RE: Question regarding protocol specific mtu for FCoE

Zou, Yi
2009-06-03T22:25:38Z

> > So FCoE cannot say "fcoe_mtu = min(OPTIMAL_FCOEMTU,netdev->mtu)" and
> > send-down frames based on that?
>
>I think the point is that FCoE wants to use OPTIMAL_FCOEMTU (2KB + a
>bit
>for headers) even when netdev->mtu is 1500. (eg datacenter network
>supports baby jumbo frames so FCoE traffic that stays within the
>network
>should use OPTIMAL_FCOEMTU, while lots of IP traffic is going out onto
>a
>1500-byte MTU campus and having TCP doing lots of PMTU discovery is a
>pain)
>
> - R.

Yes, exactly, thanks for the clarification. Also, since FC max payload
of 2112 is not going to change, I guess the OPTIMAL_FCOEMTU is probably
going to stay unchanged forever.

Thanks.

yi