[asterisk-users] Asterisk and 802.11g

[Yuan LIU]

>>From: Jason Fuermann <jbf005 at shsu.edu>
>>Date: Thu, 08 Feb 2007 10:33:26 -0600
>>
>>your asterisk box has to do audio conversion, its getting bogged down

I realize that I forgot to give some important details.  Actually the VoIP 
caller in question is from another Asterisk sitting on the same LAN but on 
Ethernet.  Additionally, calls from a SIP hard phone (GrandStream, pictured 
as VoIP extension in the original drawing from same LAN) directly to the 
Wi-Fi Asterisk into PSTN have not caused any network blockage.  So the 
complete scenarios are like this:

1. <--- FXS-Asterisk-Asterisk-FXO,

caller
   |_ FXS _ *A --- 802.11g --- *B
                                        |
                                      FXO ___ PSTN ___ recepient

---> bad, causing Wi-Fi blockage

2. <--- FXS-Asterisk-Asterisk-Console,

caller
   |_ FXS _ *A --- 802.11g --- *B
                                        |
                                   Console ___ recepient

---> acceptable, no Wi-Fi congestion

3. <--- GrandStream-Asterisk-PSTN,

caller
   |_ GrandStream --- 802.11g --- *B
                                         |
                                       FXO ___ PSTN ___ recepient

---> acceptable, no Wi-Fi congestion

Each scenario engages the same Wi-Fi network to the same Asterisk box (*B).  
The network blockage only occurs when two Asterisk boxes are involved. 
(Senario 1)

Any idea? (There's little extra traffic in Wi-Fi, nor is there any other 
active channel in any Asterisk.)

Yuan Liu

>Thanks for your reply, Jason.  Two further questions:
>1) I thought all networking would be done in the card, not taxing CPU much?
>2) I get reasonable quality (and no significant network blockage) when I 
>answer call from Console.  In this case, Asterisk also needs to "transcode" 
>audio into the sound card, right?  G.711 is supposed to be the least taxing 
>CODEC, and I'm pretty sure I'm using G.711 between VoIP extensions (hence 
>no transcoding between VoIP and FXO. (disallow => all, allow = ulaw)
>
>Yuan Liu
>
>>Yuan LIU wrote:
>>>I'm greatly surprised when testing an Asterisk box with 802.11g.  Here's 
>>>the topology:
>>>
>>>VoIP caller --- 802.11g --- Asterisk --- 802.11g --- VoIP extension
>>>                                       |
>>>                                     FXO ___ PSTN extension
>>>
>>>When I call a VoIP extension on that box (from a VoIP extension), voice 
>>>is good.  But when this box tries to bridge the call with a PSTN 
>>>extension, voice is completely broken.  And it's not because of the cheap 
>>>X100P - when I ping the box, round trip is >4,000 ms, most of the time 
>>>causing timeout.  Once the call hangs up, ping time dropped to 1-2 ms.  
>>>Ping time started to surge even when FXO is simply ringing.
>>>
>>>If VoIP to VoIP extension call uses re-invite (which it did), voice is 
>>>also good in the Console channel.
>>>
>>>How can voice traffic stall 802.11g? (I haven't checked, but CODEC is 
>>>likely ulaw.)