Re: Problem to priorize SSH traffic

Ludovic Leroy wrote:
> Andy,
>
> ip + 14? How do you get this result?

It's IP + src/dst MAC + ethertype protocol (which you can match with tc
filters using a negative offset)

On a vlan interface it's it's + 18

On ppp it's just IP length.

If you make a filter/class for say icmp and play with ping you can
infer the overhead by looking at the byte counters.

This is nothing to do with stab - it's always the case, so you need
to take it into account when working out what number to use for overhead.

My old DSL link was pppoa vc mux so the fixed overhead was ip + 10.

When I has a PCI modem and shaped on ppp0 the overhead param of stab
was 10.

When I later got a stand alone modem connected by eth I had to use -4
as the overhead to allow for the fact that tc already saw ip + 14.