Has convergence innovation been stifled? Interoperability issues—and IP telephony growth—can be addressed with session initiation protocol - Guest Column

Communications News, Sept, 2003 by Iain Milnes

The standardization of IP telephony within the enterprise is expected to lower equipment prices, provide more choice in equipment suppliers and accelerate the innovation for convergence. Unfortunately, enterprise usage of IP telephony has not become mainstream, as predicted years ago. With many companies still maintaining and deploying legacy telephony solutions, innovation with video and other new forms of realtime communication has yet to bear fruit.

The adoption of a standard platform for IP te ment of converged products. Yet, the dominant telephony suppliers have resisted the support of a standard interface into their voice systems--partly because of the difficulty in providing a migration path for customers of their existing products, but mostly to protect their proprietary interests. Many of these companies have made minimal steps toward implementing open standards. They have, or promise to have, support for a standard protocol, but there is little evidence that they have opened access to the full feature set on their systems.

The traditional telephony suppliers have enjoyed decades of revenue streams from the sale, service and support of legacy PBX equipment. Their proprietary technologies lock customers into buying from a single manufacturer. Once a phone system was sold into a company, the end-user was slave to everything that the manufacturer said it could or could nor have in that system--like phones, features, applications and service.

These systems have evolved to be reasonably robust, with a high number of useful features. As customers become aware of the efficiencies of IP telephony, however, these manufacturers' approach to IP telephony has been slow, conservative and largely proprietary. Many of their IP solutions address only the transport of voice over the WAN, which involved the provision of IP gateways that interconnected their own PBXs. This did not make any use of the LAN, so custumers still had to maintain separate voice and data networks.

Some of the traditional telephony suppliers who designed solutions that used IP to the desktop focused on maintaining their existing feature sets and backward compatibility with their existing equipment. While this eliminated the requirement for a separate voice network, the use of proprietary IP protocols left little room for innovation by third-party suppliers.

In reality, their IP telephony solutions were not much better than their legacy systems in terms of revolutionizing IP telephony. Then again, there was not a need to revolutionize while customers were content with their legacy equipment, or IP versions of their legacy equipment.

End-users are beginning to realize that IP telephony makes sense and that the emergence of a standard interface is what the market needs to launch the convergence revolution. With the major manufacturers moving at their own slow pace, however, end-users are left with the perception that convergence is not ready for the enterprise and that there is little choice in phones, devices and applications fur their phone systems.

Fortunately, there is a shining light at the end of this long tunnel to convergence--called session initiation protocol (SIP). With SIP, the ultimate benefit is interoperability among all communications equipment.

Specified in RFC 3261 by the Internet Engineering Task Force, SIP is simpler, more scalable and more extensible than any other IP telephony protocol to date. SIP allows for such advanced features as video calls, instant messaging and presence. Many companies have committed to build on SIP, and some have already delivered on that commitment. With so much activity to ensure interoperability among different manufacturers, usage of SIP for IP telephony, like other standards before, will launch the innovation we have all been waiting for.

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