Translation Please: A Modular-Techno Parable


Once upon a time, there lived two brothers. Each loved and respected the other, yet each took great joy in wanting to do things better, faster or cheaper than his sibling.

The brothers lived beside each other, on large farms of nearly equal sizes, growing wheat. The first brother, Charlie, shipped his wheat to market by train — and felt his brother Tom mad for shipping his wheat by truck. That feeling was mutual.

One day, the two brothers — who were friends — realized that they were spending way too much time debating which shipping method was better, faster or cheaper. Times were changing. Maybe it was time to go the route of efficiency and share lines.

Plus, Charlie was readying to expand into corn, in a big way, and didn’t want to disrupt his anticipated workflow any further than it already would be. Ditto for Tom, who was doubling up on wheat.

Luckily for you, this allegory can only go so far — but what it attempts to describe is the recently announced move by CableLabs to issue a set of common interfaces for converged services, under the umbrella name “Modular Headend Architecture.”

Translation: It’s a way to (finally) make interoperable the ongoing work on edge QAMs by the VOD, switched digital video and DOCSIS supplier communities.

To quote the CableLabs press release: “The specifications provide a point of harmonization between the Time Warner Cable-led Interactive Services Architecture (ISA) and the Comcast-led Next Generation On Demand (NGOD) architecture, which are used throughout the industry.”

(“Used throughout the industry” is code for the fact that all other operators — Charter Communications, Cox Communications and everyone else — generally rely on what Comcast and Time Warner Cable cook up with the supplier community.)


So, in this allegory, Charlie is Comcast, and his expansion crop of corn is DOCSIS 3.0. Tom is Time Warner Cable. His additional wheat crop is switched digital video and its offshoots (Start Over, Look Back, etc.).

The train, then, is NGOD, and the trucks ISA.

The parable’s realization — that debating over the better shipping method is wasteful — is today’s engineering realization that all operators could be spending less money on QAMs, which are purchased in great quantities.

The last time this column checked in on ISA was in July of 2001. Back then, ISA was defined as “the language all servers should speak, when they speak to one another.” Time Warner discovered this need as a direct outgrowth of its Full Service Network experiments in Orlando, Fla., in the early ’90s.

At the time, the work was predictably video-centric (cable modems were infants at the time). ISA covered how to provision (set up customers) and bill for a multiplicity of different interactive-TV applications, without getting bogged down in the goo of the back office.

Comcast’s NGOD came a few years later. It, too, arose from the video side of the house, and specifically VOD. As consumer demand for it grew, so grew the need for video QAMs — but at the same time, QAM usage for DOCSIS was growing at a steady clip, too.

Part of NGOD (a huge specification) defined how to use QAMs across service silos, and specifically how to use a thing called an “edge resource manager” — picture it as a sort of router for QAMs.

Ditto for Time Warner, except it called its work “GSRM,” for “Global Session Resource Manager.” It included a protocol from ISA — the “session-setup protocol” — which told video QAMs which sessions should be created on which output ports, and which program channels.

As you can see, this dissolves into details fairly quickly. Suffice it to say that each operator’s supplier community got busy building ways to manage QAM resources more efficiently. But because there were two different ways to go about it, there arose a bifurcated QAM marketplace.

Up until now, the work of making a universal edge QAM was fairly contained to sharing QAMs across VOD and switched digital video traffic. That’s true of all MSOs.

With the CableLabs MHA specification, that focus expands to be able to share QAMs across all types of digital traffic, be it SDV, VOD or DOCSIS. And it does so in a way that can be adopted by all QAM suppliers, whether they hail from the SDV, VOD or broadband/IP sections of the business.

That way, Charlie and Tom can grow whatever they want, and move it to market in a better, faster, less costly way.

Everybody wins.

Stumped by gibberish? Visit Leslie Ellis