Cisco Nexus 6004 switch drops IP packets greater than 300 bytes

[msrohman]

Hello all,

We have a Level 3 10G wave circuit running in between two Cisco Nexus 6004 switches. The circuit came online between our two data-centers (in the same city) without a problem.

When we attempt to ping the remote-end's 10G interface, it works fine with 64byte packets. CDP is enabled and we can view the remote switch CDP information. However, if we increase the size of the ping packets to upwards of 300 bytes, we lose 1 in every 20.

We verifed MTU settings, 10G cable type, and duplex settings. 

Level 3 has tested clean and we are going forward with more tests.

Any ideas as to the problem? We are having the carrier come out and test end-to-end with their testers. But so far, the circuit is testing clean. I wasn't sure if this is something Cisco related. I'm at a loss at the moment.

Thanks.

Mike

[Reza Sharifi · Accepted solution]

Hi Mike,

There is nothing wrong with your switches or the circuit.  Nexus devices have a default COPP policy on the control plane that limit the size and the amount of traffic that needs to be  process by CPU.

http://www.cisco.com/en/US/docs/switches/datacenter/sw/6_x/nx-os/security/configuration/guide/b_Cisco_Nexus_7000_NX-OS_Security_Configuration_Guide__Release_6.x_chapter_011001.html

HTH

[msrohman]

Spot on, Reza. That was it! We ran a bunch of ICMP tests with a packet capture. The circuit is not dropping packets. Nor is the switch. It had do with the control plane.

This solved the problem. Thanks a lot for your post!

Mike

[Reza Sharifi]

Glad to help Mike

Thanks for the rating