DSPFARM- transcoding and conferencing

[kitog]

i'm a bit confuse with the number of sessions per dsp.

Lets say i have centrelized CCM and DSPFARM and 2 gw to PSTN one for each site.

1. when remote 7960 calling local 7960 , each phone is using different region so the call is g729, as far as i understand the phone are using internal DSP so they are not using the DSPFARM, correct?

2. when calling from PSTN on the remote site to 7960 on central site, the call suppose to be g729, so the DSPFARM is being used, true? in this case does it mean it is one session for the DSPFARM? (configuring: dspfarm transcoder maximum sessions ...), or does it mean two sessions?

3. on a conference call with 6 participants, how many sessions there are? so, when configuring: dspfarm confbridge maximum sessions 10 - does it mean i can setup 10 conference call 6 participants each?

Thanks you all, Kito.

[paul.harrison]

Kito,

1. Correct both phones are capable of running G.729 and do so directly, no need for the DSP farm at this point.

2. No. Cisco Gateways support G.729 and so can pass the stream as a G.729 call to a 7960 without the use of a DSP farm, correct call manager configuration dictates the codec but Cisco routers can make the calls without a problem.

3. No. The maximum sessions dictates how many callers the conference bridge can handle in total. So 10 sessions allows 1 x 6 party and 1 x 4 party but that's it, or 2 x 3 party and 1 x 4 party. As long as the total number does not exceed the conference bridge sessions.

Paul

[mowour]

Hi Kito,

1. When calling from an IP phone at the central site using G711 to an IP phone at the remote and G729 is used on the Wan, internal DSPs on the phones are used, so those on the DSPFarm are not used. The phones should be able to handle the disparate codecs.

2. When calling from PSTN on the remote site to a 7960 on central site, and G729 is used on the WAN, you're not using the DSP Farm. DSP Farm is a term used to distinguish the DSP resources that are dedicated to conferencing and transcoding from those that are used for voice termination. In this particular case, a DSP is used, but only for voice termination. The DSP Farm configuration therefore does not apply, and there is no question of number of sessions being used.

3. In a single conference call with 6 participants, there is one session. When you configure: dspfarm confbridge maximum sessions 10, it means you can setup a maximum of 10 conference calls, each with a maximum of 10 participants.

. The number of Transcoding/Conferencing sessions are limited to the number of DSPs available in the DSP Farm.

. Each DSP can host only one conference session. Each Conference session is limited to 6 participants.

. Each PVDM comes with 3 DSPs, and therefore supports a maximum of 3 conference sessions.

. Each NM-HDV can have up to up to 5 PVDMs, for a maximum of 15 (3x5) DSPs. With 15 DSPs, you can have up to 15 conference sessions, each with a maximum of 6 participants. So the total number of participants supported by a fully populated NH-HDV or NM-HDVFarm is 90 (15x6).

Regards,

Michael.

[kitog]

First, thanks you all for the reply, it realy mede things more clearly now.

one more thing, can you describe in which scenarios does the transcoder is beening use in an IP TelePhony environment with centrelized CCM?

Thanks, Kito.

[dugrant · Accepted solution]

The transcoder will be invoked whenever you make a call from a G.729 region to another device that does not support G.729. CCC and CRS are the most common applications that do not have support for G.729.

[patrick.hurley]

Hi Michael,

You contradicted yourself within 3. where you say that you can have 10 participants and then below say maximum is 6.

I was just working with a customer and we had 18 participants on a meet me bridge number.

I am confused about all the conflicting numbers. What is the real limit?

[paul.harrison]

Kito,

Michael is correct on point 3.

according to .

http://www.pluscom.ru/univercd/cc/td/doc/product/voice/c_access/config/dsp.htm

Each conference session configured can handle up to 6 participants, so if you configure 10 conference sessions then you can have 10 x 6 party conferences.

Paul