Fragmentation of jumbo frames with MTU greater than 1500 from Gigamon vSERIES VM is observed

Products

• VMware NSX

Issue/Introduction

Sending any traffic from guest VM Gigamon vSERIES with size greater than MTU=1500 results in fragmentation. Thus, unable to forward jumbo packets from VMWARE to probes

Environment

3.2.3

Cause

• Ping with jumbo frames to the default gateway is working OK without fragmentation, but it is not working for the remote tunnel interface from Gigamon vSeries VM.
• But vmkping (below command) from TEP interface of the ESXi  with jumbo frames towards both default gateway and remote tunnel interface is working OK without fragmentation 

vmkping -I vmk10 -S vxlan -s <jumbo packet length> <dest IP> 

• Also ping traffic with MTU > 1500 from another RedHat VM connected to same segment as Gigamon vSeries is able to reach remote tunnel interface without fragmentation. As E2E path is working OK, there are no issues observed with VMware infrastructure

 

Resolution

Troubleshoot with Gigamon vSeries team for this specific use case of reaching external interface via tunnel GW on vSeries VM with jumbo frames