26.1.4 VXLAN packet-length

When encapsulated in VXLAN tunnels, it appends the highest 54byte of headers. As a consequence, if the size of VXLAN encapsulated packet is larger than VXLAN Network port-side MTU, or if the size of VXLAN encapsulated packet is larger than MTU setting by VXLAN PMTU facility, the applicable frame is discarded without fragmenting it. Also, if a VXLAN encapsulated packet is fragmented within a Layer 3 network, it will not work properly.

To prevent MTU overflow or fragmentation, one of the following settings is required:

• Set the port MTU of VXLAN Network port to a value equal to or greater than the port MTU of VXLAN Access port to which 54byte is added.

• You can use VXLAN PMTU feature to eliminate the need for VXLAN Network port-side MTU settings. For more information, see 26.1.12 VXLAN PMTU Features.

• Set MTU size of the sender so that a VXLAN overflow does not occur.

• For TCP communication, reduce the packet-size by rewriting MSS(Maximum Segment Size option in TCP header. For example, a router on the communication path.