Gigabit port drop packets

[dtapia]

Hi,
I have a WS-X6724-SFP module,  and  a gigabit port  start  to drops packets  each time the traffic reaches a bandwidth between 700 and 800
M.
This symptom occurs on multiple devices 7600 that using the same version of IOS:

c7600s72033-advipservicesk9-mz.122-33.SRB4.bin

[donprapop]

Hi

         pls show log

Thanks

^,^

[Souvik Ghosh]

please attach the output of show tech command from the router.

rgds,

Souvik

[Mahesh Gohil]

Hello,

Putting just show version will not help people to rectify the issue.

Need more details like

> running config of gig interface

> Any policy-map config called on this interface

> Output of show interface

> show pilicy-map int

Regards

Mahesh

[dtapia]

There are not  policy-map config on this interface.

I hope that this information help you.

Thanks

[Mahesh Gohil]

Hello,

By looking at explanation given in below doc for overhead it looks normal to have some

drops but I haven't tested anytime as what is the maximum supported throughput from end user

perspective.

http://www.tamos.net/~rhay/wp/overhead/overhead.htm

Please go through above link.

Regards

Mahesh

[Souvik Ghosh]

Hi,

Sorry for the super late reply.

here are few of my questions and observations.

There is only one link which is up ..2/3 ... what is the egress interface for the 700 Mb traffic ? since only one link is up are all the traffic terminating on this router ?

if all the traffic is terminating on this router then the traffic needs to be processed by the cpu. now if the cpu is too much overloaded then it is expected to see packet drops.

i do see some evidences of the packets going upto the CPU. for the interface gi2/3 there  are lot of input queue drops. INput queue is the path taken by the packets which are going to the CPU and wait in the queue before they are processed by the CPU.  Also if i see the show proc cpu history output i can see that the average cpu utilization for last 72 hours is around 40/50% this is on the higher side considering 6500/7600 being a hardware switched platform.

There are also few input errors mainly because of CRC under the interface however that might not be related to the traffic.

Please clear the counters for the interface gi2/3 adn observe the show interface output. Check if the input queue drops are incrementing or not when the traffic is going around 700/800 Mbps.

Regards