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Cisco MGCP gateway (PRI) support NOW in VNQM 4.1 RC

In the last release of VNQM we brought the VoIP troubleshooting for your Call Managers. Those of you who maintain VoIP company infrastructure are probably familiar with the VNQM call signaling topology resource:


This resource contains devices "1005 & 1041" which are typically gateways. These devices connect your internal VoIP sub-system to the line of your data/voice provider(s). You may typically hear "PRI or PRI Gateway" when talking about inside out or outside in VoIP connectivity. What is PRI? The definition says that PRI (Primary Rate Interface) is a telecommunication standard used in the Integrated Service Digital Networks (ISDN), for carrying multiple DS0 voice and data transmission between two physical locations. More technically, a PRI is a type of VoIP line that provides up to 23 separate 64 Kbps B lines and one data channel like with 64 Kbps in a T1 configuration (typically USA) or 30 B lines and one data line in a E1 configuration (typically Europe).

PRI is quite popular today among businesses because of many benefits it has:

  • Scalable technologies that can grow or shrink with your business
  • Low cost
  • Use of existing PBX system technologies
  • Multiple sites can be connected into the same system eliminating maintenance and installation charges across locations
  • Doesn't impact end-users (can dial the number as they were used before)
  • Increased high-tech communications options
  • Can be managed remotely via web-based consoles

And this "PRI Gateway" is something that VNQM 4.1 can now monitor and brings you an another piece of information to solve your VoIP problems. To be very specific, in the case of VNQM 4.1 it's about Cisco devices (MGCP gateways) that have support for PRI.

You, Thwack users, had many dicussions or feature requests (here or here), about how to see utilization of your PRI trunks. You could also read about PRI in a Geek Speek blog post .

VNQM 4.1 RC is ready to be installed on your production and it is fully supported by SolarWinds support. If you are a IPSLA/VNQM active maintenance customer you are more than welcomed to sign-up here for a RC download

What Do We Need to Monitor?

A typical monitoring task for the T1/E1 is to monitor a number of active channels/trunks and their utilization. Some of you were also asking for monitoring of "VoIP vs. Data" ratio on the line. VNQM 4.1 can do both now. We don't use SNMP in this case, because Cisco has a bug in their SNMP implementation which results in incorrect trunk call utilization data being reported.

Now, how do you see this data in VNQM?

  1. Use a new gateway wizard to add your device to be monitored as the MGCP gateway at VNQM settings page

add gateway_cr.pnggateway wizard.png

  2.  When you have successfully added, you should see the list of your gateways on the VoIP summary page:

gateway summary.png

3.  Click on the Gateway from the resource above or in the signaling resource that's part of the call details page. This will take you to the brand new Gateway detail page:

Gateway detail page_cr.png

How to see data distribution and PRI trunk utilization - are you paying too much to your provider?

Gateway detail page_cr 1.png

Data distribution chart can show you a total usage on your PRI gateway, data & VoIP traffic

distribution and you can also drill down to see each trunk utilization specifically. "Trunk Utilization" resource will give you a good historical overview where you may see spikes or gaps over a time.

In our case, we can see that more than 37% of the capacity

is not used over last three months. So why to pay so much to your voip/data provider?

You can reduce amount of lines you need for the connectivity with the outside world.

The same chart could be also used for a troubleshooting of call connectivity.

In a case you reach maximum PRI utilization, your calls can't be connected

and it's time to figure out who is causing such load (CDRs), ask your provider for more bandwidth, or, at least, set up VoIP precedence policies. Gateway detail page_cr - 2.png

Want to see more "per trunk" utilization details? Not a problem:

Gateway detail page_cr_cr - 3.png

How to see problems on a gateway?

It's possible to do it via VNQM search page itself. But, you can save some time and see the most important metric - failed calls, and call quality issues directly on each Gateway detail page:

Gateway detail page_cr_cr - 5.pngGateway detail page_cr_cr - 4.png

In order to see call details, phone numbers, etc. simply hit "Search for all failed calls" link at the bottom of the page and VNQM will filter out Gateway relevant calls only."Easy peasy" don't you think?

PRI & trunk utilization monitoring is a major feature of this release. However, VNQM 4.1 also brings a new web-based reports with charts you may read about in this post.

VNQM 4.1 RC is ready to be installed on your production and it is fully supported by SolarWinds support. If you are a IPSLA/VNQM active maintenance customer you are more than welcomed to sign-up here for a RC download

Level 14

Very nice indeed. But we have Avaya .

Level 14

  Always thought PRI stood for Primary Rate Interface?

Level 7

How do you ignore unused PRI's from the "ALL TRUNKS" view in the Trunk Utilization graph? 

About the Author
I joined SolarWinds PM team in September 2011 and I am currently part of product management team located in Czech Republic . Before that, I spent five years developing networking products and mobile applications.