IPCC Express best solution for remote Branch

Unanswered Question
Mar 8th, 2007

hi to all,

We have a customer with this equipment in HQ: 2xCCM 4.1 in cluster, 1x3845 with 3 PRI, 1xIPCC4.0(4) installed in G.711. At remote site have: 1x2821 with 3 PRI and a wan link to HQ of 512Kb/sec. The remote site have a different region that use a G.729 codec to talk with HQ. I configure in HQ router (3845) a transcoder, but I?m not sure that this can work correctly with remote agent that use G.729 codec for talk with HQ region, and I don?t know if the transcoder is used for all conversation durations, or only until the caller is connected to an agent.

Other problem is that the customer need to use a centralized IPCC also as IVR for remote branch so I suppose that the WAN link is inappropriate; how much bandwidth for a call is needed?

Someone can tell me what is the best solution for my infrastructure?

thx a lot

Franco Mastroeni

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Overall Rating: 3 (7 ratings)
lpezj Thu, 03/08/2007 - 06:29


I think that, in a first view, you can change the IPCCX codec from G.711 to G.729 or change your IPCC Express to the branch office.

To change the IPCCX codec you need to reinstall IPCCX and change the codec during this reinstallation, but you will mantain the current data and configuration in IPCC Express. You have to keep in mind that you will need to change the G.711 custom prompts that you have recorded to G.729.

Hope this helps,

Juan Luis

Chris Deren Thu, 03/08/2007 - 06:31

You will not need a transcoder for IP phone to IP phone conversations, the phones transcode the stream themselves.

You will need a transcoder if phone at the branch location needs to call into IPCC script, unless you create a new G711 Device Pool and assign it to all CTI ports, this way whenverver someone calls into IPCC they will always use G711. Off course the drawback of this is that more bandwidth will be used over the WAN. But these are your 2 options:

1. use transcoders

2. use G711 codec for IPCC CTI ports

3. re-run the IPCC install and select G729

Also, when a call comes in to the remote branch GW, and you point it to the IPCC, same logic applies, you'll either need a transcoder to use G711 between the GW's Device Pool (Region) and the CTI ports Region.

HTH, please rate all posts!


Telematic Thu, 03/08/2007 - 06:47

thx for your reply, I can't move the IPCC to remote branch because in the HQ I have about 60 agents that work already. When a call come from the remote branch GW and go in to IPCC i need a transcoder in my situation, but i can't understand if the transcoder is nedeed for all conversation or only when the call is answered from the CTI and not need transcoder when is connected with the agent in the remote branch.


Chris Deren Thu, 03/08/2007 - 06:52

You should not have to move any servers, the transcoders will only be needed for calls sent to IPCC, and only the calls that came in as G729, in your case all calls from the remote site. You'll need transcoders on the HQ Router.


Telematic Thu, 03/08/2007 - 06:59

thx again Chris for your quickly reply...but i need to know how much PVDM i need for maintener a maximun of 15 calls from the remote branch and IPCC in the HQ? and it's enough having DSP only in the HQ router?and, I understand, the transcoder is not used when the calls that come from the remote GW, after the prompt, is connected to the remote agents?


Chris Deren Thu, 03/08/2007 - 07:03

You will need 2 PVDM channels for each call, so for 15 calls you need 30 PVDM channels, the good thing about transocding PVDMs is that you can share them between voice channels and transcoding, so for example if you already have PVDM2-64 on your GW and you have one PRI taking up 23 channels (assumning only G711 calls are used here, otherwise 46), you have 41 channels remaining. When you go to configure transcoding profile and type in "max sessions ?" it will tell you how many you can provision.


Telematic Thu, 03/08/2007 - 07:15

yes what you say is right, but i haved configured a dspfarm and i have 2xPVDM2-32 free and when I type max sess I see only 32 max sessions and when i try to use the dspfarm I see that a call use 2 sessions. so at the end I have the half of the half of my resources...this is correct?!but like this I need a lot of PVDM...


Chris Deren Thu, 03/08/2007 - 07:27

Correct, each call will take 2 PVDM channels for the 2 call legs. PVDMs are less expensive than bandwidth, one smart man once told me :-)


Telematic Thu, 03/08/2007 - 07:55

that man is a sage man:) ..so at the end for my infrastructure and for having 15 calls simultaneously from remote brach to HQ in G.729, I need about 1x PVDM2-64 for transcoding and a wan link at least of 1Mbps only for Voice infrastructure..my stimation is correct?!


Chris Deren Thu, 03/08/2007 - 08:00

You would not need PVDM2-64 for trascnding for 15 calls, you would need 30 channels on the HQ router (that's where the transcoding occurs), and additional 30 channles on the Branch site for voice teremination (when using G729) which you need anyway.

15 G729 calls will use (depending on layer 2 transport) about 450kbps of bandwidth, as oppose to 1.4 Mbps with G711 including overhead. So, using G729 as oppose to G711 for 15 calls requires 30 PVDM channels extra, but saves you ~ 1 Mbps of bandwidth :-)


Chris Deren Thu, 03/08/2007 - 08:02

Also, keep in mind that the transcoders will only be required while the call is connected to the IPCC while executing the scripts, once a call is transferred to an agent then it will be released as the IP phone will negotiate the codec with the GW!


Telematic Thu, 03/08/2007 - 08:20

yes, but when I configure the dspfarm and i have 2xPVDM2-32 i see only max session 32 and when I try to use transcoder I see 2 session used for a call of this 32 max...why this?...and anouther think is that I read in the IPCC express SRND that an IP Phone call in g.729 with 20 millisecs of speech per packet, require 62.4 Kbps. So 62.4x15=936 Kbps.


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