Special Section: IP Backbone

Suggesting the strength and flexibility of the human vertebrae and the central nervous system that they enclose, telecommunications professionals have long used the term "backbone" to describe that part of the network that carries the most traffic and connects all local area networks. The cable pioneers who founded this industry certainly displayed lots of another kind of metaphorical "backbone"—guts, persistence, tenacity—but it was only in the 1990s, with the advent of high-speed data and waves of industry consolidation, that the cable equivalent of the telecom backbone emerged. Geographic extent and product portfolios continue to drive the definition of wide area networks that link an MSO’s systems and market areas. As Comcast VP of Network and Transport Engineering John Leddy reminds us in his interview, his company is in 35 states, plus D.C. But it’s not just Comcast. MediaCom Communications VP of IP Networks Joe Selvage, co-author of the lead article in this section, manages two backbone networks (northern and southern) that encompass ten states between them. As for services, high-speed data was arguably the initial driver in the build-out of cable’s regional and national backbones. But services have proliferated. Selvage tells us that across MediaCom’s converged IP/GigE/DWDM backbones run the following: VoIP, HSD, VOD, standard and high-def digital video, internal IT traffic, and enterprise services. That’s not an atypical mix. Supporting this kind of a portfolio, however, has required the cable industry to lean upon innovations in both the networking and the optical arenas (such as those outlined by OpVista CTO Winston Way in his sidebar). Insofar as cable is going where no previous telecom backbones have yet ventured, the industry also has needed to break new ground with vendors. That would explain, for instance, Comcast’s Open Transport Initiative, a noteworthy project that is likely to shape the next stage in cable’s evolving backbone networks.—CT