Upgrade to 22.1.3 and above will enable the LRO knob resulting in VS traffic disruption.

Products

• VMware

Issue/Introduction

Symptoms:

• Auto enable of LRO post upgrade may cause Performance/packet loss issues.
• This issue may occur at L2 segment or in environments with IP routing enabled.
• Bigger packets will be seen on SE capture if LRO knob is enabled on Service engine group.This will eventually cause ICMP Fragmentation Needed error.(as DF bit is set)

Cause

• Starting with NSX Advanced Load Balancer 22.1.3 version, LRO is enabled on serviceenginegroup by default for supported environments, such as, Vmware/ NSX-T Cloud.
• LRO is a NIC offload technique which coalesces incoming packets to deliver larger packets to the stack. LRO when enabled on SE interface usually coalesces incoming packets to send a large packet, if the outgoing stack doesn't support this large packet due to limitation on MTU, an ICMP fragmentation needed error occurs.

Resolution

• The following are the CLI commands to determine if LRO is enabled at the Service Engine and the Service Engine Group level -

• [admin:<Ctrl IP>]: > show serviceengine <se-name> interface | grep lro
  | lro_on                                  | True
  
  [admin:<Ctrl IP>]: > show serviceenginegroup <seg-name> | grep lro
  | se_lro                                  | True

• We need to disable LRO at the SE group level. The following is the CLI to disable LRO on the SE Group level: 

  [admin:<Ctrl IP>]: > configure serviceenginegroup Default-Group
  [admin:<Ctrl IP>]: serviceenginegroup> no se_lro
  [admin:<Ctrl IP>]: serviceenginegroup> save

• The service engines have to be rebooted for this configuration to take effect.
• Refer to the configuration guide for more information - https://avinetworks.com/docs/22.1/configuration-guide-tso-lro-gro-rss/#in-nsx-advanced-load-balancer 

Workaround:
Not available