Convergence: The Year Was…?

“Those who cannot remember the past are condemned to repeat it.”

One may wonder how this statement by George Santayana may apply to such a forward-looking topic such as telecommunications convergence, an area where the newest and most advanced technologies ever developed are being applied to the integration of voice and data communications along with multimedia entertainment content into what is foreseen to be a single, seamless network.

Well, the reason is that I, for one, believe that the examination of past successes and failures in those areas targeted for convergence is essential to cross-check the convergence decisions that we currently are making and the paths to which we are committing ourselves. Being at the eve of a new calendar year, and, for those of us in the United States, at the dawn of a new administration which appears intent to play an active role in defining a new national telecommunication road map, a candid summation of where we stand right now coupled with a retrospective of how we got here in the first place seemed appropriate.

This is the first installment of what is planned to be a serial blog on telecommunications convergence with special focus on quality-of-service (QoS) issues for the various services that are to be supported. The need for a serial is obvious since convergence is a wide-ranging and complex topic that goes way beyond the confines of a lone article or single instance of a blog.

Among the questions that seemed worthwhile to be asked first may be the definition and range of the convergence itself, both in the context of the various network areas and with reference to the services targeted.

That is, does the upcoming ‘converged network’ include both WAN and LAN, or must a logical or artificial boundary still be defined to demarcate these two environments? In the case of the latter, is it really still possible to define such a boundary now that the cellular network, for example, is being extended inside our residences using femtocell-based LTE and/or WiMAX? It is quite apparent that the times when a simple network interface device (NID) separated clearly the network provider and the customer domains, and provided the foundation for a particular business model and operational environment are now long gone. Consequently, what will the new model look like and how will it be operated?

Still within the definition and range of convergence is the thorny issue of clock synchronization and distribution. Are there solutions being investigated that inherently address this issue, or is there an unspoken consensus that either a separate BITS network and/or GPS-based distributed clocks will always be required? Can we truly duplicate the performance achieved in the legacy PSTN or is the bar being lowered, instead, to fit whatever currently is seen as feasible over packet networks? If this is the case, what is the impact to the various services dependent on clock synchronization?

Do the technologies under consideration address adequately the support of the required services in both these areas? IP/MPLS and Carrier Ethernet appear to be the current front-running WAN technologies to support convergence. However, the extensibility of either protocol outside its native area of network origin may be fraught with risk, complexity and compromises.

Even more basic may be the original selection of the competing technologies themselves. Are the services currently envisioned really driving, in an impartial manner, the technical decisions, with of course an inevitable and reasonable amount of trade-offs included? Or are we primarily proceeding along philosophical, historical and financial lines of thought? In that same vein, it may be important to assess whether some MPLS derivative or Carrier Ethernet really offers sufficient QoS to support upcoming technologies such as LTE and WiMAX, as well as future-looking real-time services such as video calling. Similarly, do either one of these technologies offer sufficient inherent security to address all of private, business and governmental needs or will true security be a never-to-be-reached mirage always on the horizon?

On the retrospective side, are the past considerations that drove us to where we are at now still valid today, and, were all of the decisions made then to address these same considerations the correct ones? In particular, one may wonder what ever happened to ATM, one of our earlier convergence attempts. Did we learn from that lesson or are we happily and blindly threading a similar path again?

I believe this can be a fascinating voyage of discovery, and I am looking forward to you taking this trip with me in the future instances of this blog. With a little bit of luck, somewhere along the way we might be able to decide whether we are actually making history or just reliving it.

Serge Fourcand is a principal engineer with Huawei Technologies USA. He is an accomplished product manager and system architect with extensive multimedia experience in both consumer and telecom industry segments, including end-consumer multimedia products and associated controls, advanced multimedia distribution, speech processing, IP-based video and audio transport, digital signal processing, Ethernet Layer 2 transport and switching, and end-to-end telecommunications technology. Prior to Huawei, Fourcand worked as a product manager for AMX Corp., senior hardware architect at Metro-Optix, a system architect for Broadband Gateways and Alcatel USA’s Switch Products Division, and has been a member of the technical staff of Siemens AG in Munich, Germany.