Cisco 2951 ISR Router

Answered Question
Jan 14th, 2010
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Hello all,

I want to put together a quote with the Cisco 2951 ISR router as my gateway router.  However when I go to check run the DSP calculator to check for how much PVDM I need there are only 2800 and 3800 series routers available in the application.  How do I calculate what additional PVDM I will need for this router?

Please let me know your thoughts/suggestions.

Thank you.



Correct Answer by Jaime Valencia about 7 years 4 months ago

I guess this link will make you very happy:

DSP Calculator - TDM Services

G2s included.



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Rob Huffman Fri, 01/15/2010 - 06:28
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Hi Vicky,

The new G2 ISR's are a little different in their PVDM3/DSP support. Maybe these notes might help

All the Unified Communications Bundles on Cisco 2900 and 3900 Series routers include the new Cisco® High-
Density Packet Voice Digital Signal Processor (DSP) Module (PVDM3), which has been optimized for concurrent
voice and video support. The PVDM3 modules support all voice-gateway functions of earlier generations of PVDMs,
and add higher density and more processing power to support emerging rich-media applications.

CISCO2951-V/K9 Cisco 2951 Voice Bundle, PVDM3-32, UC License PAK CON-SNT-2951V

In order to integrate an existing Network Modules (NM, NME) or Extended Voice Modules (EVM) into the Services Module (SM) slot on the Generation 2 ISRs, a network module adapter is required. Similarly, to insert an existing Packet Voice Digital Modules (PVDM2) into the PVDM3 slot of the Cisco 2900 and 3900 Series routers, a PVDM adapter is needed. One adapter is needed for each module that needs to be plugged in and can be ordered during system configuration in the Configuration Tool. These adapters can also be ordered as spares in order to insert any existing modules from current ISRs in use.

Also, check out this excellent Q&A doc;

Q. What new DSP modules are available with the Cisco 2900 and 3900 Series routers?

A. The Cisco 2900 and 3900 Series platforms support the new PVDM3 DSP module as well as the PVDM2 DSP module supported on the Cisco 2800 and 3800 Series routers. You can order the PVDM3 in six increasing densities of DS-0 channel support. Table 6 gives a complete list.
Table 6. PVDM3 Support


16-channel packet fax and voice DSP module

32-channel packet fax and voice DSP module

64-channel packet fax and voice DSP module

128-channel packet fax and voice DSP module

192-channel packet fax and voice DSP module

256-channel packet fax and voice DSP module

Q. Can the PVDM2 and PVDM3 DSP modules coexist on the Cisco 2900 and 3900 Series routers?

A. Yes, they can coexist as long as they are not both installed in the same domain. The motherboard PVDM slots form one domain and each SM slot forms a separate domain. The motherboard domain can contain either all PVDM2 modules or all PVDM3 modules. An SM domain can only contain PVDM2 modules housed by the NM-HDV2 carrier card. If a mix of PVDM2s and PVDM3s are detected on the motherboard, then the PVDM2s will be deactivated, allowing only the PVDM3s to be active. If PVDM2s are detected in service-module slots and PVDM3s are installed on the motherboard, then both will continue to function in their own domain and coexist.

Hope this helps!


victoriabardy Fri, 01/15/2010 - 06:44
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Hi Rob,

This definitely helps.  I wish Cisco would get the dsp calculator tool updated so I can get an accurate idea of what I need for the office I am looking at this router for.  Based on the info you sent I will probably wind up doing a best guess.

Thank you again.



victoriabardy Fri, 01/15/2010 - 07:14
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Hi Java,

You got that right!  This made me very very happy!  Where did you find this?

Thank you so much!



Jaime Valencia Fri, 01/15/2010 - 07:23
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I got this from an internal ISR G2 presentation we had a couple of months ago.

I thought they would replace the old DSP calc with this one but they kept it in a separate link.



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kbyrd Wed, 01/20/2010 - 07:46
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Rob, will the 2900 and 3900 series function as H.323 gateways and DSP Farms for a 4.1(3) version CUCM? I need to get off of the CMM modules we have, need backward compatibility with 4.1(3), and also require new functionality (video) with verison 7.x of which we are about to upgrade. Thanks.

Kapil Atrish Mon, 09/13/2010 - 01:23
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Hi Experts,

I am running the DSP calculator to know the number of PVDMs required for:

HWIC-2CE1T1-PRI2 port   channelized T1/E1 and PRI HWIC

I need it on 2811 and 3945. Unfortunately neither the Old DSP calculator (when I configure 2811) or the new DSP calculator (When I configure 2811 or 3945) show this module under options in HWIC slot. This is a PRI and must have PVDMs, correct? I know I can give PVDM2-64 or PVDM3-64 however curios to know why this module is not listed in DSP calculator against HWIC slots.Need some expert comment to get my understanding right here.




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