Monitoring DSPFarm Resources

[Dave Agro]

I'm working on configuring a new 4431 ISR to replace our 3845 router.  Mistakenly there appears to not be enough PVDM channels to do what we used to do.  On the old router we had 192 total channels, now just 128.  On our current configuration we have 10 sessions for Transcoding and 20 sessions for Conferencing configured. 

I'd like to find out exactly how many resources we are currently using, but I'm having a hard time.  Cisco TAC pointed me towards "show sccp connections" command which seems to show xcode sessions, but not conferencing.  In fact, I tried a conference call and noticed my sessions jumped from 2 to 6, but all were listed as xcode type.

Is there an SNMP OID that I can monitor to see sessions in use so I don't have to constantly login to that router and run the command just to see what's being used?  Additionally, is there a better way to calculate how many xcode and conferencing sessions we might need?

[Jay Schulze]

You tried using perfmon in RTMT?

I'm sure there is an OID for it. Should be pretty easy to find.

[Deepak Mehta]

It will depend upon the type of codec .For example low complexity codec G711 will take less number of channels whereas high complexity ILBC will take more .

you can use cisco DSP calculator which DSP is suitable based on the requirement

https://supportforums.cisco.com/document/124351/dsp-calculation-tdm-voice-service-and-video-conferencing

If you want to learn the math behind this then check this arcticle by cisco expert Ayodeji.

https://supportforums.cisco.com/document/123126/cisco-pvdm2-and-pvdm3-dsp-creditmips-allocation

[Dave Agro]

I've tried to use the calculator, but the first question it asks is if what type of T1/E1 card you have.  This router has none, which made me wonder if the DSP was even required.  Although when I run the command it does show it's being used for xcode sometimes.

[Deepak Mehta · Accepted solution]

As jay suggested you can use RTMT for monitoring the conf bridge or transcoding resources utilization on real time.

This is a list of the number of channels supported/available on the various flavors of the PVDM4 categorized by the complexity of the codecs that are supported.

Based on the type of codec ( high ,medium,low) you are using for your calls , you can provision the number of sessions.

Complexity                     PVDM4-32   PVDM4-64  PVDM4-128  PVDM4-256
Low-Complexity Voice        32            64                    128             256
Medium-Complexity Voice   24          48                      96            192
High-Complexity Voice       16           32                      64            128

[Dave Agro]

How did you get to that screen in RTMT?

So far from what I can see using the graphs, it seems we never use the "Conference" portion of our DSP Farm.  Even when I make a conference call and run "show sccp connections", I see 4 xcode show up, no conference.

[Dave Agro]

How did you get to that view?

So far in my testing, and what I can see from the graphs, we only ever use xcode.  Even when I initiate a conference call, it just takes up 4 xcode of type pass-thru which seems to not even count against DSP Farm resources when I look at "show dspfarm all".

[Deepak Mehta]

Hello Dave,

You will get the screen on RTMT also make sure whatever CFB your phone is using in via MRGL , you are selecting the same while monitoring via RTMT

Go to perf monitor

1) Select the subcriber where conf bridge is register ( check in CFB config to which sub it is register to

2) Select the IOS Cisco Hard conf bridge on the performance monitor page for that sub

On perform tab on bottom right click and select new and check table view ,this will list the data in table view.

[Deepak Mehta]

- Make sure you check conf bridge which is assigned to phone MRGL.

- You can see in CFB config to which CUCM it is register to and select the same node in RTMT perf monitor.

- Also to get a table view right click on bottom - perform counter and check table view option as given below.