Making the call on IP telephony

Using voice over IP (VoIP) as the enabling technology to transport phone calls allows firms to eliminate legacy circuit-switched (TDM) systems and lower equipment costs by converging applications onto a single infrastructure, while browser-based interfaces can simplify system management.

Many IP telephony and VoIP projects now form part of broader UC strategies, which might encompass any combination of instant messaging, presence, conferencing (web, audio, video), unified messaging, social networking and other applications. The technology promises to increase productivity and teamwork, as well as customer responsiveness by integrating IP telephony with instant messaging and presence, or by extending call history and directories to mobile devices, for example.

Despite these benefits, independent research firm Nemartes found that in 2010, only 17 percent of companies had fully deployed VoIP technology. The bulk of those were small and mid-sized businesses as larger firms continue to scrutinise the business case and deploy the technology in a tactical manner – e.g. to replace TDM systems that have reached end-of-life, equip new ‘greenfield’ locations, or to meet the needs of specific job functions or applications. It also found that many firms fail to budget for voice quality management and monitoring tools, and often have to spend more on the LAN upgrade than they originally budgeted for. This is either because they didn’t evaluate the LAN at all or because they didn’t run the appropriate baseline network assessments to determine the actual upgrades required.

Preparing for VoIP
With IP telephony, the question is whether the network is capable of handling VoIP traffic and delivering the quality of experience the end user demands. It is therefore common practice to rollout VoIP to a small subset of the organisation first in order to understand whether the required call quality can be delivered.

It is important to assess whether the network is sized properly in respect of accommodating rising volumes of voice traffic and how it might impact on traffic relating to other business applications.

Establish network baselines
Reporting on performance, utilisation and capacity enables IT operations teams to baseline their current network performance with IPSLA testing employed to assess the impact of VoIP. Having established a baseline of ‘normal’ performance levels, it is then possible to dynamically set accurate thresholds and implement alerts that are issued the moment (or even before) performance degrades or deviates from normal.

Scheduled and on-demand reporting delivers the key performance indicators (KPIs) that, when combined with call quality metrics, provide visibility of the impact of VoIP on both business-application and network performance.
Maintaining full visibility

Once a full-scale VoIP rollout is live, IT operations teams need full visibility into both the performance of the IP telephony infrastructure, and that of the network and the other business applications being supported. This means collecting data including network KPIs such as QoS queue utilisation and key statistics for the call manager server, implementing IP SLA tests to measure end to end latency, and gathering call data via RTCP to understand actual call Mean Opinion Score, Jitter and latency.

With all of this data in one place, normalised and consistent, IT operations teams can easily recognise when call manager performance suffers and assess the impact on call quality and success. If a sudden spike in data traffic impacts on call quality, full visibility ensures that the IT operations team is able to instantly identify the application consuming bandwidth and resolve the issue accordingly.

Why an appliance makes sense
In a converged network environment supporting IP telephony and UC applications, IT operations teams must collate an ever-increasing volume of performance data from a burgeoning number of network elements if they are to gain an understanding of how key services are performing.

Given the limited scalability of legacy performance management tools, an appliance-based solution is recommended because it eliminates the need for additional software, hardware, or external databases, and can be used in standalone or peered configurations in order to quickly provide reports on any indicator, device, or application to be monitored. Furthermore, the proprietary or technology-specific performance management tools available today are unable to deliver the required level of visibility because data must be acquired manually and cannot be overlaid to gain a single view.

The ability to analyse both network and VoIP performance from one system enables faster troubleshooting and problem resolution, and better coordination between network operations teams and telephony teams. Crucially, the ability to troubleshoot issues effectively before they impact on service or network performance means quality of experience and network availability can be assured for all services.