrun Errors

[Gregory Boehnlein]

Hello,
	We have a 7507 w/ Dual RSP-4's running 122-25.S12. It's been up and
working w/out a problem for 50 weeks at this point. Over the past few days,
our Gig-E fiber trunk to Level-3 has been exhibiting an unusual amount of
packet loss when our BGP sessions are up. From a traffic perspective, we are
only sending/receiving about 30 Megabits / second across this interface.
When we drop the BGP session w/ X/O and ping across to their BGP peer,
everything is fine. When we have BGP enabled, there are no input errors, but
we do see incrementing numbers in the Overrun and Ignored fields. According
to the Cisco Ethernet troubleshooting documentation, this means the
following:

Overrun Errors
--------------
Description: The number of times the receiver hardware was unable to hand
received data to a hardware buffer.
Common Cause: The input rate of traffic exceeded the receiver's ability to
handle the data.

And..

Ignored Errors
--------------
Description: Cisco IOS sh interfaces counter. The number of received packets
ignored by the interface because the interface hardware ran low on internal
buffers.
Common Causes: Broadcast storms and bursts of noise can cause the ignored
count to be increased.

Any suggestions on where to look? Level 3 is dispatching to do end-to-end
testing on their Fiber interconnect. I'd like to get an idea of what sort of
broadcast traffic I might be seeing on the port...