November 1997

BY DAN MACDONALD

As recently as two years ago, it wouldn’t have occurred to IT organizations to plan for the merger of voice network and IT infrastructures with telephony becoming a computer application, with voice just another data stream, and with high-performance LANs the pipeline. Yet today, such plans are more and more common. According to a recent report (Converging Voice and Data Networks, from Infonetics Research, a networking marketing research and consulting firm), 47 percent of network managers are considering, or planning, to integrate their voice traffic with their computer data on one network.

The result of this integration is voiceLAN, the transmission of voice traffic over a local-area network (LAN) infrastructure, enabling a new serverbased telephony architecture for voice switches, terminals/phone sets, and applications. Today, voice traffic is transmitted across a separate circuitswitched infrastructure, with a PBX or key system (for smaller offices) serving as a centralized switch. Under a voiceLAN scheme, both data and voice and other multimedia traffic are interwoven and switched as frames or cells over the same data network.

VOICELAN IMPLEMENTATION BENEFITS
Compelling reasons to use voiceLANs include network consolidation synergies, superior customer service, increased user productivity and expected cost savings. Consolidating the voice and data enterprise networks and gaining the full benefits of voiceLAN entails a technology migration that has implications not only for the network infrastructure, but also for the PC, the phone set, the PBX, and for the user and the IT organization alike.

Benefits for the User
Current computer-telephony integration (CTI) systems allow data and voice application environments to “talk” to each other, via computer-toPBX links. However, voiceLAN goes beyond CTI which is still included implicitly in this new model. It actually melds voice and data environments. Under the voiceLAN model, voice, data, and video applications share the same set of standards and software interfaces.

Converging these applications produces countless opportunities that leverage the power of both media far beyond what is possible under present CTI systems, and has the potential to give organizations a distinct competitive advantage in the marketplace. The result is improved and fully integrated collaborative applications that are critical for business, and which include predictable and high-quality voice functions.

Benefits for the IT Organization
VoiceLAN eliminates the need for cabling dedicated only to voice. Converged voice/data traffic running over a single “wire” reduces the upfront cost of equipment procurement (cable, patch panels, racks, and installation), cable plant management (dealing with moves, adds, and changes) and maintenance. VoiceLAN also enables enterprises to merge and streamline today’s separate support organizations for data and voice networks. This convergence leads to a more efficient, less costly management structure that spends less time “coordinating” and more time delivering network services and applications to users.

There are potential cost efficiencies resulting from the simplification of the management support structure, and by treating voice as another form of data on the network. Decisys, Inc., summarized these in a chart in the 1996 Guide to voiceLAN Networking. The potential cost savings are the result of:

• Integration of management teams.
• Elimination of dual wiring networks.
• Improved productivity/communications.
• Consolidated network/server hardware.
• WAN utilization.
• Simplified troubleshooting.

Finally, for the most part, today’s PBXs are proprietary, singlevendor systems, making them inflexible and expensive to maintain. VoiceLAN deployment opens the door for the open, client/server model to be applied to telephony, creating a less rigid ven-dorclient relationship.

TECHNOLOGY ADVANCES
Advances in LAN network management have resulted in a more sophisticated and flexible network management system. Voice networks, on the other hand, have traditionally been strong in the traffic monitoring and cost areas. Since the two networks share the same topology in the backbone, since they are both digital, and since the telephone system and its traditional telephone user interface would benefit from the added capacity and flexibility at the workgroup and desktop, it becomes clear they would make ideal convergence partners.

The evolution of switching in the LAN and consolidation of the LAN backbone have made convergence of the two networks more viable than previous attempts with the data network taking the lead, since LANs have higher capacity, greater sophistication, and more manageability. LANs have also become faster and smarter, incorporating such improvements as negotiable quality of service (QoS), lowlatency technologies suitable for delay-sensitive traffic, more sophisticated management features, and increased speed.

The traditional differentiation between communications media such as voice and data networks are blurring. At one time, voice was pegged as being realtime, while computing was considered lagged. Over time, data applications like email came closer to becoming real-time as users increasingly demanded more interactivity, while voice applications have diversified to include storage and forwarding or messaging applications, such as voice mail. As all of these communications media evolve and merge towards multimedia, today’s disparate networks will follow the same path.

Standards are emerging that will also drive this convergence, including network management (SNMP), QoS (RSVP, RTP), multimedia (H.323, T.120), and CTI application programming interfaces (TAPI, TSAPI, CallPath, CTConnect).

VOICELAN ARCHITECTURE
A server-based telephony architecture allows for the traditional functions of the PBX to be broken down into its components and distributed on the voiceLAN network. The switching function of the PBX can be handled by the frame or cell switches of the data network, while the call control function can be moved to a server. Specific telephony applications can also be moved to distributed application servers and integrated with other networked data applications.

QUALITY OF SERVICE
Reliability is probably the single biggest concern for users. When the network goes down, the user immediately reaches for the telephone to call the help desk. VoiceLAN implementation will need to demonstrate value and reliability to the user before the traditional desktop voice device can be removed. In the meantime, PC hardware and software vendors will continue to improve desktop reliability. This is already evident for those users who have migrated from Windows 3.1 to Windows NT.

A major challenge facing IT managers is network prioritization and ensuring that voice can be properly supported on the backbone links (trunks) between LAN switches. Supporting both data and voice over a common backbone LAN infrastructure is essentially a bandwidth allocation issue — making sure that delay-sensitive voice traffic isn’t pre-empted by other data traffic traversing the same links. Various techniques for prioritizing different traffic, reserving bandwidth, and guaranteeing network delay characteristics may be applied.

For the voiceLAN media between the hub and the desktop, the main choice is between Asynchronous Transfer Mode (ATM) and switched Ethernet. Each has advantages, but ATM is clearly better at handling voice’s real-time needs. In the network between the switches, ATM is a crucial requirement — its inherent multimedia capability and its gigabit muscle make it uniquely suited for voiceLAN switching.

For many desktop scenarios, switched Ethernet is a valid alternative to ATM, since it can provide the speeds necessary for demanding applications. There are other networking technologies that can cope with faster speeds than 10 Mbit/s Ethernet, but none of them (such as Token Ring and FDDI) is a mainstream voiceLAN contender.

MIGRATING TO VOICELAN
Achieving the end goal of voiceLAN implementation will be accomplished over time and requires a series of logical steps. Organizations may start the migration at different points, depending on their previously installed equipment, economic issues, or recent decisions regarding meeting customer service demands and strategic business goals. In general, compelling events are likely to precipitate these voiceLAN migration steps. Examples of such events, often designed to simplify management, satisfy growth, or save money, include:

• Maintenance contract renewal.
• New locations or branch offices.
• Voice or data system upgrades.
• Hiring of new people (with new skills).
• Reorganization (downsizing or substantial moves and changes).
• New bandwidth requirements (backbone and/or selected user workgroups).
• Optimizing wide-area access.
• Delivery of training (such as video) to the desktop.
• Improvements in communications via voice-annotated text, or other media.

As events requiring decisions to be made about information technology or services investments occur, organizations should be asking the question: “How do I make a better decision with voiceLAN as my goal?” Organizations must start today to begin factoring voiceLAN into their networking strategy and deciding on a course of implementation which may take 3–5 years. Many of the technology hurdles will be overcome with standards developments. However, today’s issues, such as bandwidth congestion and the need for cost efficiencies, are driving organizations to take a close look at convergent technologies that will address these needs now.

It is intended to provide a broad road map for organizations who want to begin factoring voiceLAN into their network architecture planning today.

Dan MacDonald is director, Advanced Networking Technologies at Mitel Corporation, a leader in voiceLAN networking and voice technologies, based in Kanata, Ontario, Canada. Visit their Web site at www.mitel.com. 

VoiceLAN in the backbone is the first logical step that can satisfy today’s business goals (cost efficiency and network simplicity), and lay the framework for a converged network in the future. Lewisburg Area School District in Pennsylvania benefited from deploying a voiceLAN solution.

Lewisburg was experiencing the problems that many educational institutions face today: a need to automate clerical and administration functions at the administration building, as well as at four different schools; adding phone lines to 242 classrooms for security and improved communications; and bringing on-line the 46 different instructional computer systems in the schools. The cost estimates for running separate voice and data networks proved prohibitive.

To overcome the budget hurdle and meet Lewisburg’s communications needs, Mitel Corporation, a provider of voiceLAN solutions, teamed with a local service provider, Buffalo Valley Telephone Company, and a consultant, EUDNET, to develop a networked solution based on a converged high-speed backbone. This solution not only met the school district’s need for advanced services connectivity within budget, but supports future plans for growth and new services.

The central switching element in the Lewisburg network is NeVaDa (Networked Voice and Data), Mitel’s voiceLAN networking solution, which converges voice and data at each location for transport over the wide-area network using asynchronous transfer mode (ATM) technology. Of the 155 Mbps available, 16 Mbps of bandwidth is dedicated to voice, with the remaining 139 Mbps available for a wide range of current and future data applications.

INVESTMENT PROTECTION
The school district was already leasing Mitel PBXs from the local carrier, so the SX-2000 PBX components and telephone sets were migrated to a fiber-distributed SX-2000 LIGHT PBX, which provides the core voice communications capability within the NeVaDa system. Ethernet hubs already installed at each school were retained for use with NeVaDa.

IMPROVED HIGH-SPEED COMMUNICATIONS
School district administration applications are designed to help school systems meet not only federal regulations, but help the district automate all school administration tasks. NeVaDa provides the necessary bandwidth to make running administration applications functions such as student enrollment, attendance, report card generation, payroll, human resources, finance, and inventory and food service across the multisite network as fast as if it were operating on a single LAN.

“We brought our Accelerated Reading Program on-line, so students can test themselves and track the results,” noted Thom Fantaskey, director of technology, Lewisburg Area School District. “It really is an enabling and encouraging use of the technology that benefits our students.” On the voice side, teachers and administrators are now able to send and receive voice mail via a common system. Pre-recorded messages enable students and parents to call for homework assignments, lunch menus, and event calendars, and to check for early closings or late openings due to weather or other conditions.

FUTURE-PROOF SOLUTION
Based on a multiphase approach to implementing services, Lewisburg is well on its way to meeting its goals. The administration application and voice services are fully operational. Call identification capabilities will be provided for incoming calls. By 1998, the system will automatically call the parents of absent students to confirm that students are safe at home. Students will be able to exchange electronic mail from school to school, and may soon be able to browse their local community library as well.

“By the end of 1997, our students and teachers will be able to access the many educational and instructional sites available on the Internet,” said Fantaskey. “In one year, we will have gone from having to send mail between schools to watching volcanoes erupt via the Internet.”

“The real benefit to the NeVaDa system for Lewisburg is not what it can do for us today,” noted Ed Keller, director of administrative services, Lewisburg Area School District, “But what it will enable us to do this year, next year, and on into the future. It used to take us two or three days to get a budget report. Now I get it in a matter of minutes. It is hard to put a value on having instant access to information.”