>with more than 15 voip phones working at the same time I get some echo
>and buzzing sounds when shaping is turned on. Any ideas as to why echo
>happens in voip networks?
>I have 1 queue setup for all voip traffic and this has priority 90.
>All other trafic is in another queue with priority 10.
>Would increasing memory (I have 128MB) help? Any other suggestions?
Normally echo is one of the symptoms of too little bandwidth. Assuming
you don't have it without shaping turned on, I'd guess that you'll also
see it even without shaping if you increase the number of active
phones. What kind of connection are you on? You may be nearing
saturation of you're outbound connection. The 10% you're removing to
deal with shaping could be pushing you over the limit.