02-20-2008 09:04 PM - edited 03-15-2019 08:58 AM
Question 1
I have a 2801 with (1) PVDM2-16 and (2) VWIC2-4FXO cards. With this hardware configuration I should have 8 available PVDM channels...right? So why can't I add one conference session, for example:
!
dspfarm profile 1 conference
maximum sessions 1
!
My only option for maximum sessions is "0"
Question 2.
I have a different 2801 that doesn't have any VWICs on it but it does have (1) PVDM2-16. This gateway has a conference profile that allows "maximum sessions 8". The CCM SRND states that the PVDM2 can support 8 participants (I assume per session???). 8 Participants x 8 Sessions = 64. Obviously these numbers don't add up. What am I missing here????
Solved! Go to Solution.
02-22-2008 12:07 AM
One PVDM2-16 has one DSP chip on the PVDM module.
One separate chip is needed for conferencing. You need at least another PVDM2-8.
If you actually use the DSP calculator (I guess nobody does) you see that the minimum requirement for this is
1 PVDM2-16 and 1 PVDM2-8.
No config can save you...
/Martin
02-21-2008 12:23 AM
Answer 1:
2 x 4 FXO card = 8 calls = 16 channels (send&receive)
You need at least another PVDM2-8 for conferencing.
Answer 2:
One DSP chip can support 8 sessions (G711) or 2 sessions (G729) with max. 8 participants.
That's the way it is. The numbers are for calls only, not conferences.
Two things to remember:
You have to change the service parameter in CUCM to allow 8 participants.
The entire DSP chip is used for conference exclusively.
Hope that helps somehow.
I hope you know the DSP calculator:
http://www.cisco.com/pcgi-bin/Support/DSP/cisco_prodsel.pl
Cheers,
Martin
02-21-2008 02:42 PM
Actually, for pvdm2-xx the suffix number (8, 16 32, 48, 64) can be taken directly as the number of voip calls that can be some with g711 and other low/medium complexity codecs. There is no need to divide by two.
For confirmation, use the dsp calculator on cisco website, also useful to determine conferencing dsp sizing.
02-21-2008 10:10 PM
did you enabled the dsp services dspfarm on the right voice card?
if you enable the services in a card where no PVDMs are you won't be able to use them for CFB or XCODING
do a sh diag to verify on which card the dsps are and enable the dspfarm services on that card, then try again
you can do a sh voice dsp to look at the current allocation and determine if you still have free channels
HTH
02-22-2008 12:07 AM
One PVDM2-16 has one DSP chip on the PVDM module.
One separate chip is needed for conferencing. You need at least another PVDM2-8.
If you actually use the DSP calculator (I guess nobody does) you see that the minimum requirement for this is
1 PVDM2-16 and 1 PVDM2-8.
No config can save you...
/Martin
02-22-2008 01:39 PM
Thanks! I didn't know that you need a separate chip. Now it all makes sense.
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