Just a few years ago, voice over IP (VoIP) and IP telephony were considered to be technologies that could not deliver business-quality voice services or the reliability that traditional phone systems offered. However, today, companies like Cisco, 3Com, and Nortel are providing the quality of service and reliability needed to make VoIP and IP telephony the communication medium going forward.

The advantage of this new technology is profound. By combining voice and data infrastructure, organizations will be able to eliminate dual networks, simplify management by utilizing a single support staff, and reduce leased line cost. Benefits become even more apparent with the introduction of productivity-enhancing applications. With the introduction of VoIP and IP telephony technology also comes a change in the way networks are managed.

The traditional support structure
For most organizations, separate networks have been provisioned within the enterprise for data and voice. These have been deployed autonomously and operated in isolation, often implemented and managed by two separate teams. The telecommunications group typically handles everything from phone system installations to add/move/change requests. In your organization, you may refer to this group as the “phone guys.” The phone guys are usually separate from the “computer guys,” which is the staff that maintains the data network.

The distinctions between the two support groups have, for all practical purposes, been easy to identify. If it involved voice or a phone, it was a telecommunications issue, and the phone guys handled it. Any computer- or network-related issues were handled by the data or computer guys.

VoIP and IP telephony vow to change this old set of rules. The convergences of voice and data networks will result in a single support staff that handles both the telecommunications and data systems. If you’re a support person on the data side and haven’t had the chance to get to know your telecommunications staff, now might be a good time. Chances are, you’re going to be working more closely with them and with the technologies they manage exclusively, and vice versa.

Convergence of voice and data
The topics of VoIP and IP telephony are usually preceded by the topic of convergence. Convergence is using an integrated network infrastructure to support both voice and data applications. A converged VoIP network traverses voice communication across intranets, switches, and routers. The traditional Private Branch Exchange (PBX) is replaced by servers. Software-based phones are introduced that allow users to send and receive calls from their computer. IP telephony phones query DHCP servers to obtain an IP address and also serve dual roles as a switch you plug your desktop data connection into.

The key requirements for networks to support converged traffic are quality of service (QoS), digital signal processor (DSP) compression, and multicast. QoS is needed to ensure predictable latency for packets carrying voice traffic. This is achieved by putting packets in priority queues, which can then apply a differentiated class of service for latency-sensitive traffic. DSP technology allows for the compression of voice traffic so it uses less bandwidth. Multicast technology is important in an integrated voice and data network because it allows a data source signal to be requested across a network. The stream is transmitted across the networks once, and multiple users access the content via a copy from a local LAN switch. Because only one signal is carried for multiple users, the stream uses less bandwidth and doesn’t overwhelm the network.

Skills for supporting integrated networks
What do you get when you mix a CCNA with a Windows 2000 MCSE? Well, according to Cisco, the leader in IP telephony technologies, you have someone on the way to being IP telephony certified. Cisco’s newest line of IP telephony solutions, AVVID, runs on two fault-tolerant Compaq servers running Windows 2000. The servers run Cisco’s Call Management software and integrate with Cisco 2600 series or higher routers on a LAN/WAN.

There are numerous other vendors offering VoIP and IP telephony products, and they have the same essential components in common. They utilize servers and the network infrastructure to successfully support and manage such systems. Network engineers and administrators who manage such systems will need to be versed in network operating systems and develop a solid grasp of routing and switching protocols.

The foundation for VoIP is built upon the multiprotocol routers and multilayer LAN switches that are used as building blocks for enterprise networks. If you’re an MCSE or other NOS professional without much knowledge in internetworking protocols and devices, you should spend some time getting training and possibly obtaining a Cisco CCNA certification.

VoIP and IP telephony technology are growing at an explosive rate. Numerous vendors are creating VoIP products and solutions for companies that recognize the advantages and benefits of this technology. The integration of voice and data networks is creating a fundamental change in the telecommunications and data industries. This is due in large part to the convergence of voice and data systems.

The traditional organizational structures made up of a separate telecommunications and data support staff will be consolidated into a single support entity. Those involved in network design, implementation, and support will need to become knowledgeable on internetworking protocols and devices in order to provide the quality of service and reliability that VoIP and IP telephony networks demand.