[c-nsp] 3750, QinQ & Jumbo Frames?

[Nathan]

On Wed, Oct 15, 2008 at 3:34 PM, Howard Jones <howie at thingy.com> wrote:
> "*Note: *If Gigabit Ethernet interfaces are configured to accept frames
> greater than the 10/100 interfaces, jumbo frames that ingress on a
> Gigabit Ethernet interface and egress on a 10/100 interface are dropped."

Well, yes, they have to be.

You have two kinds of packets called "jumbo", the FE kind of jumbo
configured with "system mtu XXXX" which can have limits like 1546 or
1998 or 2018 and probably lots more, depending on how far the hardware
designer stretched the FE specs, and GE jumbo which is mostly 9000 and
is configured with "system mtu jumbo XXXX" but only works on gigabit
interfaces.

I believe your switches have an FE maximum MTU of 1998, so if you are
just making room for some QinQ headers on a 1500-byte packet then you
have nothing to worry about :-)

-- 
HTH,
Nathan