Nexus 7000 Packet Fragmentation to lower MTU

[borman.bravo]

I understand the Nexus 7000 does not perform packet fragmentation per design. I have a L2 VPLS circuit providing L2 VLAN extension between Data Center A &B coming in directly into an interface in a Nexus 7009 that restrict packets size to 1460, is there a way to circumvent this limitation and change MTU or adjust the TCP segment size etc. in the Nexus 7Ks? The carrier will not change their MTU to anything higher than 1460.

I appreciate the feedback!

[HelenaC]

Hello, 

You can verify MTU fragmentation for packets that exceed the configured mtu with the command "sh ip traffic". This works even for pings sourced from the interface. The counter "fragments created" should increment:

Fragmentation/reassembly:
Fragments received: 2003, fragments sent: 2554, fragments created: 2554,
Fragments dropped: 0, packets with DF: 672, packets reassembled: 973,
Fragments timed out: 57

In your case I suppose you have to set the interface mtu to 1460. The drawback is that packet fragmentation is cpu intesive and under heavy traffic it can affect the swicth performance.