Who’s the Fastest in Broadband?
by Leslie Ellis // October 24 2005
One of the more palpable trends in the broadband Internet community is the leapfrog war between cable and telephone companies over connection speeds.
It’s most visible in the downstream direction, or in terms of how swiftly packets can be pumped into homes. In multi-Megabit chunks, the rate of speed available to a cable or DSL (digital subscriber line) modem tends to ascend regularly. It’s a current measure of competitive agility.
An active debate among broadband technologists, for instance, is whether a Moore’s Law parallel is brewing in bandwidth — where downstream speeds double every 18 months, while prices remain fairly static.
Apply that hypothesis to Cablevision Systems Corp., which offered a maximum downstream speed of 10 Megabits per second (Mbps) last October. That would mean rocketing to 20 Mbps next spring.
The speed war implications are vast. Is there a ceiling? Who’s best positioned to be fastest: cable or the telcos? If you’re a cable system manager, how do you budget to be the fastest guy in town next year — without squeezing a speed trigger that isn’t really necessary until ’07?
Tough call. Over the past nine years of broadband’s ascendancy into the consumer mainstream, one fact persists: No matter how much there is, people always find ways to consume more. Broadband is like fresh water. Or gasoline.
How To Do The Math
Figuring out theoretical maxes for varying broadband providers isn’t the easiest math in the world, but it isn’t astrophysics, either. This week’s translation will focus on how to do the “max speed” calculations for the cable side.
The amount of downstream speed available to customers of cable modems depends on two variables: Bandwidth allocation, and system architecture.
Say an operator allocates one 6-Megahertz digital channel to broadband Internet services. (Most do.) Say that operator is slinging data toward homes using a form of modulation known as 256-QAM (quadrature amplitude modulation). That’s equivalent to 38 Mbps of data traveling downstream, on that channel, toward homes.
This is where system architecture comes in. That high-speed channel travels from the headend to a “serving area group.” In general, a serving area is comprised of four, 500-home nodes, all of which are “sharing” the 38 Mbps available in that high-speed channel.
Let’s assume that 60% of the homes passed by that 2,000-home serving area group are cable customers. That’s 1,200 homes. Let’s further say that 40% of those homes use a cable modem for Internet access. We’re down to 480 homes, sharing the 38 Mbps of raw capacity on that broadband channel.
It’s tempting, but incorrect, to next divide 38 Mbps by 480 customers, to establish how much bandwidth people really get. In practice, people hardly ever partake in the Internet in the same exact way, at the same exact time.
You might be reading a Web page, while your neighbor is downloading a fat operating system patch. Two streets over, somebody’s teenager is clattering messages into a dozen different instant message windows. Each of you is using bandwidth differently.
Geography matters, too. College towns devour bandwidth. Retirement communities snack on it. That adds to the trickiness of the calculations.
Maintaining An Edge
Cable operators have three immediate options when it comes to retaining their position as “the fastest guy in town.” One is to revisit those serving area groups, to decouple them from the 38 Mbps spigot. Most operators do this in two steps: Unhook two of the four nodes sharing the channel, then the other two, as bandwidth needs dictate.
As resources go, disaggregating serving groups is a matter of buying “blades” for the headend portion of the broadband system, known as the cable-modem termination system (CMTS). Pricing varies predictably, but a safe estimate is $25,000 per blade, or around $12,000 per downstream port.
After that, a further option is to “split the node,” which really means adding lasers and receivers in such a way that 250 passings share the 38 Mbps, instead of 500. Split it again and that’s 125 homes.
The third option is to dedicate a second (or third, or fourth) channel to broadband Internet. That’s part of what DOCSIS (Data Over Cable Service Interface Specification) 3.0 is all about: Gluing four or more channels together, summing the throughput (38 Mbps x 4), blasting it down to individual modems.
In combination, those options (when carefully applied and in a rational market) will suffice to position the cable side as the “fastest guy in town.”
Next time: How to do the math on telco-delivered speed maximums.
This column originally appeared in the Broadband Week section of Multichannel News.
A Tribute to Roger Brown
by Leslie Ellis // October 10 2005
A black cloud continued to gloom over cable’s technical community last week, as we awaited the death of one of our cherished peers, Roger Brown, who runs sister publication CED Magazine as editorial director and publisher.
In mid-September, when many of us were in New York for activities surrounding the Walter Kaitz Foundation dinner, Roger and his family got terrifying news from his doctors: Cancer lacing through his liver; spleen triply enlarged.
This after being told, in July, that the week-long bio-chemotherapy treatments he endured earlier in the year had succeeded in killing the melanoma cells that were trying to kill him.
Outside of technical circles, Roger Brown is little known for his contributions to this industry. That’s why this week’s “translation” will focus on Roger, who is unquestionably the industry’s most gifted technology translator.
Losing him is like losing a supporting wall in our collective industrial house.
All of us who know and love Roger spent the past three weeks struggling beneath the weight of news. Near the end, Rog told me that he was approaching a place of calm. “It’s not my style to go out bitter,” he said. “It’s not who I am.”
Two weeks ago today, Roger and his wife of 22 years, Birdy, asked me to speak at his service. As my head exploded, I somehow simultaneously registered that Roger was planning his “last issue.” A macabre blessing, but a blessing nonetheless.
My job, along with my colleague and friend Rob Stuehrk, is to describe Roger’s impact on this industry. This, quite frankly, is a practice run.
Roger was a journalist first. He lived objectivity. He hated hyperbole, and struck it with pleasure from any stories slated to run in the magazine.
As a writer, he clarified without insulting, and wasn’t afraid to tackle controversy (technology contains big vats of it) or mind-twisting topics.
As a reporter, Roger was the master of the pause. When we’d do interviews together, I learned to let him take over towards the end. Usually it was some variation of “so what else is going on?” Then we’d shut up. Completely. The strain of the silence often invoked a juicy and unexpected nugget that alighted within the first two paragraphs of the resultant story.
As an editor, he was light-handed and fair.
Many Roger fans wrote to me last week that Roger is CED Magazine. He ran it for nearly two decades, and through eight corporate owners, always with that twinkly smile pouring out from page 4. Industry elder Joe Van Loan lauds Roger for being “like a sea anchor — he has a way of keeping us from whip-sawing around at every new thing to come along.”
The words describing Roger last week from his peers, colleagues, elders, and generally huge fan club were these: “Humble.” “Down-to-earth.” “Fair.” “Non-pretentious.” “Friendly.” “A beacon of candor in a dark room.” “Deliberate.” “Kind.” “Trustworthy.” “Remarkably accessible.”
That last one strikes a strong chord with those of us who work with Roger. He is that rarity in life who puts down his pen, turns away from the computer screen, ignores his phones, and focuses on YOU, when you enter his work area (press room, office, wherever.)
Inform Not Impress
“Within the pages of this technical magazine, Roger managed to reconcile the practical with the theoretical, and he managed to do so in a way that kept every reader’s interest,” said Dom Stasi, the chief technology officer for TVN Entertainment, and a friend of Roger’s. “He was out to inform, not to impress. That was his genius.”
Those of you who read this column regularly know that I’m reluctant to blather on about myself — a tenet I learned from Roger. Yet, in this case, I feel compelled to note that, in April, I dedicated my NCTA Vanguard Award to him.
In my acceptance remarks, Roger was the only individual I mentioned by name. I thanked him for teaching me not to be afraid of technology, and for introducing me to the technologists who take the time to describe things well. (I didn’t thank him for introducing me to an eclectic guy named Doug, who became my husband. But I could have, because he did.)
When Roger asked me to speak at his service, I asked him how he wanted to be remembered. He said he wanted to be remembered as someone who treated people as he wanted to be treated.
For me, that legacy started 15 years ago, when Roger and I were trolling new products at a trade show. We happened upon a new amplifier, and I asked an unnamed technology honcho, standing nearby, what was different about it. “Don’t worry your pretty little head about it,” the honcho said. “It just has lots of bells and whistles.”
Roger didn’t miss a beat. “Back off, (name of honcho),” he said. (With gusto.) He became my big brother that day, and stayed that way ever since.
It is a great honor to be Roger Brown’s “little sister,” at least in an industrial sense. It is also a role I plan to carry on, especially with so much of Roger’s sunny, steady spirit still thriving in his kids: Tony, (17); Cayleigh (14), Nick (12) and Allie (7).
It is highly unlikely that Roger will ever read this, or any of the “assignments” he gave us in the days before his death. That heightens the honor — but doesn’t do much to lift the black cloud of void.
Editor’s Note: Contributions to the Brown family can be made by check to the Roger Brown Family Account, care of First American State Bank, 8390 E. Crescent Parkway, Suite 100, Greenwood Village, CO 80111.