Digium Switchvox Phone System Deployment at Casper College


Definition:   VoIP is short for Voice over Internet Protocol, which a category of hardware and software enabling people to use the Internet as the transmission medium for telephone calls rather than by traditional circuit transmissions of the public switched telephone network PSTN.

Digium D70 phone

VoIP deployments for institutions the size of Casper College (700ish phones) have traditionally cost hundreds of thousands of dollars.  The bigger the school and the more phones….the more “Benjamins” required.  At Casper College, multiple phone upgrade paths were explored, and our best guess cost estimate to upgrade with a traditional vendor provided solution would have ranged from $500,000 to $1,000,000+. The lower number ($500K) would only provide basic functionality and would provide less than half of the phones needed to service the campus with a single VoIP phone platform.  Additional phones and additional features such as unified communications,  support of our emergency notification services or public address system functionality would likely drive the cost to the upper part of this range.  Although many organizations are also considering hosted or cloud based solutions, our belief at this time is that these solutions are still cost prohibitive for our institution.  So how did we decide to provide great VoIP technology for all of Casper College and not break the bank?  Digium Switchvox is our answer.  The objectives of this VoIP project are to:

  • converge three (3) phone systems to one (1)
  • Standardize handsets across campus
  • upgrade and improve our voice communication capabilities
  • get the greatest value for our initial investment
  • drive our recurring costs to near zero

Achieving these objectives will allow us to put more financial resources into supporting the primary goal of the institution: teaching and learning.

Normal VoIP Project Assumptions

•There is no avoiding VoIP – enterprises must replace legacy phone equipment as it nears end-of-life and support options disappear.

Organizations often experience real infrastructure strain before justifying the high cost of implementation.

•Generally a short term ROI is unrealistic – IP Telephony is a long term investment.

•Even with a strong need to address operational risks, IT leaders must still assemble a formal business justification to gain buy-in for the project.

•Proposals must incorporate non-financial factors, including improved operational flexibility and access to new features. If you can’t communicate the business value of these areas, you won’t be successful.

•VoIP is now firmly established as a viable business communications technology. Enterprises face inevitable upgrade scenarios and must get up-to-speed with the technology to understand key decision factors.

•The biggest challenge  is preparing the case for transition. Institutions are widely realizing benefits such as improved collaboration and streamlined administration – but the cost to implement VoIP remains high.


Definition:  A PBX (private branch exchange) is a telephone system in an enterprise which switches calls between enterprise users on local lines while allowing all users to share a certain number of external phone lines. The main purpose of a PBX is to save the cost of requiring a line for each user to the telephone company’s central office.

Casper College phone services through May 2013 were a mixture of:

1)  600 analog handsets driven by a legacy Avaya PBX which is not supported by Avaya, although we do have a third party maintenance agreement.  Parts are difficult to find and are becoming more so as time goes forward.

2)  90 Cisco VoIP phones driven by a Cisco Call Manager Express (CME).

The 90 Cisco phones were deployed in 2011 and although there were about 700 total phones on campus, financial constraints dictated a smaller deployment than would support the entire campus.   The two systems running side by side created technical challenges and incompatibilities which would never really let campus users experience the communicative power of a world class phone system.

At first glance it might appear that expanding the Cisco would have been the correct path forward if a VoIP solution is direction the campus should move.  However, Our CME solution would scale only to approximately 150 phones.

Even if we continued with a Cisco solution the Call Manager Express solution would have to be discarded and replaced regardless of the final solution, as that solution will not scale to handle our entire campus.

Our strategy to overcome these challenges and consolidate our phones to a single platform was finalized in the spring of 2013.  To do this, our path forward has consisted of what on the surface may seem an unusual approach.  We  added a third product to the mix, Digium’s Switchvox VoIP phones, which in the short run would add greater complexity to our environment.  In the fall of 2012 we installed Digium Switchvox software on existing server hardware in a virtual environment.  Digium Switchvox is the commercially supported version of the open source Asterisk Phone System.

Digium is the business built around a commercial deployment of Asterisk by the founders of Asterisk.  They license a series of commercial resellers who support and implement the Switchvox phone system.

This may seem minor, but was a key part of our strategy.  A successful deployment at Sam Houston State University of 6000 VoIP phones running Asterisk turned into a failed deployment in 2009.  After the deployment they had to move back to a proprietary Cisco solution after losing key staff with Asterisk specific knowledge who were instrumental to the 2006 deployment.  Would the outcome have been different using Digium, the commercially supported version?  I would suggest yes.  At my previous job, we successfully deployed a 250 phone  Digium solution  in 2011.   For  Casper College, we believe having the commercial support of a Digium reseller is a strategic risk worth taking as we will drive out recurring costs to near zero.  It also helps that the initial cost of the system allows us to actually take on this project.  The initial cost of a Cisco VoIP solution for the entire campus was simply out of reach.

Let the VoIP Adventure Begin

Definition:  A Dial Plan is A telephone numbering scheme used in telecommunications to assign telephone numbers to subscriber telephones or other telephony endpoints. Telephone numbers are the addresses of participants in a telephone network, reachable by a system of destination code routing

Definition:  POE  Power over Ethernet is a technology for wired Ethernet LANs (local area networks) that allows the electrical current necessary for the operation of each device to be carried by the data cables rather than by power cords.

Prior to considering a VoIP deployment we made a major investment in POE switching infrastructure which is being deployed during the phone deployment.  The deployment of the phones is ultimately dependent upon the placement of the POE switches.  The placement of the POE switches is dependent upon various power upgrades and scheduling installations to provide the least disruption to the regular campus schedule.

Following the successful install of the Digium software on existing hardware in the spring of 2013, we began with a test of approximately 20 phones within the IT department.  The VoIP software itself runs in a VMware virtual environment on existing HP c7000 blade hardware consisting of g8 bl460c blades and virtual connect switches.  The storage for this environment is the Lefthand p4000 series SAN.  Although the software version of Switchvox is not supported directly by Digium, it is supported through NP Info who is part of the Digium  reseller network.  This was another strategic risk we were willing to assume.

This initial step of installing 20 test phones included the installation of an Adtran Digital to Analog Gateway ($1000ish) to allow us to communicate with the core of our system   This step brought us to three (3) integrated and functioning phone systems.  From this point the plan was to converge three (3) different telephony systems on our campus (Avaya/ Cisco CME/Switchvox) with Digium handsets that provides  reliable, secure, scalable, and enterprise-wide communications platform designed to meet our organizational needs today, and into the future. Although all capabilities will not be initially rolled out, our solution requirements included, among other things, centralized administration, inter-site dialing and directory, advanced PBX features, inter-site voice and fax mail with unified messaging, inbound call center functionality, in-house conferencing for audio and video, user-aware presence, instant messaging, user mobility, site survivability, emergency services, and support for remote and home office workers.

Via dial plan, the extensions on all three systems need to be able to reach all extensions on all three existing systems, as well as external voice communications through the entire process. The project plan must facilitate decommissioning existing Cisco and Avaya  Systems per phase in plan listed below. Following the deployment of the 20 test systems, the phased provision of  traditional phone handsets, analog gateways (for fax , fire and elevator) and other services included.

At my previous job, we successfully deployed a 250 phone Digium solution in 2011 so I was very familiar with this solution. However, I am not a believer in doing things because that is always how we have done it. Therefore, to make sure we wanted to move this direction we decided on further testing. Normally, enterprise solutions from Digium come in an appliance based format. My past experience was pretty solid, but our situation in Casper was a little different. To deploy the appliance based solution we would have to buy multiple appliances and daisy chain them together to provide the capacity needed as the largest capacity appliance supports about 600 users. This would be very doable and still more cost effective than many of the other enterprise solutions available but still not necessarily the solution we wanted. we were sold on as the server based solution is not officially supported by Digium but rather through their network of re sellers. In the fall of 2012 we set up a test environment with Digium Switchvox software on existing server hardware in a virtual environment by purchasing the software through Switchvox reseller NP Info.

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