[asterisk-users] What are the reasons for VoIP echo?

[Martin]

if a user calling you hears echo of himself then it's the fault of
your sip device/sip phone.
The manufacturer must be using a cheap or an open source echo canceller ...

try getting a different sip device made by some 'normal' company like
polycom or linksys/cisco

Martin

On Thu, Oct 1, 2009 at 9:10 AM, Myles Wakeham <myles at techsol.org> wrote:
> I have an Asterisk 1.4.2 system that has been installed for about 3
> months now in our home.  We converted all of our phones to SIP phones,
> and use two different trunk providers (BroadVoice for incoming &
> FlowRoute for outgoing).
>
> Most of the time its working flawlessly.  But about 1/3rd of the calls
> that come into us complain of an echo and what is best described as
> latency issues.  Its not consistent though.  I was on the phone with an
> insurance company yesterday for about 1 hour and the call was perfect (I
> originated the call which used Flowroute for the SIP provider).
>
> What seems to be a pattern here is cell phones.  When we receive a call
> from a cell phone, or from certain people on certain phone systems, they
> consistently complain of echo in the call.  Its far less regular when we
> originate the call, which suggested to me that the problem might be with
> Broadvoice.  But I'm now hearing that us calling back the party doesn't
> always solve the problem either.
>
> We upgraded our Internet feed (we're on a cable Internet through our
> cable company, with 12mb/s down, 1.5mb/s up) and that seems to have
> helped but not solved this problem.  From what I can see, its some form
> of latency issue.  We use IPCop as a firewall for our Internet access,
> but have turned off any IDS on it so that its running fast.  I can play
> online computer games through the network with no issues at all, so I
> don't think its slowing down the traffic and if it was I'd expect this
> problem to be occurring consistently on all calls.
>
> Are there any tweaks that I can do with Asterisk to increase the network
> performance to reduce these issues?  Have others who have experienced
> this been able to identify the issues to external VoIP SIP providers
> only, or does our system have something to do with all of this?  At the
> time of the calls coming in, IPCop is telling me that we don't have more
> than 100K/s of bandwidth in use, and according to the network bandwidth
> graphs there, even with 2 people on the phone at the same time, the
> bandwidth never seems to exceed 300K/s, so I think we have plenty of
> headroom for this.  I checked with our cable provider for issues with
> modem latency, and they couldn't detect anything.  Again, I'm not
> experiencing any lag issues with computer games, particularly those that
> are heavy in interactivity, so I don't think that is the reason.
>
> Any suggestions as to what could be tweaked would be greatly appreciated.
>
> Myles
> --
> =======================
> Myles Wakeham
> Director of Engineering
> Tech Solutions USA, Inc.
> Scottsdale, Arizona  USA
> http://www.techsolusa.com
> Phone +1-480-451-7440
>
>
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