Comms chips

First-Mile Ethernet Makes DSL Choice

The group responsible for standardizing Ethernet in the first mile settled a dispute last week, deciding to use G.SHDSL as the DSL standard for copper.

Not a major breakthrough, perhaps. But it does put to rest some controversy that had emerged in November, when G.SHDSL and asymmetric DSL (ADSL) camps squared off (see 'First Mile' Ethernet Hits Snags). The matter was settled during last week's Institute of Electrical and Electronics Engineers Inc. (IEEE) meetings in Vancouver.

Ethernet in the first mile is being standardized by the 802.3ah task force within the IEEE. A subset of the standard involves options for delivering Ethernet over copper in the first mile. ("First mile" is the same thing as "last mile" and was changed for marketing reasons. Basically, it refers to the portion of the telecom network that directly connects data or voice services to end users.)

The copper committee had already decided to standardize on very-high bit-rate DSL (VDSL) for connections of 2,700 meters or less. But for longer connections, it became a tossup between G.SHDSLG, a version of DSL created within the International Telecommunication Union (ITU), and what's called ADSL Annex J, an enhanced version of ADSL (see First-Mile Ethernet Camps Dig In).

G.SHDSL was supported by RBOCs and was likely to be accepted into the standard regardless. The camp supporting ADSL was holding out hope that the standard would include both types of DSL, but there was some suspicion that that wouldn't jibe with IEEE rules. In the end, G.SHDSL took the prize alone.

"Annex J isn't fully available yet, and that was part of the decision," says Behrooz Rezvani, CTO of Ikanos Communications Inc.

Ikanos was an ADSL backer in this argument, but Rezvani says he's fine with the choice the task force made.

"It's positive that the committee made the decision," Rezvani says, although he adds, "We think a bigger market potential can be reached by including other DSL types.”

Ikanos officials say VDSL is where the Ethernet-DSL action is going to be anyway. G.SHDSL is relatively slow, maxing out around 2.3 Mbit/s. VDSL, by contrast, runs at 26 Mbit/s -- split symmetrically or not, depending on which version you're using -- and Ikanos officials say they've gotten the speed up to 50 Mbit/s, or 25 Mbit/s in each direction, with their proprietary technology.

"When you say 'Ethernet,' the first number that comes to everybody's mind is 10 Mbit/s. So, VDSL is going to be the dominant deployment for [Ethernet in the first mile]," Rezvani says.

— Craig Matsumoto, Senior Editor, Light Reading

photonsu 12/5/2012 | 12:51:55 AM
re: First-Mile Ethernet Makes DSL Choice Don't the copperheads have their own website newspaper?
Must they always barge in where unwanted?
Explain to me how they fit in with regard to HDTV delivery? Other future services?
Remember when Ethernet ran at 3Mb/s?
Do we really want to go backwards?
What's the point of being a techie in the optics field if we are to be continually shackeled in copper chains?
Dark day for Photonsu!
beowulf888 12/5/2012 | 12:51:52 AM
re: First-Mile Ethernet Makes DSL Choice Photonsu:
Careful, with a posting like that, you'll start a flame war with copperheads. And you know how well copper conducts heat (unfortunately it's a bit resistant to data than glass is). Worse yet, the radioheads are liable to start whining that you dissed them by ignoring their favorite medium. Jeez! How 'bout a little more diplomacy on your part?! I mean, even if they are ignorant savages, you need to respect their superstitions ;-)

Tongue firmly in cheek...
strands555 12/5/2012 | 12:51:49 AM
re: First-Mile Ethernet Makes DSL Choice There is a lot more at stake here than just the RBOCs preserving their legacy. Thousands of Paleontologists--who refer to themselves as "DSL Engineers"--have devoted their careers to preserving the fossilized ruins of the copper empires of the past.

They aren't about to just give up their stature and notoriety among museum curators and Heritage Foundations. They are just as much to blame for broadband being a microscopic subset of what it could be, as the owners of the fossilized ruins.

After all, if all these Paleontologists ceased to exist, RBOCs would have no choice but to deploy fiber all the way. So let's assign a share of the blame for being stuck in the past to these self-important Paleontologists for aiding and abetting the RBOC agenda.
beetlejuice 12/5/2012 | 12:51:46 AM
re: First-Mile Ethernet Makes DSL Choice Bells labs has research in the area of transmitting photons across copper. They have internally reported in making progress in this area !
metroshark 12/5/2012 | 12:51:44 AM
re: First-Mile Ethernet Makes DSL Choice It is true that you can push much higher data rates over fiber, and these days, the equipment that needs to be installed on either sides of a fiber access connection can actually be cheaper than the equipment that would be necessary to achieve similar data rates (if at all possible) using copper.

However, there are more than 100 million copper pairs already installed in the US, and probably close to a billion througout the world. Replacing all these existing copper wires with fiber is probably going to take tens of years if not more. Until then, any technology that can extract more juice out of the existing copper infrastucture would be the only economically feasible solution. ( Of course, wireless is another story)

By the way, the new VDSL variants can achieve bit rates of over 20Mb/s over relatively short distances (2000 feet) and new ADSL/SDSL technologies can achieve 6Mb/s or higher over longer distances. These numbers are pretty critical. You can transmit a very high (DVD) quality MPEG2 stream over a 6Mb/s link. Most digital cable or DBS providers are using 3Mb/s or less for their "crytsal clear" digital channels. Using new compression technologies like MPEG2, it may be possible to achieve DVD quality with 2Mb/s or less. And higher bit rate technologies like VDSL can even be used to transmit HDTV streams.

Fiber is cool, but copper is everywhere.
BobbyMax 12/5/2012 | 12:51:37 AM
re: First-Mile Ethernet Makes DSL Choice Unfortunately there are number opf possibilities in this area: ATM over DSL, Ethernet over DSL, Frame Relay over DSL, Metro over DSL, Video over DSL, ADSL over DSL. The list goes on. It appears that there may be at least 1000 VC funding to exp[lore anything over DSL to explore commercial deployment. These possibilities are scary and it can give anothewr opening to "enterpreneures" to thrive on. What a tragedy!
opticalweenie 12/5/2012 | 12:51:35 AM
re: First-Mile Ethernet Makes DSL Choice Beetlejuice,
Could you explain to me the new physics that
describes how an electromagnetic wave can be propagated through a totally conducting medium (which is what copper wire is) over a distance oh, say longer than 1 or 2 nanometers.

Do you really think the Bell Lab gurus have discovered a way to shoot photons down a copper wire? If so, I have some nice swampland in Florida I would like to sell you.

metroshark 12/5/2012 | 12:51:34 AM
re: First-Mile Ethernet Makes DSL Choice Any one of the XXX over YYY combinations mentioned in your message would probably be better than the current situation: PPP over Ethernet over ATM (and sometimes over L2TP)

Ethernet over some form of DSL is probably the reasonable technical solution. It would be interesting to see if the US RBOCs will be willing to change from the inefficient DSL transport and subscriber management scheme they currently have to something better.
butternoparsnips 12/5/2012 | 12:51:04 AM
re: First-Mile Ethernet Makes DSL Choice Thank you metroshark. I was beginning to think I was going to have to explain to the lightheaded dimwits that existing physical plant does make a slight difference in the evaluation of feasibility of these issues. But you did it far more elegantly and calmly than I would have been able to. I owe you one.

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