Error: "VLAN subinterfaces limited to 6000 MTU"

Products

• VMware Telco Cloud Automation

Issue/Introduction

• When creating VLAN subinterfaces for a node pool in TCA via a node pool policy, the max MTU allowed is 6000.
• The MTU limit should be higher since all distributed switches and segments in the infrastructure are set to 9000 MTU.

 

Environment

3.2

Cause

• The default behaviour of VLAN sub-interfaces with the use of 802.1Q tagging, which adds 4 bytes to the Ethernet frame.
• If additional encapsulations like Q-in-Q (Double VLAN Tagging) or MPLS are used, even more overhead is added.
• Keeping the MTU below 6000 helps prevent fragmentation when the frame traverses different network segments. 

 

 

Resolution

Resolved in TCA 3.2.24441748