# DSP Farm Calculations

Thanks for advanced to anyone who can help me better understand this.

I'm trying to calculate the number of PVDM2 DSPs I'll need.  In the documentation, I see the specifications stating that for bearer channels and transcoders, g711u/g711a will need 15 mips per call and g729 will need 40 mips per call. Also, 120mips is needed for each conference call.

How do we use these numbers to calculate what is needed?

If a call comes in on my PRI, and since I'm in the US I assume this is g711uLaw, but is connected to my IP phone at g729.

Is the calculation 15mips + 40 mips for the two calls which comes out to 55 mips.  And then we need to add the transcoding which is going from g711 to g729 so 55 mips + 40 mips. So that end to end call will cost my router 95 mips total?

And for conference calls, is that 120 mips per line dialed in?  Like if 4 people are in one conference call, is that going to cost 480 mips?  And if those 4 calls are all coming from the PRI, is that going to be 4(15mips + 120mips) = 540mips?

Vince

Overall Rating: 5 (1 ratings)

## Replies

Jaime Valencia Wed, 09/08/2010 - 18:52

I really don't use that, there are already tables and other (easier) ways to do that

Configuring Enhanced Conferencing and  Transcoding for Voice Gateway Routers

http://www.cisco.com/en/US/docs/ios/voice/cminterop/configuration/guide/vc_enh_confr_vgr_ps6441_TSD_Products_Configuration_Guide_Chapter.html

or the dsp calculator?

http://www.cisco.com/web/applicat/dsprecal/dsp_calc.html

HTH

java

www.cisco.com/go/pdihelpdesk

Awesome.  I'll try it.  I think I'm just confused over the terminology and whether 'sessions' means the entire conference call no matter how many people are dialed in.

Jaime Valencia Thu, 09/09/2010 - 15:53

Your understanding of session is correct, it's not the number of people in a conference, but how many simultaneous conferences you can have with X people in it (depending on your codec config)

HTH

java