L2vpn MTU Question

[jwinegar]

I have a L2vpn xconnect between 2 ASR9k's (MPLS).    Both AC sub-interfaces have an mtu size of 1518.

This circuit is created for AT&T which the SLA requires RFC 2544 Max MTU sizing of 2000.  

The 2544 test passed packets of MTU 2000 without having to change AC's mtu size from 1518.    I

was asked how is this possible and I don't have the answer.    The Core facing interfaces are MTU 9202.

Could anybody elaborate ?

[nsalgado]

Hi,

This is expected, as in L2vpn subinterfaces the MTU is not enforced, but just used for signaling.

More details in the thread below.

https://supportforums.cisco.com/t5/xr-os-and-platforms/jumbo-frame-support-under-l2vpn-sub-interface-on-asr9k/td-p/2390760

Hope if helps.

BR,

Norberto

[jwinegar]

Thanks for the info nsalgado.