spacer 2Telebyte Gfast Testing Guide 320

Gfast map July 2017

Dark blue: 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

Light blue: Smaller carriers in Germany, Norway, Finland, Japan

Green: Incumbent likely:  France, Germany, & Poland  

G.fast uses 106 MHz compared to only 1 MHz for ADSL. More MHz means more capacity but only works over very short loops. The actual ITU standard is 300 pages with dozens (?hundreds) of features which have relatively little impact on the speed. Traditional VDSL used 17 MHz for speeds around 100 megabits. G.fast can use 106 MHz for speeds typically 400-700 down, 100 megabits up. (The "gigabit" is pr fluff today although upgrades to actually get a gigabit are in the works.)

The distance limit: High frequencies used by G.fast don't go very far in ordinary telco twisted pair cables. It was designed for 50-150 meters and speeds drop rapidly after that. British Telecom and AT&T engineers told the ITU standards group that short reach was fine and G.fast nodes would be 8-16 homes. That set the standard. 

G,halffast When British Telecom realized the cost of running fiber to 4M "distribution points/curbs" they sent the entire plan back to the drawing board. The maximum wire length was increased from 250 meters to 500 meters. Chip makers are scrambling to modify their chips to the new demand. Many English homes will get speeds of 100-400 down, not close to the promised gigabit but pretty darn good.

How many homes get 400-700 megabits down and how many don't get 100 megabits depends on how much money BT decides to spend on the network. The odds are BT will keep costs down, leaving many customers with far lower speeds than the pr is suggesting. AT&T customers will probably get the 400-700 megabits down. Most of their deployment will be fiber to the basement and G.fast to an apartment. That's often less than 100 meters and the high speeds are possible. From now to at least 2019, AT&T plans to "fiber" ~15% of their homes. Most will be apartments.

"The Brits love their gardens," I'm told. They have very few apartment buildings, so BT can't use AT&T's strategy. BT is also planning to do far more than AT&T's 15%, going quickly to "nearly all the country." They will mostly have to deal with private homes. 

Yes, the gigabit is possible in a few years. Rami Verbin of Sckipio is confident a gigabit is practical. Based on testing the current generation of chips, he can increase the "constellation," loading more bits per hertz. "Non-linear precoding" should add more bandwidth as well, making the system more efficient. It increases the complexity of the chip but Moore's Law is bringing down the cost. Paul Spruyt of Alcatel has a similar expectation and these changes are being actively considered in standards. 

There's lots more to know if you're building a network, but this should get the non-expert started.

 

The Site for gfast 230
 

G.fast News
A remarkable 400 people attended the very strong Broadband Forum BASE events in Berlin and Las Vegas. Trevor confirmed BT would pass the million this year. Cioffi projected “Waveguide DSL” could carry 10 gigabits a kilometer as well as a terabit 100 meters. Werner sees a 4X improvement in upstream with cDTA. Much more in next issue.

Deutsche Wants a Gigabit, Finally Realizes 50 Meg Isn't Enough http://bit.ly/2zeZ5oZ
Deutsche Telekom is finally realizing that 50 megabit DSL won't make it against gigabit cable. VP Franz Seiser is blunt. "We must change radically, become disruptive and, above all, throw away things," he proclaims at BBWF. After years of DT insisting 50 megabits is plenty, we now hear "it is about Gigabit products" from DT's Robert Soukup.  
    A lucky building in Frankfurt will receive 500+ megabit service as ultra-conservative Deutsche Telekom experiments with G.fast. Soukup told BBWF, "We're going to have a field test in Frankfurt with G.fast and Fiber To The Building (FTTB.) We will know by the end of the year if this is the right way to go." Hint to Soukup: Yes it is. G.fast is working well at a dozen telcos I;ve talked to.
     The details are surprising. DT is going for CORD, Open Source, Calix, and Radisys. http://bit.ly/2zeZ5oZ

*** The new Telebyte Guide to Testing Gfast follows the Broadband Forum IR-337 Gfast test specification, the same used by the University of New Hampshire (UNH-IOL) for Gfast certification testing. Free download http://bit.ly/telebyte (ad) It is the best technical guide to G.fast  I have seen. Grab it. Dave

1.6 Gig in Sckipio-Calix Test http://bit.ly/Calix16
A telco tells me they are getting impressive early results from the Calix 48 port DSLAM with the new Sckipio 212 MHz chips. There still is work to do but this is encouraging. 
    Carriers want DSLAMs with more than 16 ports to reduce the deployment costs from the basement or larger field cabinets. Speed matters to the marketing side of the company; AT&T's CEO believes he must offer a true gigabit to match cable. (They've been getting ~750 megabits with first generation chips. http://bit.ly/Calix16

*** Self-Healing Wi-Fi With ASSIA Real-Q 
Beyond-the-Box visibility and control extends quality-of-experience (QoE) beyond the gateway to the end-user device for every device in the home. Based on ASSIA technology, proven across 80 million subscribers http://bit.ly/2dj7FJk (ad)

Reverse Power 4 Port DSLAM for Australia http://bit.ly/NetcommRP
Australia is connecting 1M homes to G.fast, some with a Netcomm distribution point mini-DSLAM. It's a small unit designed for pole or pit mounting. It's waterproof, pressure proof, and temperature resistant. Their matching home modem is bittorrent friendly, with two USB ports for a hard drive dedicated to sharing.
     A reverse power unit at the customer, the NDD-0100-01, can save the cost of bringing power to the DSLAM. They don't expect many orders until the second half of 2018, as nbn is waiting for the second generation chips. Netcomm demonstrated RP with BT Openreach in August. http://bit.ly/NetcommRP

*** Sckipio's Three advances are taking G.fast to the next level.http://bit.ly/Sckipio (ad)

Australia Makes it Official: G.fast to Million Plus http://bit.ly/GFAussie
No news here. In September, 2015, I reported Australia's nbn Going G.fast. This June. I reported the million home fiber to the curb (kerb?) was beginning. Unfortunately, they are no closer to figuring out where to find the needed $10B to $20B to cover the cost overruns. Instead, the parties are battling in Parliament about who is to blame. http://bit.ly/GFAussie

2 Bonded 212 Lines = 3 Gigabitshttp://bit.ly/twobonded
Sckipio at BBWF is demonstrating 3 gigabits down, nearly a gigabit up, over two phone lines, bonded. Twice the bandwidth (212 MHz instead of 106 MHz) times two lines is fast. Sckipio does great demos; at CES, they showed G.fast first generation chips delivering almost 1 gig upstream.
    “Sckipio is pushing Gfast to astonishing speeds with production silicon,” CEO David Baum proclaims. Calix is using the SCK23000 chipset in their 48 port gig+ DSLAM at the show. http://bit.ly/twobonded

Read more ...