Symptom

C8500L router can experience overruns with flow control enabled Router#sh int te0/1/0 | inc over 3729359117 input errors, 2 CRC, 0 frame, 3729359115 overrun, 0 ignored Router#sh int te0/1/0 | inc flow output flow-control is on, input flow-control is on

Conditions

This issue is specific to C8500L-8S4X. Heavy traffic load, exhausting the routers packet rx or processing capabilities. This happens especially with small (64 byte) sized packets at high rates on 10g interfaces.

Workaround

Flow control can be disabled for more predictable behavior with Router#conf t Router(config)#int te0/1/1 Router(config-if)#no plim qos input queue 0 pause enable Router(config-if)#no plim qos input queue strict-priority pause enable but there is no workaround to get flow control to work

Further Problem Description