Case Study: Managing VOIP effectively
Without the right tools, fixing one problem can mean causing another.
By Denise Dubie, Network World | Network World US | Published: 00:00, 29 June 2006
Network managers running voice applications across their IP networks know a thing or two about juggling.
Daily they must track the performance of IP phones, voice gateways, call managers and IP PBXs against that of such data network components as routers, switches, hubs, servers and client machines.
They must determine whether a staticky line is due to a physical problem such as a bad cable or overextended cord, or whether no phone service on a user's desktop means two IP phones were assigned the same IP address. With VOIP adoption growing, network managers' need for management tools has grown beyond monitoring device availability to fine-tuning voice application and service performance.
Ensuring top performance on a converged network typically requires a blended management approach, which couples voice-specific monitoring tools that detect jitter, packet loss, delay and call quality, with traditional network management products providing a picture of device health, port configurations and network availability.
Bringing such tools together gives users a more complete picture of how voice applications impact the data network - and vice versa.
"The VOIP network is highly reliant on how well your data network is performing," says Garrick Sobeski, manager of networks at The Institute for Transfusion Medicine, Pittsburgh. The organisation has about 400 IP phones in its six-month-old Cisco IP telephony system. "We had to make sure our routers and switches were running in tip-top shape, both pre- and post-voice deployment. And we need to monitor the quality of calls in real time."
Sobeski, who oversees a voice network that ultimately will support about 1,000 phones, including those at a second location in Chicago, says he uses Qovia IP Telephony Manager in concert with HP OpenView and CiscoWorks to get a complete picture of converged network performance.
Qovia uses management software and distributed remote appliances that act as sniffers for voice traffic, reporting back performance metrics and notifying when thresholds are missed. With virtual LANs in place to segment voice traffic, and QoS priorities set on his Cisco gear, Sobeski says he gets near real-time statistics on call quality and network performance.
"We can see a display of the CEO's call quality, if we have too many poor MOS [mean opinion score] readings, if call managers are running too high on memory - basically we get visibility into all pieces of the network in as close to real time as I've seen so far," Sobeski says.
Monitoring both voice and data
Scott Peterson, director or network services at Accenture in Dallas, tapped his InfoVista management products to track data and voice network performance. He says when the company - which is undergoing a large voice deployment across some 140 internal locations supporting 130,000 employees - chose a management software provider a few years ago, it went with InfoVista, which had proved its software could monitor both types of networks.
The company also uses EMC Smarts for network management and correlation tools and BMC for its client/server management product.
"We have had the voice network growing for about five or six years and we picked our management tool two years ago," Peterson says. "We are trying to use the fewest number of management applications to get visibility into our entire network. Subtle changes in IP traffic can be enough to impact voice."
As VOIP adoption grows, so does the number of vendor tools available that deliver details on IP telephony performance. Recent research from Infonetics shows the number of people subscribing to VOIP services will almost double in 2006, to 47.3 million.
The consultancy also released results from a study of some 240 businesses that use VOIP now or will by 2007, as well as the results of 450 shorter interviews to determine VOIP adoption rates. Among large businesses, 36 percent already are using VOIP equipment and VOIP services. Only 23 percent of midsize and 14 percent of small businesses have adopted VOIP gear and services, the study says, but VOIP adoption by small businesses will triple by 2010.
Vendors such as Brix Networks, Clarus Systems, Netreo, Qovia and Viola provide voice-specific monitoring tools to help customers track performance.
Voice equipment makers such as Alcatel, Avaya, Cisco, Mitel and Nortel provide management applications with their gear to help network managers collect data on voice devices, and management software and appliance makers such as Apparent Networks, InfoVista and NetQoS add voice performance metrics to their products that detect failures and degradations on data networks.
Probing for real-time samples
Michael DeDecker, network administrator at Warner Pacific Insurance Services, uses Cisco's Unified Operations Manager product to keep tabs on the vendor's CallManager 5.0 product as well as to ensure that performance stays in line for about 500 devices and 125 users.
Unified Operations Manager uses probes distributed on the network to collect real-time samples of voice quality, DeDecker says, which "beats troubleshooting by 100 times because you can see actual delay issues at a remote site."
DeDecker doesn't credit Cisco management tools entirely for his success with voice, however. When the company built a new facility in 2003, his IT shop decided to move to VOIP. He says he constructed the site, "maybe even over-provisioned it a little," to support voice applications running on the data network. He also has virtual LANs for voice and data set up to segregate traffic and ensure that QoS policies can be applied to voice as needed.
"With voice, video and data on one wire, you have to worry about latency, delay, bandwidth constraints - and mostly, how other programs are affecting the voice traffic," he says. "If you are going to invest in voice, you must also invest in something that will give you insight into how it performs. You want to have that warm, fuzzy feeling that voice and data are coexisting happily."
Kevin McPhee, manager for network control and converged solutions at Coventry Health Care in Virginia, says he uses Avaya's Converged Network Analyser and VOIP Monitoring Manager because the products include intelligence about the gear he has installed. With eight sites using VOIP and total of 30 planned, McPhee says Avaya tools help him monitor voice alongside his data network to determine how the two impact each other, with voice running on VLANs. Still, he says he'd like to collect more data from the phones themselves.
"We can see the phones on the network, but we can't see into the phones," McPhee says. "I'd like to be able to collect statistics such as frame errors and jitter by logging into the IP phone."
Others also believe voice equipment makers could better tweak their management tools. Tim Ryan, network manager at California's City College of San Francisco, says Alcatel's OmniVista management applications help him monitor performance across his VOIP network with nine campuses, 1,800 phones, 500 analogue ports and the vendor's OmniPCX.
He uses Alcatel tools in concert with InMon software, which monitors the data network for error levels, utilisation, dropped packets and latency. Alcatel's product helps him monitor trunk utilisation, measure individual call quality and collect faults, but he says the alarm logs could be a bit more intelligent.
"It can be a challenge to get a lot of alarms that could or could not be affecting the voice services," Ryan says. "I'd like to see more intelligence on the severity of the alarms and more familiarity with our system and how it alarms."