[LARTC] Shaping incoming VoIP traffic fails

[Larry Brigman]

On 11/15/06, Daniel Musketa <Daniel at musketa.de> wrote:
> On Wednesday 15 November 2006 12:07, Daniel Musketa wrote:
> > Could I setup HTB better than below? Should I reduce eth1's queue length
> > (now 1000)? If yes, how?
>
> The txqueuelen can be changed by
>
>     ip link set eth1 txqlen <len>
>
> I tried values of 100 and 3 but can't hear an improvement.
>
> I can watch traffic coming in on ppp0 with `iftop` and it never exeeds
> 900kbit. Why could a 2000kbit headroom be not enough for clean receiving of
> 80kbit VoIP data?

Because you are not on the controlling side.  The router upstream of
you doesn't have
the concept of priority of the voip traffic so what comes first, goes out first.
Also if the download side can send at a higher rate than you line can
handle, there
will be a queue of packets at  the router handling the bandwidth limititation.