[Asterisk-Users] Hardware vs. Network Inputs

[Michael Stearne]

Chris... thanks for the great reply....
On 10/5/05, Chris Shaw <chriss at precisionpump.net> wrote:
> Michael,
>
> Doing an All-Network setup is completely doable but there are many factors
> to consider.
>
> First of all, I didn't see any mention of how many connections it takes
> before Asterisk starts having difficulty with DTMF.

When we have problems and we are testing, there are no other calls. 
So the problem happens with just 1 connection.

You mentioned that the
> computer is directly connected to a T1, is it the only computer using the T1
> or are there others?

It is shared but most of the time (even at night with little traffic)
there is at least 900Kb available.

>
> Also what kind of network is it?

The machine is connected via a switch directly to the T1's modem (i am
not sure what exactly it is)

> Do you have a good SLA?

Whatever is standard from Verizon.

What kind of packet
> loss do you experience on average?

In general from our network, none.

What is your ping time to the Broadvoice
> proxy that you're using? Are you using any kind of QoS?

We are not using any QoS.  Is there anything we can do on our side to
ensure the best performance for that machine?  A traffic shaper or
something?  The pings to BroadVoice go from South Jersey to NTC and
are usually in the 23ms range (the same as they are to Yahoo).

>
> Remember that Broadvoice only uses G.711u/a so with RTP + UDP + IP overhead
> you're looking at ~85kbit/s so at around 9-10 concurrent calls you're going
> to be pushing it a bit with 900Kbit available bandwidth.

Thanks for that tip.  Right now we dont' expect more than a couple
concurrent calls but we will watch that.

>
> You might try turning the SIP RelaxDTMF setting on, that may help,

Did that with no noticable difference.

also if
> you don't have and are not planning on getting any Zaptel hardware, consider
> using Ztdummy or ZapRTC as an RTP timing source. I know that on the wiki it
> says that they are really only useful for MoH or MeetME but I've found it to
> help greatly with audio quality and Asterisk's DTMF detection. YMMV.
>

I will definately look into that.

We also have a call into BroadVoice and they are "looking into it" but
they don't have any account types that give more bandwidth or QoS so
it doesn't look like we can get direct help from them.

We also have a VoicePulse account and both incoming accounts never
really act up at the same time.  Meaning when BV is doing poorly VP
could be doing fine.  That's  why we don't think it's our network.

Thanks,
Michael