Nexus 5K MTU issue

[courageux]

Hello,

We are experiencing a MTU issue in our Nexus environment. 2 7K and 2 5K. 2 2248s off of 5k. There is a server connected to a 2248 in vlan A and sanitber server in vlan B on 5548. 5548s are configured with system qos policy map to set the MTU to be 9216. 7ks are also configured with system jumbo MTU command. However, large size packets are not getting through from vlan A to vlan B. Ping test with large packets from 7k, sourced from either vlan fails as well.

Any help would be appreciated.

Thanks.

[CHAD SIMMONS]

Did you set the MTU on the L3 interfaces on your 7K as well?

[Ruhann Du Plessis]

What is the Max MTU you can succesfully pass?

If you configured the "system jumbomtu" on the N7K and a "network-qos" service-policy on your N5K, then you should confirm the MTU 9216 is manually set on all transit N7K interfaces, and on any relevant VLAN interfaces if any.

On the N5K use the command : "show queueing int eX/X" and look at the QOS group 0 output. It should like :

   "q-size: 243200, HW MTU: 9280 (9216 configured) ". QOS group 1 is for FCOE. Safe to ignore for your question.

On the N7K transit interfaces, the "show int". should show the correct MTU.

Hth