SUGGESTIONS Codec configuration - quality/reliability

[pacpac]

Hi, I am using PBX in a Flash 2.0.6.6, Asterisk 1.8.23.0 and FreePBX 2.11.0.10.

I am located in the Americas connecting to my server in the US using a Yealink T46G. My DID originates in the UK. Termination provider is in the US. All parties support G711 alaw, ulaw and G729.

I am making 50/50 outbound calls to US and Europe numbers.

With respect to codec, what would be the best configuration (media goes through Asterisk and all calls are recorded) to ensure best call quality and reliability?

1) Only use G711 alaw
2) Only use G711 ulaw
3) Use both G711 alwa and ulaw
4) Only G729

Thanks.

 

[jmcman]

Assuming you have decent bandwidth, I'd just stick with ulaw...

 

[pacpac]

Thanks, a specific reason for why choose ulaw and not alaw?

 

[jmcman]

I vote ulaw since it's the de-facto standard across the board these days with both providers, endpoints and everything in between. Previously, alaw used to be primarily destined for European use and ulaw was for North America. These days it doesn't matter...

 

[pacpac]

Noted, thanks. For some reason I get less latency when having configured only one codec all the way through. Any idea for why this is?

 

[jmcman]

Noted, thanks. For some reason I get less latency when having configured only one codec all the way through. Any idea for why this is?

Not sure, but then again I am definitely no expert. Maybe someone else can chime in on that.

 

[pacpac]

My T46G supports G722 and so do Asterisk. Would it be an optimal (and is it possible?) configuration to do G722 to/from Asterisk and the T46G and G711u out from Asterisk to the termination point and G711u from DID provider into Asterisk?

 

[jmcman]

I don't think it's optimal, IMHO. I'd just keep it ulaw the entire way for simplicity. If there are any problems internally with asterisk transcoding the session, it may be more difficult to troubleshoot.