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Converged communications boils down to using different kinds of technologies from different vendors. Olle Westerberg is the CEO of Ingate Systems, Hollis, N.H. He has held senior management positions for more than 10 years with companies such as Ericsson, DSC Communications and Alcatel. One of the largest resellers of caravans and motor homes in the United Kingdom recently wanted to make the jump to IP-based communications, the first step for them on the path to converged communications. This company had about 20 satellite offices they wanted to begin using SIP, and since many of its workers were “road warriors,” the cost savings in migrating employees who were already equipped with dual-mode cell phones to voice over IP (VoIP) was going to be significant. The value achieved by replacing internal phone calls with VoIP and eliminating cell phone charges was helping to drive the migration, once network access translation traversal was resolved.
The next step was to include a fax system into its IP-based network. The fax system was connected through a gateway to a session initiation protocol (SIP) service provider that provided unique fax numbers over IP. These SIP data calls were delivered to the local offices over the Internet. Unfortunately, the interoperability between the VoIP gateway and the SIP service provider was not working properly. This is a common problem. Converged communications today essentially boils down to using different kinds of technologies from different vendors, using several hardware devices, and trying to make them all play nicely together. For this customer, making the SIP service provider and the enterprise server communicate was something that needed to be addressed at the beginning of the project. This is a common challenge with SIP trunking deployments, where getting the IP PBX and the SIP trunking service provider to match up often is difficult. If this is not done right, the SIP trunk, fax system or whatever is being deployed, simply will not work. Some companies address this issue by putting their servers on a public IP address, or they open up firewall ports, making the entire network vulnerable to malicious attacks. None of this is necessary, as there are security devices that can handle converged communications while managing interoperability. Vendors and service providers should address interoperability up front, so installations will not be delayed when these issues arise. All too often, IT departments start a migration to SIP-based VoIP, then try to incorporate a new application or feature (such as connecting remote workers) and get so frustrated with an interoperability problem that they just halt the deployment altogether. What is the remedy? Get the experts involved. Talk to a value-added reseller and/or distributor. They usually have solutions for managing these problems, and can help put together equipment that has already demonstrated proven interoperability. Insist on SIP, not “SIP lite.” Since SIP is the de facto standard for real-time communications, this is supposed to make putting together a SIP-based converged network simple, not only for end-users but also for manufacturers. As new products are developed, if manufacturers adhere to the SIP standards as outlined by the Internet Engineering Task Force, products should all work together in a seamless fashion. Many vendors, however, take the route of “SIP lite,” developing products that are loosely based on SIP and will not work with other SIP products. When making a purchasing decision, look for vendors who strictly adhere to the SIP protocol. Mediate the traffic. Enterprise edge devices can mediate between IP PBXs, Internet telephony service providers and other equipment. They provide advanced routing functionality by adding flexibility to the network. Think of it as a flexible configuration hub that can manage SIP traffic in such a way as to help one device understand and work well with another device. In addition, they can offer enterprise-class security for all SIP applications. Reprinted with full permission of Communications News - August 2008 www.comnews.com.
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