[c-nsp] setting max mtu on switch (Jumbo)

[Reuben Farrelly]

On 29/05/2012 6:09 PM, Gert Doering wrote:
>> Is it best practice to set all switches to max mtu?
>
> "Big enough to achieve what you need to achieve".  If all your L3 devices
> only use 1500 bps MTU, and no EoMPLS tunneling or whatnot, there is no
> real benefit in upping the switch MTU.  There does not seem to be a
> downside either, though.
>
> gert

I've often wondered about supposed downsides myself.  Why is it that we 
don't see the layer 2 MTU set as high as possible on Cisco devices out 
of the box, but a relatively "normal" routing MTU set to 1500 in the 
default config?   Are there any "bad things" that could come out of this 
config?

Some of the HP (Flex 10 etc) switches we run here do jumbos by default 
and I don't think there is any way to lower it. Then again these are 
storage switches so....

Reuben