PVDM-32, 1 T1, no meetme conferencing?

Answered Question
Dec 18th, 2008

Hello,

I am a bit new to CallManager Express, and I could use some help understanding DSP allocation. I just recently upgraded to CME 7.0 and would like to test out meetme conferencing. I have a 2821 router with a PVDM2-32, a VWIC-1MFT-T1 for my primary T1 voice, and a VIC2-4FXO for POTS backup. My understanding is since the PVDM2-32 has two DSPs on it, one could be dedicated to voice call processing and the other to conferencing. I do not need g729, so I do not need any transcoding.

This is a test box, and another DSP module is serveral thousand dollars, so if it were possible to test meetme conferences with just a single PVDM2-32 I would be incredibly thankful.

When I try to configure my dspfarm profile, I am getting the following output, showing 0 sessions available:

TESTROUTER(config)#dspfarm profile 1 conference

TESTROUTER(config-dspfarm-profile)#maximum sessions ?

<0-0> Number of sessions assigned to this profile

When I do a "show diag" I can see the PVDM2-32:

PVDM Slot 0:

32-channel (G.711) Voice/Fax PVDMII DSP SIMM PVDM daughter card

!snip

Product (FRU) Number : PVDM2-32

Could anyone help me out and let me know if my understanding is wrong, and I would need another DSP to do conferencing, or if there is something I can do.

Thanks!

-Eric

Correct Answer by Jaime Valencia about 8 years 2 months ago

yes, that would take only 14 channels and you should be able to configure the CFB, sometimes you need to reload the box after shutting down all the interfaces because they won't de-associate the resources. just in case.

usually the way to do this is interfaces first, other resources later, but you might want to do it backwards to make sure you get the whole DSP.

this applies to all platforms just in case you see the same in the future, it's the most common issue when you get the <0-0> option for sessions. that's why a good planning of features needed includes enough DSP resources, DSP calculator makes life easier for this.

HTH

java

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Jaime Valencia Thu, 12/18/2008 - 13:33

conferencing demands it's own DSP, a WHOLE DSP. meaning 16 channels. if you have a T1 and 32 channels that alone takes 23 channels. add the 4fxo and sums 27 out of 32.

the only way you could have conferencing with HW is to add another DSP, if you want to test the only two options would be to use only 14-15 channels of the PRI and no FXOs or just the FXOs to leave enough resources.

you need to take out all the config and shut down the interfaces to free the resources and then configure a CFB

HTH

java

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emphillips00 Thu, 12/18/2008 - 13:50

Hi Java,

Thank you very much for the reply, that helps a great deal! This is a test box, so I could definitely cut the T1 down to 4 lines and we would be able to test it out.

I did not think about the T1 taking one channel for every available DS0 channel, but that makes sense.

I will drop the T1 down to 10 channels and leave the FXO card in, so that should free up a whole DSP, correct?

Thank you again for your reply!

-Eric

Correct Answer
Jaime Valencia Thu, 12/18/2008 - 14:02

yes, that would take only 14 channels and you should be able to configure the CFB, sometimes you need to reload the box after shutting down all the interfaces because they won't de-associate the resources. just in case.

usually the way to do this is interfaces first, other resources later, but you might want to do it backwards to make sure you get the whole DSP.

this applies to all platforms just in case you see the same in the future, it's the most common issue when you get the <0-0> option for sessions. that's why a good planning of features needed includes enough DSP resources, DSP calculator makes life easier for this.

HTH

java

if this helps, please rate

emphillips00 Thu, 12/18/2008 - 14:04

Thanks again Java, that is fantastically helpful!

I did try the DSP Calculator, but I was obviously using it wrong, because I put the two WIC cards in, but it only said I needed 4 DSPs.

I will give it a shot later tonight and let everyone know how it goes!

-Eric

emphillips00 Fri, 12/19/2008 - 13:29

Hi Java,

I wanted to thank you again for your help yesterday. Reducing the T1's channels did the trick and let me activate the conference.

I have a question now, is it possible to have a conference always be active? For example, after you press MeetMe and the conference line, other users can call in across the T1 and dial the extension for the meeting and join.

Is it possible to have that meeting always be active, and not require someone to press MeetMe first? ie... If no users were in the office to press MeetMe. Akin to the reservation-less conferencing bridges you can subscribe to that charge by the minute.

And finally, are there any good CBT series or books you would recommend to learn CME from the ground up?

Thanks!

Eric

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