Monitor & Manage VoIP

Testing & Diagnostic Tools Help IT Improve VoIP QoS As IT managers increasingly add VoIP to their network infrastructures, they are oftentimes finding themselves the victims of Murphy’s Law. Even if implementation goes smoothly, once VoIP is running, they are running into glitches with audio quality that range from gaps in speech and crackle over the line all the way to dropped calls. Part of the difficulty is that it is often hard to plan ahead for the kinks that will be caused as a result of the daily changes that occur over any organization’s network. “The concern that they have in terms of the long-term success of the service is just how dynamic an IP network really is,” says Jim Vale, product manager for VoIP intelligence at Network General (www.networkgeneral.com). “Once the VoIP service has been implemented, there will be many, many changes that come to the IP infrastructure. So day zero, typically a lot of customers have a good confidence in their implementation, and they do their homework, but really the real concern is what happens after that service is up and running after a three- to six- or even 12-month period of time.” Because of expectations of high availability when it comes to phone use, there is no room for these kinds of problems. In order to keep users and executives happy, and keep their own backsides out of hot water, IT personnel must find better methods and tools to monitor VoIP that go beyond the standard network monitoring fare that they are used to. Sniffing Out Potential Problems The typical network monitoring tools and best practices aren’t cutting it for VoIP troubleshooting because they aren’t specific enough, Vale says. “In the past in networking we would talk about things like baselines which were ‘What is the utilization on the network over time?’ And relative to Voice over IP services and giving them predictive quality operation on the network, those kinds of measures simply don’t give you sufficient information,” Vale says. “What you really need to understand are what are the applications out there and what are the demands that they put on the network in very small windows of time that can stretch a router or switch processing and lead to degrading of quality for Voice over IP packet services.” Problems such as pops in the line can occur from LAN congestion, access link congestion, load sharing, and many other network-related issues. Tools Of The Trade In order to understand these issues, VoIP analysis and monitoring tools should not only be able to quantify and measure QoS issues but to also trace them to their cause on the network. Network General’s VoIP Intelligence product line extends this vendor’s typical network-monitoring technology offered through Sniffer InfiniStream to go back through monitoring data from past calls to really pore through voice metrics and figure out the trends that are affecting voice call quality. IP networks can be analyzed for latency, jitter, and packet loss to help IT managers figure out how to tweak their network to improve quality of service. Similarly, Agilent (www.agilent.com) provides such analysis as a part of its Triple Play Analyzer, which also provides analysis of the network for video on demand and IPTV. It gives users the ability to measure voice quality via predictive MOS (mean opinion score). It analyzes and diagnoses problems that may be at the root cause of low QoS and provides those drilled-down measurements of IP performance indicators that directly affect VoIP services. Another vendor is Empirix (www.empirix.com), which offers its Hammer Voice Quality Test Suite to provide a comprehensive set of monitoring tests that score based on not only MOS but also several other algorithms. It also provides voice activity detection measurement, echo cancellation measurement, and speech latencies. The product is meant to be packaged with Empirix’s Hammer Packet-Sphere Network Emulator, which correlates network activity with voice quality scores to allow for fine-grained VoIP troubleshooting. Radcom (www.radcom.com) is also a part of this market, selling the analysis tool Omni-Q. Based on data collected by VoIP monitoring probes distributed at various network points, the Omni-Q central management module aggregates data and stores data in an Oracle (www.oracle.com) database that can be accessed through a Web-based analysis and reporting tool. Implementing a tool such as one of these can help IT departments improve their quality of service and confidently scale out VoIP implementations that may have been held up at the pilot rollout stage due to concerns from users.