As more enterprise companies adopt voice over applications and embrace IP telephony, more vendors are looking at ways to manage their converged networks.

For network managers, VoIP introduces a new performance management paradigm. The addition of voice applications to a data network requires they 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. Ensuring top performance on a converged network typically requires new approaches to management.

Experts argue to manage converged networks the management tools must couple 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.

Companies such as Brix, Cisco, Qovia and Viola have been tackling VoIP management and now others are looking more into network managers' struggle with managing voice on data nets.

For instance, Network Instruments - maker of network protocol and performance analysis products - recently polled a segment of its customer community to learn more about what they find challenging about managing VoIP. The company surveyed about 275 network engineers across the United States between April and December 2006 to gauge the attitudes and concerns around VoIP and management. The results showed many still didn't feel they had the adequate means to monitor voice on their data networks.

Among the respondents, 45% have VoIP running on their network. And another 30% plan to implement VoIP in the next 12 months. About one-third said they lack the ability to monitor VoIP performance and 61% said they felt they had insufficient ability to monitor applications.

Topping network managers' concerns about running VoIP on their nets were being able to monitor the QoS of the VoIP application, ensuring reliability of VoIP applications to perform under heavy use, and ensuring the network can adequately handle the added VoIP traffic.

Specifically, close to half of those surveyed were concerned about being able to monitor voice, about 40% were unsure if their networks could handle voice and more than one-third were uncertain voice would perform under heavy use. And 36% said they thought their existing monitoring tools lacked adequate functionality to monitor VoIP performance.

Denise Dubie is senior editor with Network World.