[TriLUG] DirecPC and VoIP (Kinda OT)

[Aaron Caudle]

Thanks for so much information guys.  I really appreciate it.  This 
problem has been hanging over my head for months now and I just want to 
get it resolved.
I am currently inquiring with the installers in Haiti on the issue too.  
BTW - they recommended Vonage.
Since the phone connects to our office here in Asheville, I think I have 
control over the codecs, but if it is G.711 then I know we don't have 
that type of bandwidth.  We are using an Altigen PBX and we can actually 
see the phone connect, reports its IP etc.  However, when dialing the 
extension we just get a line is busy error.
One of my fellow employees (who is responsible for the phone server) 
contacted Altigen and they said that the latency might be the issue in 
that the server might time out when trying to establish communication 
with the phone.  Although I don't understand it completely, that 
scenario seems likely.
I sent a Smoothwall down there, in hopes of being able to have some 
degree of control over the issues and configuration.  We tried yesterday 
and for some reason I wasn't even able to connect to it.  Now, I realize 
that I can't avoid that satellites NAT and that by using the smoothwall 
I am just adding another layer of NATing.  (IM and language barriers 
make troubleshooting very difficult and time consuming.)
I'm pretty sure that they aren't getting close to their transfer cap 
because the power is very sporadic.  Most of the time all the equipment 
and network is running off some generators and this is only for a few 
hours a day.
Once again, I really appreciate everyones help, keep the suggestions coming!
Sincerely,
Aaron Caudle
speedsin.net

>Brian McCullough wrote:
>> 
>> | I have recently been noticing some port blockages that I haven't in the
>> | past, including those related to VOIP.
>> |
>> 
>> Speaking of VOIP, how much bandwidth/bytes per second/whatever do a
>> typical VOIP connection use?  DirecPC had an acceptable use policy that
>> knocks you down to 56k if you transfer too much data within 'X' amount
>> of time.  When I called them to get specifics, they flat out refused to
>> tell me exactly how the system decides when to shut you down.  In my own
>> tests, I could not download a file larger than about 70-90mb, and I'd
>> have to wait a few hours before downloading something else, or my
>> connection would drop to 56k for about a day and a half.
>> 
>> I wonder if your VOIP connections are over-utilizing your satellite and
>> forcing the system to cut your bandwidth?
>  
>
>
>The poorest modern implementation (using G.711, the poorest codec)
>averages about 40k for a conversation.
>
>If they use a nice codec like G.729 then the average for a conversation
>drops to 8k. Of course that codec is tuned to typical voice frequencies
>and has problems with DTMF so it's hit/miss when trying to code in
>numbers via a phone call.
>
>Jon
>