Telcoms Focus

Northwestern University Turns to Service Assurance: A Case Study

How network administrators verify and measure quality and performance of NU's next-generation IP network and services

• By David Carr
• 09/12/07

While gaining competitive advantages and controlling operational costs with technology upgrades is commonplace in the corporate world, it is becoming increasingly more important for higher education institutions as well, as we strive to attract prospective students.

At Northwestern University, it was becoming prohibitively expensive for us to support our aging telecommunications infrastructure in addition to a separate and expanding Internet Protocol (IP) network. As a result, we decided that it was time to phase out our traditional telephone infrastructure and make the necessary upgrades to support IP telephony and advanced, converged communications services that would ultimately benefit our students, faculty, and staff.

With 18,000 phone lines spread across two large campuses on Lake Michigan -- in Chicago, near the Magnificent Mile, and in Evanston, IL, the first suburb north of Chicago -- transitioning Northwestern's legacy phone system to a Voice over Internet Protocol (VoIP) system would not be an easy task as major network upgrades were required to support the new service. However, we saw this as an opportunity to not only add VoIP services, but to upgrade our IP network to support more advanced communications services and applications.

Since network performance and quality was critical, we needed to address this issue from the onset of the project to prove the network could handle the demands of VoIP and other future Session Initiation Protocol- (SIP-) based services. While the existing time-division multiplexing (TDM) system was at the end of its life, it was very reliable. Those using our TDM phone system rarely experienced any problems, which created high user expectations for the new IP telephony service. Because we function like a Fortune 500 organization, as we prepared to roll out IP telephony services to a large number of users we focused on the same issues that large enterprise businesses do. As a result, managing service quality and network performance was a must for the project to succeed.

To provide quality voice, video, and data services, we knew we would need a carrier-class service assurance solution that could support the project throughout its lifecycle -- from pre-deployment network assessment, to service qualification, to ongoing operational monitoring and service level verification. We needed a solution that could continually monitor service quality across our network infrastructure, and also verify that our IP network and services were running as they should.

We selected Brix Networks' converged service assurance offering. In the first phase of the project, we deployed Brix Verifiers, test and monitoring appliances, at each routing location across our meshed campus backbone network. We used the BrixWorx central-site correlation and analysis software engine to commission active (on-demand) test calls from Verifier to Verifier to constantly measure call quality throughout the network infrastructure.

As we ready buildings for IP telephony services, we install a Brix Verifier at the location to test and monitor performance and network quality to the building. This testing is an important qualification measure to prove quality and performance will meet expectations.

BrixWorx collects the information generated from this continual testing into reports that show a Mean Opinion Score (MOS), which represents a level of call quality. By measuring key performance indicators (KPIs) and MOS thresholds, the application notifies our IT operations group when the network is outside specifications. With integration of the application into our network management system, the operations group receives alerts to quickly identify issues and take the necessary corrective course of action.

We've recently finished the initial phase of the VoIP deployment project during which we qualified the network to support IP telephony services. The network is now being used to provide traditional phone services to targeted users, and we'll soon begin rolling out IP phones to all users in manageable phases.

In the next phase of the project, we will begin installing SIP-enabled phones throughout the university to those members of the community who want to use advanced features. Northwestern has chosen to standardize on SIP for its communications services to offer more advanced IP-enabled services, such as video conferencing and presence capabilities.

As we continue to upgrade our network and roll out new IP-based services, it is imperative we constantly provide a quality user experience to our students, faculty, and staff. By adopting a strategic service assurance approach that is pervasive, continuous, and comprehensive, we now have an effective means to measure, monitor, and assure the quality and performance of our converged services.