Comcast, Time Warner Differ Over Cable Next-Gen Architecture

TORONTO -- The two largest cable operators, Comcast and Time Warner Cable, appear to be taking somewhat divergent paths on an ambitious next-generation architecture for the cable industry, frustrating the original goals of network designers, aggravating equipment vendors, and potentially driving up equipment production costs, officials said at the SCTE Canadian Summit.

In spite of efforts by the two operators to downplay any differences publicly, signs of some key technical distinctions between Time Warner’s proposed convergence edge project and a similar initiative promoted by Comcast emerged during the summit last week. Responding to a trade press report about the split, Comcast Chief Technology Officer Tony Werner conceded that Time Warner is seeking new network edge devices that are smaller and less dense than the ones that Comcast has been pursuing. But he declined to say any more until he talked to his TWC counterparts. “We prefer to see things of this nature be industry-wide,” said Werner, speaking on an industry leader panel. “Otherwise, it doesn’t do the cable industry any good.”

Comcast has been widely promoting its project, known as the Converged Multiservice Access Platform (CMAP), for more than a year. Under the CMAP initiative, cable engineers aim to merge the traditional functions of the cable modem termination system (CMTS) and the edge QAM modulator, which are now housed in separate devices, in one super-dense box. They argue that this approach will cut down significantly on required headend space, chop power and cooling costs, improve port densities, and generally make cable operations more efficient.

Ever since launching the initiative in late 2009, Comcast has enlisted many other major cable operators and organizations as partners, including Cox, Cablevision Systems, Charter, Rogers, Liberty Global, Cable Europe Labs, and National Cable Television Cooperative (NCTC) -- a consortium of smaller cable operators. Comcast has also signed up virtually all of the industry’s CMTS and edge QAM vendors, as well as such major router suppliers as Alcatel-Lucent and Juniper Networks. “We have had pretty good buy-in,” Werner said.

But Time Warner has been conspicuously missing from that list. Following up on persistent industry rumors, Light Reading Cable reported last week that Time Warner is separately pursuing its own next-gen edge device, known as Converged Edge Services Router (CESAR). Time Warner executives confirmed that, describing their proposed approach.

As Comcast and Time Warner officials have stressed in their public comments, the two next-gen architecture projects do share many of the same goals. For instance, the CMAP and CESAR initiatives both seek to produce super-dense headend devices that combine the traditional edge QAM and CMTS functions, thereby helping cable operators carry out the tricky migration to full IP video delivery.

However, the companies differ over some key technical aspects of their respective proposed architectures. For one thing, as Werner brought out in his panel appearance here, Time Warner is looking to deploy smaller, less-dense boxes than the ones that Comcast has in mind for cable systems with large headends and hubs. For another, the two appear to differ over integrating video encryption into their boxes.

Werner said he hopes Time Warner’s CESAR work will lead to “another profile of CMAP” for vendors to use. “As long as we can get pretty common on the strategy,” he said, there shouldn’t be too many problems. But other cable executives expressed concerns about the potential CMAP-CESAR divide. Speaking on the same panel as Werner, Dermot O'Carroll, Rogers senior vice president-access networks, said he hopes the two projects are similar enough that economic scale can be achieved: “It’s always better to have scale."

Equipment vendors fear they will end up having to make two entirely separate products for the two large operators. “Our goal is to come up with a single architecture that works for both,” said John Ulm, a staffer in the chief technology officer office at Motorola Mobility, speaking on a separate panel last week. “We are looking at the different features and hope it will be limited to software differences.”

Meanwhile, such other cable operators as Cox are already crafting plans for upgrading to the CMAP architecture without getting rid of their current CMTS and edge QAM devices. Jeff Finkelstein, senior director of network architecture for Cox, said on a panel his company is weighing a “CMAP-lite” approach. Under this approach, Cox would first replace its edge QAM functions with a downstream-only implementation of CMAP and then add the upstream components later. Finkelstein said Cox intends to start some “very limited lab trials” of CMAP-lite this summer.