[asterisk-users] Re: Help - Poor Voice Quality

[Stephen Bosch]

Ed W wrote:
> Hi
> 
>> Yes, I know that I am using IAX2 and not SIP for my connection to
>> teliax.  IAX2 is the preferred protocol for connection to teliax.  I
>> have the firewall configured to prioritorize port 4569 for IAX2.
> 
> 
> 1) 4569 is only the IAX setup port.  Edit rtp.conf to limit the rtp
> ports to some subset and then prioritise those instead
> 2) Uplink bandwidth is always the constraint on these lines.  This is
> highlighted in this case
> 3) Shorewall can't correctly prioritise bandwidth whenever using some
> kind of DSL service or whenever the packets are encapsulated such as the
> cable service.  Read the linux QOS faq for more info and as a workaround
> slash the theoretical bandwidth in half in your shaping script.  This
> should get you working and you can tweak later
> 4) Monitor the QOS buckets as you make/break calls to check that all the
> packets are classified correctly.  Otherwise your voip packets might be
> accidently in the bulk box

QoS is a wasted effort on a simple home setup. It usually makes things
worse rather than better.

Have you considered running OpenBSD with pf over Shorewall?

-Stephen-