spacer 2Telebyte Gfast Testing Guide 320

gfast map nov

Dark Green: Firm commitments from incumbent: BT (10M), Belgacom, Australian NBN, Swisscom,  Austria, Bezeq Israel, Chunghwa Taiwan, Telus Canada, Telekom South Africa, SK Korea, (U.S.) AT&T, Century, Frontier, Windstream, Belgium, Omantel

Mid Pink: Smaller carriers in Germany, Norway, Finland, Japan

Light Green: Incumbent likely:  France, Germany, Italy

Sckipio 35b and G.fast 350More than a year late but now in acceptance trials at a large European carrier. 8/16 Everything in the article is accurate as far as I know, except the claim "First results" in the title, now removed. A reader just informed me that Fastweb in Italy is actually in production with 35b and there are some results ion Italian websites 8/20 I thought I had "First results" but in fact Alcatel had published results from KPN testing I had missed. Below.

Original: From chipmaker Broadcom to Nokia and Huawei, everyone promised 35b "Supervectoring" for about a year ago.

Now it's here, and Kevin Schneider’s lab tests at Adtran found “mid to high 200’s @ 1,000 feet.”  Talking with Kevin, I didn't sense any major anomalies in his testing at other distances.  Until now, 35b speeds were estimated based on simulations like the chart here. These early test results are very encouraging. The hope is they can move to field trials in Q4 and soon after to deployment.

35b is essentially vectored VDSL 17b MHz extended to 35 MHz. Initially, the industry thought G.fast from close-in distribution points would be the standard upgrade. With volume production and some competition, the price of G.fast equipment will fall to very little more than VDSL. 35b is close to G.fast speeds from around 300 meters to around 450 meters, but much slower for shorter distances.

The savings won't come from a big difference in modem and DSLAM prices down the road. Moore's Law continues to bring chip prices down while performance increases. However, DT won't have to replace millions of 17b modems because 17b and 35b can co-exist in the same binder. Questions remain about vectoring efficiency, especially with older modems, so everyone is anxious to get field results.

When Deutsche Telecom and British Telecom costed out running fiber to the millions of distribution points, they changed plans. BT decided to use G.fast from the existing cabinets, KPN 35b datadropping speeds for many from close to a gigabit to a few hundred megabits. Homes close to the cabinet will get 500-800 megabits, but BT will not run new fiber closer to homes. DT's CTO said they would do G.fast in 2015 but the beancounters said no.  DT has been earning substantially less than they've been paying in dividends. The marketing miracle at T-Mobile U.S. is the only reason DT's CEO still has a job. 
 

Someone, perhaps at Alcatel, realized that DT wouldn't have to replace as many customer modems if they upgraded to a new system that could work with some of the older modems. That's not practical with G.fast, with a line code incompatible with the older modems. They decided to go with the modified VDSL, extended to 35 MHz. 35b sacrifices a great deal of speed but doesn't require replacing as many old modems. In addition, 35b is faster for those beyond the efficient reach of G.fast.  DT signed on, especially after Broadcom promised chips would be ready in 2015.

In theory, the 35b chips should have been an easy design modification, I was told, because they were so similar to the existing chips. If any reader knows what held them up for a year, please let me know. Anonymity assured. 8/20 Update Alcatel's Paul Spruyt's presentation last October said they had 8 trials already underway and four customers, I just noticed. Ten monthe later, I would have some of these to be in production if they hadn't found problems. <end update>

The U.S. and Europe mostly deploy VDSL using 17 MHz, not yet vectored. Many customers get less than 50 megabits downstream, although it's often advertised as "up to 100 megabits."  With vectoring, the Belgacom data is that most short loops see doubled speeds, with most over 80 megabits and many over 100. Belgacom, under heavy pressure from cable, has invested in many cabinets close to customers. DT, AT&T, and Century/Qwest have fewer cabinets, longer distances, and ultimately lower speeds.

17b runs from 2 MHz to 17 MHz; 35b runs from 2 MHz to 35 MHz. The former covers 15 MHz, the latter 33 MHz. That's a 120% increase in spectrum used, so 250 megabits to about 300 meters is plausible. We now have a confirming datapoint. Thank you Gary Bolton and Kevin Schneider for what I believe is the first reported test speed. Adtran in the last few years has gone from reserved with the press to being one of the most helpful companies.

The Site for gfast 230
 

G.fast News

I’m still working through remarkable presentations from the Broadband Forum events. Michael Weissman, Bernd Hesse and team did a remarkable job choosing the speakers. http://bit.ly/BBFBASE

Deutsche Telecom: 35b Supervectoring Delayed to 2019 http://bit.ly/35blater
Broadcom is now over 3 years late. DT briefed German reporters after their financial call and revealed 35b was now delayed until 2019. 35b should deliver 200+ meg downloads 500-600 meters, a crucial tool for DT, which is losing share to cable. Cable now covers about 70% of Germany and is expanding. DT now only offers 50-100 megabit DSL while cable is often 400 megabits, going to a gigabit. 

The problem is software; the hardware is shipping and supposedly will work. DT says 35b is not ready to turn on. Broadcom in 2015 said 35b was in "production" in the press release below. Alcatel in early 2016 said to expect complete systems very soon. "35g is very similar to 17a so there should be little delay."

Broadcom's problems are leading major telcos and vendors to have a plan B, using Sckipio G.fast. DT itself is planning extensive G.fast deployments in 2019, mostly in apartment buildings. http://bit.ly/35blater

Gigabit 100 Meters - Unless the Wires are Lousy http://bit.ly/gflousy
Speeds are fine, "Unless there's a line problem." I've been reporting for three years that ~10% of lines have problems. In the chart by Rami Verbin of Sckipio, he finds G.fast goes ~130 meters on good lines. Poor lines have about half the reach. 

His chart roughly matches the reports from Swisscom, Belgacom, and England for both G.fast & vectored DSL. The 10% with problems can cause the majority of the line-related complaints to support. The angry customers drive up cost.

Rami's solution to reach the gigabit is bonding, supported on the Sckipio chips. Verbin made some additional points:

  • 4 gigabits is possible by bonding two decent 2 gigabit lines.
  • Even in a service from remote cabinets, ~25% are close enough to get a full gigabit."
  • cDTA and iDTA are practical ways to deliver much higher upstream by switching some bandwidth from downstream to upstream only when needed.
  • 35B will probably be similar but Deutsche Telecom doesn't expect to deploy until 2019. http://bit.ly/gflousy

AT&T Wants Coax 2-5 Gigabit G.fast. Very Soon. http://bit.ly/ATTCoax
AT&T faces intense competition from cable, talking about 10 gigabits in both directions. (Cable will only be 1 gig down, ~100 meg up, until ~2021.) AT&T wants something to brag about as well.

AT&T gained millions of lines of coax as part of the DirecTV deal. Alcatel and Huawei are leading the development of G.mgfast. That uses 424 MHz, full duplex, to achieve ~2.5 gigabits in both directions. The reach on telco twisted pair is only about 30 meters. On coax, those speeds can probably extend far enough to service most apartment buildings. Using 848 MHz, speeds can reach 5 gigabits. The ITU standards group has been aiming for 2019-2020 for G.mgfast, too slow for AT&T's marketers. David Titus wants a high-speed standard for coax "early in 2018." He believes that is "doable."http://bit.ly/ATTCoax

Read more ...