Datacomm

March 16, 2004
Elements of convergence: VoIP

Paul Singh

The convergence buzz is everywhere in the industry! One can compare the story of convergence to the story of the blind man and the elephant. Every blind man that touches the elephant describes it differently, depending on which part of the elephant's body was touched.

NEW DELHI -- Convergence could mean the integration of wireline and wireless networks or the integration of local, national and international long distance (NLD or ILD) networks or the integration of telephony and data networks. The fact is that convergence comprises all these things. The ultimate convergence nirvana will only be achieved with an end-to-end IP network, providing multimedia services over any type of media whether wireline or wireless, fixed or mobile.

Today, the majority of voice traffic is carried on TDM networks, using circuit switches with less than 10 percent of traffic being carried on IP networks in the form of VoIP. However, this statistic is likely to reverse in a decade with the majority of voice traffic most likely to be carried on IP. Twenty years ago, when the PC was introduced to the data communications market, conventional wisdom dictated that the PC will never replace the mainframe, but we all know about history. History is about to repeat itself in the telecom world. A simple concept of VoIP introduced about seven years ago is now becoming mainstream.

Early phases of VoIP

Before doing any further comparisons, let us understand VoIP technology, and how and where it is being used. Just like the original PC concept, put all the power in the desktop with the majority of applications focused on individual users. The original concept of VoIP was to use peer-to-peer technology in the form of H.323 as an underlying protocol. Like the early PC model, VoIP technology lacked reliability and manageability of circuit switches. Therefore, the technology was relegated to an immature status until gatekeepers were introduced, which introduced the concept of management of calls so that the service providers could bill and control calls.

Thanks to telecom regulations worldwide, VoIP offered tariff arbitrage opportunities that were taken advantage of initially by ISPs. As regulators couldn't control the advent of VoIP, many of the incumbent service providers joined in the fray, and the technology continued to grow with its use mainly for ILD. Today, Veraz has H.323 media gateways in networks in India.

The next phase

The limitation of H.323 in building scalable and manageable open networks was apparent. Therefore, about five years ago, it was clear that the time was fitting for something new. The telecom industry set out to develop new protocols and architecture. This divided the industry into two parallel directions. Two groups merged: One group, which was influenced by the data communications world went towards an SIP architecture with an emphasis on edge-based services. The other group, which was influenced by telecom started with the MGCP protocol that later became H.248.

The monolithic structure of circuit switches was broken into three open distributed layers, with media gateways as the hardware layer providing TDM to IP conversion and compression, while interfacing with standard protocols to the softswitch. The softswitch interfaces to the SS7 signaling network. It made intelligent call decisions directly to the media gateways and or other IP devices to make or break the connections as needed to complete calls.

Why would the telecom workhorse of today, the circuit switch, need a replacement? There are many similarities with the mainframe history. A roomful of mainframe power is available in a desktop computer, thereby reducing capex and opex significantly. The same can be said for the next-gen technology in telecom. For example, one of Veraz's customers has an over 80,000-port network and can fit all of its equipment in four racks, while an equivalent TDM system would require 8 to 10 times the space and power needs.

Either the computer vendors completed the entire mainframe programming or it was completed by a few elite programmers. Consequently, this restricted the growth of the market. What resulted was the era of distributed computing, and the number of applications, and the number of application programmers increased precipitously. The same is now starting to happen in telecom, wherein, the next-gen products offer industry standard open interfaces such as SIP and PARLAY. These industry standards offer new opportunities for creating new applications and services for telecom, which so far, were dependent on TDM switch vendors such as Alcatel, Siemens, and Lucent.

As the world transitioned from mainframe to distributed systems, and Internet technologies became ubiquitous, distance and time issues disappeared. It created large outsourcing opportunities for countries like India and China. As VoIP takes hold of the telecom landscape, location will become a non-issue. In fact, it will be possible to provide telecom services to a US city from another city in India or vice versa.

Telecom is not solely about voice any more; it is about offering voice, data and video together so that service providers can recover their investments in the fiber infrastructure faster. Such services need a new system and thinking, based on next-gen VoIP technology.

The difference between wireline and wireless is disappearing, and so, service providers will have to offer service anywhere using any media with the best available network. Possessing one integrated network to offer these services is the key to survival for service providers - to keep opex low, and customer satisfaction high. This kind of integration is best accomplished with VoIP technology.

India can benefit from the arrival of new technologies in the switching world. Rather than deploy the old TDM technology, countries have stopped spending additional money. Service providers in India should take some bold initiatives and deploy next-gen VoIP technology in ILD, NLD, and local wireline and wireless networks. This gives India more opportunities to be competitive in the global economy and open possibilities of rapidly deploying new services for end users and lower opex for the service providers.

(The author is vice president, business development, Veraz Networks.)