Stephane M wrote:
> Hi,
>
> I've got a Modem Router, which supports QoS service
>
> I gave high priority to my SIP protocol....
> But I still have some troubles, when I am on the phone and I am sending
> an email (for instance)
>
> I have the same problem at work, where I am using a Netgear FVX538.
>
> To give an example, at home I am using 'Billion BiPAC 7300G'
>


> On the QOS part,
> LAN -> WAN
> Packet Type : ANY (tried as well with TCP only)

SIP and RTP (the audio) tend to use RTP.

If you are using packet type any, then it is unlikely to succeed because
some types of packet don't have port numbers. You can only match them
by IP address.

> Local Application ports : 5000 - 5100
> Remote Application ports : 5000 - 5100

You need to see what port numbers your phones are using for RTP. They
may be different with each call. Inbound audio may well use different
port numbers to outbound.


> And when I am sending some email, I can hear the person correctly, but
> he cannot understand me correctly while sending information ... :-(

In a SIP phone call, the 2 audio streams are largely independent of each
other.

If you try to send more data out than your outbound connection can cope
with, then the buffer in the router will fill. When the buffer fills,
packets are lost and you lose voice quality.

When a router is giving priority to a certain type of packets, then it
will drop other kinds of packets first. Or on a really good router, it
will send back ECN (explicit congestion notification) packets to try and
get the sender to slow down.

In my experience, I've never found the Qos features of consumer grade
routers to be much good. And in some cases they cause more harm than good.

In other cases, people try to buy a qos router to solve some other
problem which is giving poor call quality. A router that can give
priority will not magically fix a bad connection.

A CTX1000 is the best prioritisation device I know of at the moment.

Tim