Broadband Then and Now


Thirteen years ago tomorrow (Sept. 10, 2000), this column debuted with a long look at cable modem vs. telco DSL (digital subscriber line) speeds. At the time, 2.3 million people in the U.S. subscribed to cable high-speed Internet service, and 750,000 to DSL.

Today, and depending on whose numbers you like, cable counts 46.8 million (18 times growth), and telco DSL 34.6 million (46 times growth.)

Back then, telcos like Pacific Bell aired (very funny!) advertisements featuring the once-neighborly people of Laurel Lane, at war because cable’s shared bandwidth was slowing down their Internet connections. One guy dips his weed whacker over the fence, beheading his neighbor’s zinnias. Another pops a little kid’s balloon with a gardening tool. The postman shows a can of mace: “I used to use this just for dogs.”

The tag line: “Don’t share a cable line. Get Pacific Bell DSL.”

That first-ever column pointed out that DSL is also shared bandwidth, and that the technology would likely run into other problems as penetration rose, such as “crosstalk.” That’s what happens when the twisted-pair wires that telcos use radiate RF (radio frequency) energy from one to the next, because they’re so physically close to one another in the sheath. Symptom: Sluggishness.

DSL technology progressed, of course. From “ADSL” (asymmetrical DSL) there came “VDSL” (for very high speed DSL). Then there was “pair bonding,” which aggregates the bandwidth in homes with two phone lines.

The latest new-new thing in DSL advancement goes variously by “vectoring” and “vectoring with bonding.” Here’s an example of how people talk about it, from a recent batch of notes: “They’re offering 50 to 80 Mbps down, with vectoring.”

Guess what vectoring does? Hello again, crosstalk! Vectoring cancels it, which boosts downstream DSL speeds to a theoretical max of 150 Mbps downstream, and 50 Mbps upstream. (See above quote for a more realistic speed assessment.) With vectoring and a bonded pair: 300 down, 100 up.

Cable’s broadband technology progression came mostly through the DOCSIS (Data Over Cable Service Interface Specification) chapters — 1.0, 1.1, 2.0, 3.0. Coming soon, the whopper, DOCSIS 3.1, which puts operators on a comfortable path toward offering multi-Gigabit per second speeds.

Both types of networks still “share” bandwidth, although that’s changed, too. For the longest time, the cable “node” served about 500 homes. These days, “node splitting” is a routine activity in cable plant. It takes about a half a day, and, if enough “dark fibers” are present at the node, it cuts the number of homes sharing bandwidth to 125 or less.

So now, as it was back then, the supposed big bummer of cable’s shared bandwidth isn’t really that big of a bummer after all. And telcos will remain bandwidth-hobbled, but rallying hard, until they draw fiber right to the side of the house.

Meanwhile. Someone should find the creators of that Pac Bell ad and engage them on some new broadband material. Everybody needs a little for-real funny from time to time, even when it’s directed right at you.

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