L3 Roaming and MTU

[AxL1971]

From my understanding in a L3 Roaming setup, a tunnel is created between the AP's to support this feature

My question is does this reduce the MTU of the packet.

[ConnorL]

The maximum MTU for Layer 3 roaming SSID is 1448. You can verify this by using setting the packet size of a ping and reducing the payload size before fragmentation.

I should stress that in most topologies, Layer 3 Roaming isn't actually required, it's mostly for large campus topologies where seamless roaming across VLANs is needed. So before using this feature, ensure you review the linked KB to validate this is a requirement of your design.

[AxL1971]

from this the MSS would be 1408 (40 bytes for IP header + TCP header)

[AxL1971]

we use this feature due to have multiple VLAN's across a large site and users roaming between access points and require connection to remain established when roaming between multiple VLAN's and IP address changing.

[ChrisJ2]

 If you do require L3 roaming, and this is an issue, you can use DHCP option 26 to set the clients to a smaller MTU size.