[Asterisk-Users] 128 kbs satelite link

[Steven Critchfield]

On Wed, 2003-12-17 at 08:48, Senad Jordanovic wrote:
> Hi all,
> 
> Anyone has experience  using * through
> 128 kbs (or bigger) satelite link?
> 
> In particular I am interested to hear how many calls could be put
> through 128Kbs satelite link simultaneously?

128k may seem like the bottleneck, but it may not be the true limiting
factor for you. Ping some machine near or for sure the machine you will
be calling and see what kind of delay you will be dealing with on top of
the packetizing of the audio. Basically add at least 20ms to the ping
time to get an idea of the base line lag you will have.

To give you an idea, my 14 hop trip to the gateway I was using is
between 55-77ms on ping time, add the 20 ms packet size and your get
75-97ms base line lag. If you are using a jitter buffer, that adds a
little more to the time so that it can deal with drop packets.

I think I heard that satalite first hops are usually in the 400ms range.
Are you prepared for half second or more delays?

As far as call numbers, 1 for sure any codec if the only part that is a
bottleneck is your link. 2 calls with occasional drop outs with almost
any codec but ulaw or alaw. 3 calls will be pushing it with just about
any codec. I could occasionally handle 3 calls with GSM on my 256k cable
modem before call quality was significantly impaired.  
-- 
Steven Critchfield <critch at basesys.com>