asked on

What Lync use, µ-law or a-law

Dear All,

I'm working to integrate our Lync 2013 environment with Cisco call manager environment for Enterprise Voice, i need to ask what Lync use with G.711, is it µ-law or a-law?

I can't found a link from Microsoft to show the clear answer :(

Jon Doe

Ulaw is the mode used in the US while alaw in the UKs and Australia. You may want to check with your telephony provider the version they provide. Lync 2013 mediation service supports both.

Rhala

ASKER

Dear Sunit,

I didn't asked for that !

i'm asking about what Lync support and work ...

Jon Doe

What kind of support are you talking about ? Lync clients will obviously support what the mediation server supports. Peer to peer calls use proprietary RTAudio. Lync client calls originate through RTAudio and get transcoded to G711 via the Lync mediation service. External voice calls through the mediation server using SIP, IP/PBX and ITSP use G711 and is fully supported by the Lync client. If you choose media bypass, the Lync client will communicate with the SBC or voice gateway without RTAudio, straight G711, not using the Lync mediation server which is a better option for enterprise voice deployments for latency, jitter and packet loss avoidance. Either way, Lync will work with ulaw or alaw. In your part of the world and pretty much the rest, its alaw, the US and Japan use ulaw.

Rhala

ASKER

Dear Sunit,

All what you mentioned is right and i know it, but it's not what i'm asking about ...

G.711 defines two main companding algorithms, the µ-law algorithm and A-law algorithm. I'm asking what exactly Lync 2013 client and server use, it's µ-law or A-law??

For example, Cisco Call Manager used G.711 A-Law in the communication

Jon Doe

Again. Ulaw and Alaw are both supported by LYNC 2013. Your PSTN provider decides the companding algorithm. In your country, its Alaw. CUCM can be configured to use either ulaw or alaw for PCM.

Rhala

ASKER

Dear Sunit,

Forget the PSTN please, i'm connecting to Cisco call manager as i mentioned above, and i need to know which algorithm is work in Lync? if Lync support both, could you please provide me a link from Microsoft saying that?

Jon Doe

No link from technet but here you go. Read the part in the image where the PCMu and PCMa are mentioned in the Lync 2013 client logs for a completed call.

Jon Doe

Lync 2013 codec support

Rhala

ASKER

I've requested that this question be deleted for the following reason:

no answer !

Rhala

ASKER

not an answer at all, i been looking for something and the answer is something else, so what mentioned is not an answer ...

Rhala

ASKER

I've requested that this question be deleted for the following reason:

what mentioned is not considered an answer

Jon Doe

ulaw and alaw are both supported by LYNC. The connectivity depends on the mode set in the CUCM, the client and server can do both. If it is set for Alaw, the client will use it, if ulaw, Lync will communicate with that too. If you buy my ticket, I will run wireshark and prove it to you :)

ASKER CERTIFIED SOLUTION

Rhala

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

Jon Doe

You were just looking for a link ? The technet article supports and confirms my answer. Thank you.

Rhala

ASKER

It's the link which i was looking for and i found it with Mr. Wolfe help.

Jon Doe

Your question did not specify that you needed simply a link for an answer. It said you cannot find a link. Since my answer stated Lync 2013 supports both companding algorithms, it is the correct answer and needs to be deemed the accepted solution. Thanks.