Bottleneck Blowout

People often forget about the true purpose of technology: to solve old problems in a new, economical way.

It sounds kind of silly or obvious, yes. But not as many folks pay attention to this as you think. Remember MEMS – those tiny tilting mirrors? MEMS-based optical switches were supposed to replace those klodgy old electronic crossconnects (see Optical Crossconnects). No dice – MEMS was simply too expensive to manufacture, and the next generation of electronic switches packed more features and bandwidth into a smaller price tag. MEMS technology was impressive, yes, but it didn't yet have the economical edge. (It turns out that MEMS is now finding other applications, including for HDTV projectors – but that's another story.)

Today's big problems in the telecom industry? Access bottlenecks, old copper wiring, and a lack of funds.

Enter next-generation DSL, including ADSL2+ and VDSL. These technologies are starting to grab the attention of the service provider community because they provide more bandwidth over the same old smelly copper wire. Service providers love mature technologies that are faster and cheaper than the expensive alternatives – especially when they solve big problems.

The current Light Reading InsiderNext-Gen DSL Deluge – examines the arrival of next-generation DSL technologies such as ADSL2+ and VDSL. We interviewed dozens of service providers and asked them what they intend to do with higher-speed (upwards of 20 Mbit/s) DSL. It turns out that the economics are such that it can support most of the forthcoming broadband applications – including IP video – that carriers would like to offer, providing the foundation for the next round of broadband deployments.

The DSL story has always been one about bucking expectations, and this time isn't any different. When DSL emerged in the mid-nineties, we (including yours truly) scoffed at it because of its ridiculous limitations in reach and its pathetic need for spotlessly clean wiring. Well, the engineers worked on that. Then when PON and FTTP popped up in recent years, everybody was prepared to write off DSL as a dead-end technology: broadband for geezers. But here it comes again, with another generation that can ramp as high as 100 Mbit/s.

The main problem for FTTP – and thus the advantage of DSL – is that new fiber access networks still require the service providers to dig long, expensive trenches through Aunt Mamie's petunias (let's call it the COTP, or the "Cost of Trenching Petunias"). Operators are allergic to anything that requires large numbers of trucks, machinery, and humans. In the next few years, it's hard to envision a way to engineer out this cost. DSL, on the other hand, uses copper wiring – long since installed and amortized out of their network cost. Let's face it: It's much easier for service providers to upgrade your bandwidth by sending you a new $100 CPE device and transmitting some software over that old copper wire than it is for them to send a crew of union workers out to the neighborhood (see Fiber's Sticky Wicket).

You see this over and over again in technology – just as one impressive, young star gets all the ink, the old geezer technology makes a comeback with a refurbished look. It's like Kurt Warner stealing Eli Manning's thunder. After all those years of abuse, he's still got a few touchdowns left in him.

Here we are in 2004, and DSL is not only alive and well, but it appears to be hitting its stride. The reason? The same reasons it took hold – the engineers have succeeded in improving the economics by stretching out the reach and adding more speed. It's become a mature and economical technology, just right for the times.

The end result: It looks like Eli Manning may have to sit on the bench for another couple of years.

— R. Scott Raynovich, US Editor, Light Reading

This report, Next-Gen DSL Deluge, is available as part of an annual subscription (12 monthly issues) to Light Reading Insider, priced at $1,350. Individual reports are available for $900.

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paolo.franzoi 12/5/2012 | 1:16:40 AM
re: Bottleneck Blowout
I posted this in another thread but for real take a look at the Calix website in the area for the ADSL2+ and look at the performance with SELF FEXT.

Guess what this affect is real and has been noted at the DSL Forum in Prague. In fact testing for this (not just the Self NEXT) issue will become part of the ADSL2+ Interoperability test.

Guess what here is the good part. It impacts the new frequency bins more (that is why its less of an impact in ADSL). Which is really good news for things like VDSL2.

Its also why ADSL2+ Bonding is such a hot topic right now.

God I love it when analysts are playing catchup to the technology.

JoeBagadonuts 12/5/2012 | 1:16:39 AM
re: Bottleneck Blowout 2 columns and press release on the same report in 2 days???? I think there is a bit of overkill on this topic.

Scott Raynovich 12/5/2012 | 1:16:35 AM
re: Bottleneck Blowout Can you post in English? Then I might be able to respond.
paolo.franzoi 12/5/2012 | 1:16:34 AM
re: Bottleneck Blowout
Yes, first Scott get an engineering degree then you might understand.

Second, go to the Calix website.

Third, note that once you have about 5 - 6 DSL lines in a binder group that 15 Mb/s is max beyond 1kft or so.

Reading is good.

Scott Raynovich 12/5/2012 | 1:16:33 AM
re: Bottleneck Blowout >Third, note that once you have about 5 - 6 DSL ?>lines in a binder group that 15 Mb/s is max >beyond 1kft or so.

That is interesting. I will check it out. Not sure it changes the general DSL vs. FTTP argument though. There have been worse engineering problems that have been overcome.
paolo.franzoi 12/5/2012 | 1:16:32 AM
re: Bottleneck Blowout
It changes the argument dramatically. Your words are yeah I will have lots of high rate DSL at nice long loop reaches. This is how to avoid construction (i.e. 25Mb/s at 5kft is a pipedream in the real world, 12Mb/s at 5kft is more realistic). Well guess what, without lots of construction you will not. At that point, lots of construction and get DSL or lots of construction and get fiber.

Your presumption is that this is a glitch. Its not. Its physics.

So, what does this mean. Its a time versus money tradeoff. To be most efficient on money, you would like to put in as much fiber as is humanly possible as soon as possible. This will allow you to avoid the cost of building the network again. Because you will build it again.

In fact to remain competitive, you may need to start the rebuild before you finish this build. Depending on what cable does for answering this high bandwidth DSL story. Remember they can bump up their network bandwidth by adding equipment while you are doing construction.

Scott Raynovich 12/5/2012 | 1:16:31 AM
re: Bottleneck Blowout >It changes the argument dramatically. Your >words are yeah I will have lots of high rate >DSL at nice long loop reaches. This is how to >avoid construction (i.e. 25Mb/s at 5kft is a >pipedream in the real world, 12Mb/s at 5kft is >more realistic).


Do you work for AFC? What's going on with that deal with Verizon?

Seriously, your points are well taken. Good feedback. When you say, "12Mb/s at 5kft is more realistic," though, that doesn't really change my opinion. The fiber thing will come, it will just be slow, and it will take time. DSL has plenty of life left in it. If you sent me 12 Mb/s today, I'd be overjoyed.

paolo.franzoi 12/5/2012 | 1:16:30 AM
re: Bottleneck Blowout
You might be, but ask the carriers how much bandwidth they think is required for them to make a viable service.

chook0 12/5/2012 | 1:16:26 AM
re: Bottleneck Blowout You might be, but ask the carriers how much bandwidth they think is required for them to make a viable service.


At the same time you have to ask them where they are going to get the money to pay for trenching through Auntie Hattie's tulips. And how they are going to get an ROI on that investment out of the incremental improvement from 15Mbps to 100 Mbps (or 1Gbps) to Auntie Hattie.

It ain't physics, it's economics and finance.

I think the key lies in carriers being able to tap into the revenue flow to content providers and e-commerce companies that is currently bypassing them entirely.

But that's a different flame and I don't want to light it here and now. :-)

chook0 12/5/2012 | 1:16:26 AM
re: Bottleneck Blowout Your presumption is that this is a glitch. Its not. Its physics.

Not that I am one of the believers that DSL is going to save the world (in fact I am firmly in the camp that says we'll have to string fibre sooner or later), but I'be burned lots of times with the "it's not a glitch it's physics" thing.

Remember when Cat5 was 25MHz max BW, and people were saying it was good for 25Mbps over 100m? Not so long ago, right? At the time I said it was physics, not a glitch.

But of course it is only 25Mbps if you are using something like Manchester encoding or 4B5B encoding. (baseband encoding). Didn't take people long to realise that in the 90s we had enough processing capability on chips to have multiple bit-per-symbol codes and go into high-speed phase and amplitude modulation schemes. Enter CAP-M (correct me if I've got the name wrong) which had in excess of 6 bits per symbol and allowed 155 Mbps over Cat5.

And at the same time people were improving Cat5 to have up to 100 Mbps BW and lower NEXT, etc etc.

So yes, in this world we are subject to basic physical laws. (In this case Shannon's Law) but we need to look closely to see if we are hard up against the physical law or actually against an engineering limitation that (temporarily) is stopping us from getting closer to the physical limits. It's often the latter even though people are assuming it is the former.

Next candidate for this: Radio spectrum. Some people say that with Software defined Radios (SDR) we can design transceivers that browse the spectrum from DC to light and there will be no need to have spectrum allocation anymore. And no need for fixed lines, at least in the access.

I say: If you do this, what you'll do is raise the noise floor and have a tragedy of the commons because electromagnetic spectrum is actually a finite resource and however you cut it there is not enough for all the demands that people would make if it were free and technology to use it were cheap. It's not a glitch, it's physics.

They say: We'll design the radios to be spread-spectrum and whisper underneath all of the other stuff.

I say: every whisper is additive noise and if a million people are doing it then it adds up to a shout.

Who will be right?

Hint: I have been wrong before. (but naturally think this time is different. :-))

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