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New Look at ADSL2
genrader writes "broadbandreports.com just posted a news article which had an interesting story about the new ADSL2, which should be approved in 2003. They say it should be backward compatible with current hardware. It seems pretty interesting. ISP-Planet has the featured in-depth look at it, so you might want to see if it is of any intrest to you."
Its great to see the old relic from the 50's, the Adsl, making a comeback. The Adsl2 - now with even more obscure parts!
siliconghetto
60623.
Sure, ADSL2 is faster, but how many of us are running our DSL lines at close to the max speed now? I can do 3+ Mb/s on this line, but only get to use 640 Kb/s. New technology that allows me to go faster, yeah that'll come in handy! If it worked at a much longer range it might be useful for some who are out of range now, but it really isn't much of an advance there either. So why should we care, this is like getting excited because Macs are shipping with a gigabit ethernet port when your office is running on a shared 10 mbit hub!
I'd like to see you consistantly download at 400+ kiloBYTES per second on your $40 CDN/month DSL connection.
I very nearly worship Shaw Cable.
Will Telco's be rolling out more and more central offices or remote dslams? Not a lot of people live within 8000 feet. Just more broadband solutions that aren't going to be available everywhere.
The increases in performance and range are pretty minimal. An additional 50kbps and 600ft of range isn't all that impressive, although the fact that it is backwards compatible with some existing hardware is semi-promising.
c le.asp?ID=5435
Anyway, here's some extra info on ADSL2, or G.bis that i dug up:
http://www.aware.com/products/DSL/gbisadsl2.htm
http://www.convergedigest.com/Silicon/siliconarti
http://www.dslprime.com/a/adsl21.pdf(sorry about the pdf)
Great one more thing for the telcos to screw up. I'm sure that ADSL2 means 2x the wait and 2x the cost. I'm already looking at my calendar and setting aside a week to wait for them to show up. I'm sure they'll have to make twice as many trips out for line tests and the techs will be twice as ignorant of the technology involved. In Soviet Russia, I bet they get it installed quicker.
Look - new, faster stuff that won't be available in my neighborhood!
The result is a far greater flexibility with downstream data rates:
20 Mbps on 2 bonded pairs
30 Mbps on 3 bonded pairs
40 Mbps on 4 bonded pairs
So basically you get 10Mbps per phone line tops over the 1.5 we max out at now.
"The real problem is that the guys in charge have so very little motivating them to implement new and better things..."
.. like 15-30 miles from the telco ...
"Why bother?
Do we actually think for a moment that US telcos will adopt anything decent? Please...if it's not a patented US currency printing press or a customer cornholing machine...they won't be interested."
And even better...
"For example, on longer phone lines, ADSL2 will provide a data rate increase of 50 kbps--a significant increase. This data rate increase also produces an increase in reach of about 600 feet, which translates to an increase in coverage area of about six percent, or 2.5 square miles."
Wooohooo...a whopping 50kbps, 600 feet...WOW...totally worthless! In about a zillion years they'll have enough range to reach me at 60,000ft from the nearest CO. Hell, telcos can even measure their copper runs accurate to 600ft. I'm serviced at my office at an actual copper length of 19,200ft...while Verizon originally estimated under 15,000ft.
Wow!
It's good for a total of 8,000 feet! Instead of screwing around with short length technologies, why don't they develope something that has far better range
Quidquid latine dictum sit altum viditur
Plus the ability to provide faster service to closer customers , and the ability to bond channels together to get higher bandwidth for business customers ... well heck , who needs a T-1 when you can get superior bandwidth for less ?
I for one am excited that the technology is maturing.
The fact that no one understands you doesn't mean you're an artist.
What will the costs be, as compared to the old standard? One would think that coming up with this new ADSL2 standard would be allow them to increase their range more than just 600 feet, which unfortunately leaves me off the list of getting any broadband in the future.
Is there someone who could shed some light as to why the limitations on the ADSL2 standard have barely been increased?
will happen first: DSL2 will be rolled out or they'll be able to decide on a freaking nomenclature for it?
First of all, the story at broadbandreports.com is nothing but a short blurb about the story at ISP-Planet.
Second, the people who posted comments didn't read it. Not sure what the original author meant by a 50kbps increase, but earlier in the article he mentions a doubling of the frequency used resulting in a doubling of the downstream bandwidth. That's significant to me.
I just signed up for a 12Mbit line here in Tokyo.
(I'm upgrading from 8Mbit - the 12 is actually a cheaper plan.)
Regular DSL, IIRC. Used the 30 year old wiring in my place, no problem.
Even on the 8, I've had Internet downloads stream in at better than 1500K.
A year or two ago, Japan was *way* behind in internet access - I was using ISDN (cheap here) and I was a bit of a rare case. Most people used dialup.
So what's really holding DSL back over there? I'd bet the reasons were more economic than engineering.
Just a thought,
Jim
-- My Weblog.
I can't see that this would be all that useful. While a very cool upgrade for the sake of very cool upgrades, how is it all that great?
My DSL connection is very high speed. I feel no net slowdown when listening to Shoutcast Radio on a 128Kbps station; even though I'm eating up 1/4 of my downlink, only rarely does it actually have an effect.
The slowdowns are at the other end. The servers are overloaded; its their T3s that need to be upgraded. Although 500,000 hits in the period of an hour would swamp anything, I suppose.
So while this idea has merit, a whole bunch of other stuff would have to improve too if this is to be particularly useful.
Warning: Poster of this comment is a nerd. Just like everybody else here.
I mean honestly, I am sure that someone here can explain why DSL is fundamentally going to be limited as far as bandwidth and range goes. Copper is a very lossy media, and we already have better stuff out there like fiber optic, and even fiberless communications versus mutliplexed wavelengths (eg Lucent) or even things such as wireless LAN's (although with a more limited range).
The point is that what we need is something that is a complete departure from the paradigm of cable and DSL modems. That is the only thing that is going to allow us to ALL have broadband, and for the cheap, at very high speeds. I have no idea what it will be, though I think it will have to be some wireless technology. Until then, I think we are going to be stuck in this rut of a small number of broadband users who get to use a flawed and unsatisfactory system (except for those that just surf and check e-mail) due to speed constraints and whatnot.
Any ideas of a new system, or how long one might take to engineer? I'm guessing around 20-35 years.
Imagine a beowulf cluster of cows.
Remember your high-school geometry , area of a circle is pi(r^2)
So the 6% ( ? ) increase in range translates to a more than 12% increase in coverage area. It's not as small as first it appears.
The fact that no one understands you doesn't mean you're an artist.
Well, OK, but for those of us who bought our houses four years ago based on proximity to the CO...
Infill real estate, the plastics of the aughts.
...as a new iteration of the ADSL standard? A 6% gain and negligable service area increase are hardly worth hearlding as a revolution for ADSL. An upgrade, sure, but with such low gains, it may not end up being cost-effective to undergo the upgrade to new hardware, with DSL modems costing up to $200? Most customers probably won't be impressed. I, on the other hand, would give head in an alley for an extra 50kbps. Sign me up.
[este]
The article says that there WILL be an increase in service radius by 6% from the telco loop to your home. Which translates into bigger area of service (~2.5 mi.)
Live for the present, learn from the past, and dream of the future!
Well this is all well and good, but lets keep in mind that dsl is expensive to roll-out, what is motivating the company I work for to go out and purchase this *new* wonderful equipment which is going to require upgrades at least in the DSLAM's / ATM switches, nothing is just "hook it in and it works", ever.
It's wonderful that they claim these super fast speeds, but what's the point right now? My company already has equipment in place to offer a few megabit to the home user, but we don't currently offer speeds faster then 768/768. Why? Because the demand isn't there, period. A few geeks here and there, or maybe a business or two, but most business that need something faster then 768 symetric are going to go with another dedicated telco soltion such as a T-1, or a DS3.
I'm happy that we have these wonderful systems, that promise super fast bandwidth, and I'm not saying I don't believe the speeds, I'm just skeptical that we're going to see them hitting the market anytime soon because phone companies aren't eager to roll them out, keep in mind they're all still trying to re-coup the costs to roll out the network in the first place.
two minutes before action
This is as ridiculous as AMD releasing processors in 66mhz increments in the days of 2ghz+ processors. I can't get DSL because I'm about 5,000ft long of the limit. I can't get wireless without having a HUGE antenna because of the tree line, and no one is offering peer-to-peer wireless yet (if that would even help). I can't get cable because AT&T INSISTS that their services aren't available where I live, despite me receiving monthly bills from them and my neighbor 30 yards away having digital cable. The only thing I CAN get, besides 22k dialup, is 144k IDSL for $140/mo. Screw that. I don't even live in the sticks/boonies.
What the hell is going on? 50kbps and 600ft extra? And it's taken them how long to figure out a way to get that? Where's the innovation? Where's the "space-age", "21st century" technology? We can get a man to the moon and a robot to Mars, but we can't get a decent internet connection to ME!
VDSL holds a bit more promise, I think.
My ADSL was converted to VDSL last month. I live in Korea, and this county doesn't have the issues that consumers in the US are forced to endure. The telco's in the US are still trying to squeeze pennies out of legacy communications infrastructure...I don't see any change coming soon.
For me to take advantage of this two things need to happen.
1. My internet provider is going to have to remove the 1 gig a month limit (if real expects to download movies).
2. Verizon is going to have to provide 1.5 m/bit or faster connection for the price of my current 768/128 k/bit connection..
"I bow to no man" - Riddick
It sounds like you are living quite a bit from telco loops, so have you considered SATTELITE net or maybe [if your area has it] cable? Cable can get quite a decent bandwidth..only drawback is if a whole ton of people log on...it tends to get a **bit** slow. Stattelite is relativley constant and you can eliminate the upstream dialup if you get one od those bi-directional decoders/providers (not available everywhere), though if you live in a stormy/coudy/snow prone area it may not be exactly a good option.
Live for the present, learn from the past, and dream of the future!
What should we expect from cable? I mean ADSL wiring had a lower (6.3 MB/s??) theoretical bandwidth than cable (~10 mb/s). SO in theory shouldn't the speed of cable connection increase on the next revision...
I may be missing something here....
Live for the present, learn from the past, and dream of the future!
I would imagine that telcos will start doing more of what they did for my neighborhood - install a box (looks like a large refridgerator on its side) that essentially functions as a mini Central Office. So even though we're 20,000 feet from the actual CO, we get DSL connections that are under 2,000 feet.
The telcos know they have to do something before they get their clocks cleaned by the cable companies and wireless T-1 providers (notwithstanding the limitations of those technologies - they do kick ass on price, which is all 85% of the market cares about). Expect to see more of these remote-CO things (pardon the technical description) in the future....
Help save the critically endangered Blue Iguana
Over here in the Maldives we pay ~USD45 to every 250MB for a 256kbps DSL line. When newer better technology comes in that price is going to sky-rocket. When are the enablers of technology going to start thinking about moderating that which they breed?
It's here for you!
Faster DSL is useless in the states until the telco's quit guarding and charging for broadband lines like it's their damn cherry. When that happens, ISPs might actually be able to afford to serve the "ulimited" service they claim without pruning off the people that actually use their share of bandwidth.
Example? T1 prices 5 years ago where $400 to $800 a month and T3 was about $8000 a month. Now? T1 is about $400 to $750 a month and T3 is about $6500 a month on up.
Any sufficiently advanced influence is indistinguishable from control.
One of the problems with DSL is the cost. With the decrease of cost, you have an increase in usage and an increase of encouragement to expand coverage.
Hopefully ADSL2 may decrease cost for ADSL.
Fight Spammers!
Exactly where I wanted to cum in. Hey, that's what SHE said!!
They say it should be backward compatible with current hardware.
Yeah - they say that now while there is undoubtebly development cash around - who wants to bet it won't be once it's released?
We have dancing fairies with magic wands that give geeks SDSL for the price of dial-up from AOL. We also have DSL that can reach more than 100 miles from the teleco. As amazing as it sounds, this is all a BLOODY fantasy you dumb ass tards. Stop complaining and live with what you got. If you want decent internet access move to a major city like the reset of us overcharged suckers
"ADSL2 is a new standard that will eventually supersede existing ADSL standards. G.dmt.bis and G.lite.bis are designations for G.992.3 full-rate ADSL and G.992.4 for splitterless ADSL. The beauty of ADSL2 is that it is interoperable with existing ADSL deployments--it will perform both ADSL and ADSL2 modes of operation. This is essential to current ADSL providers--providers need to be able to continue to use the equipment they have invested in."
Backwards compatiable with all the previous modes of ADSL.
"ADSL2+ is an extension of the new ADSL2 standard that should be approved by the ITU early in 2003. ADSL2+ is a hot topic because it is capable of doubling the transmission speed of typical ADSL connections from 1.1 MHz to 2.2 MHz. This doubles downstream data rates to over 20 Mbps, but these data speed rates will only be attainable on loops shorter than 8,000 feet. Here's where things get a bit jumbled--ADSL2 is often called ADSL+, but most experts expect that ADSL2+ will be the term used within technical circles, as this name highlights that it is in fact an extension of ADSL2."
ADSL+ only can reach it's "theoretical" maximumn within a 8,000 loop.
"ADSL2 has been engineered to improve the rate and reach of ADSL by overcoming narrowband interference over long lines. ADSL2 accomplishes this through its improved modulation efficiency, which enhances the signal processing algorithms.
For example, on longer phone lines, ADSL2 will provide a data rate increase of 50 kbps--a significant increase. This data rate increase also produces an increase in reach of about 600 feet, which translates to an increase in coverage area of about six percent, or 2.5 square miles. "
Sounds like the same progression that modems went through.
"In order to diagnose and fix problems, ADSL2 transceivers provide measurements for line noise, loop attenuation, and signal-to-noise ratio (SNR) at both ends of the line. These measurements are collected using a special diagnostic testing mode even when line quality is too poor to actually complete the ADSL connection."
AND
"Additionally, ADSL2 includes real-time performance monitoring capabilities that provide information on line quality and noise conditions at both ends of the line. This information is interpreted by software and then used by the service provider to monitor the quality of the ADSL connection and prevent future service failures. It can also be used to determine if a customer can be offered higher data rate services."
Can anyone say QOS?
"As if simplifying the deployment process weren't enough, ADSL2 also reduces overall power consumption while maintaining "always on" functionality. First-generation ADSL transceivers always operate in full-power mode even when not in use. In contrast, ADSL2 brings in two power management modes. The L2 low-power mode rapidly enters and exits power consumption based on Internet traffic running over the ADSL connection. The L3 low-power mode is a stand-by setting for when the connection is not being used for extended periods of time."
Lower power bills for someone and less interference.
"
The commercial bond
When it comes to commercial DSL services, today's carriers strive to provide different speeds to different customers. For example, carriers want to deliver a standard bandwidth requirement to the majority of home users while providing higher bandwidth offerings for corporations. To do so, they use bonding to aggregate the bandwidth from more than one phone line.
However, Benini said this has been a problem, since the original ADSL standard did not support bonding. ADSL2, on the other hand, does support bonding, enabling the delivery of larger pipes that can compete with dedicated telco services. "Bonded DSL lines are the key to offering fractional T-1 services, or even connections that range between a T-1 and a T-2," Benini said. "ADSL2 offers flexible data rates that carriers can build new offerings around. Through bonding, carriers can increase the data throughput on an ADSL channel to as high as 40 Mbps."
To provide bonding, the ADSL2 specification taps into the inverse multiplexing for ATM (IMA) standard developed for traditional ATM architectures. Through IMA, equipment designs can bind copper pairs in an ADSL link. The result is a far greater flexibility with downstream data rates:
* 20 Mbps on 2 bonded pairs
* 30 Mbps on 3 bonded pairs
* 40 Mbps on 4 bonded pairs"
Now how does this compare to what business are presently using?
" Bonding using ADSL2 is expected to play a role in helping carriers to provide bandwidth-hungry applications such as video and gaming to residential customers. It will also be effective in delivering high-bandwidth services to businesses that prefer asymmetric over symmetric data rates."
Note the mention first of tiered service, one lower bandwith offering for residential customers, the other for commercial, and using bonding to achieve that. Then mentions "bonding" and greater bandwith for the residential customers. Parity?
The story
ADSL2 and 2+ are only going to further the gap between what is possible, and what my ISP offers. It's still a good thing, but I doubt it will benefit the regular Joe, at least not for quite awhile longer.
Or I could be wrong. Whatever. I'm tired.
"But the cars are all flashing me, bright lights are passing me, I feel life passing me by" - Stiff Little Fingers
I dont see how having the actual line from the customer to the ISP 2x faster would help in getting faster connetions to the customers. From what I know, its the bandwidth from the ISP to the rest of the internet which costs money, and doubled access speeds for the customers = doubled bandwidth usage = double costs. Not to mention how much it would cost to upgrade all the old ADSL stuff to this new standard.
At least where I live ADSL is still rather expensive, the fastest line, 2Mbps/512Kbps available is way beyond anything a regular home user could afford, and I dont think thats because of the ADSL tech (They could pump that up to 8Mbps with no hassles) but for the costs of that line for the ISP.
The internet economy will continue to choke until this country / world is rewired at the core to make publishing on the internet once again available to everyone. Even the companies charging for bandwidth won't show profits until bandwidth is cheapened.
The local SBC weenies I have to deal with keep calling those things Remote Terminals, and from what I gather they use a drop of fiber to connect to the actual CO.
What are you doing using the N WORD here?! You must be out of touch! I am deeply offended.
</sarcasm>
they need dsl.00025 to reach my house
Kind of unrelated (read totally unrelated): this shithead needs some flamework.
wow this is so impressive it's faster.....one problem though it does nothing for those of us here in my area becuase we can't even get normal dsl.....last mile bridged my foot /grumbling
All this stuff is down at the physical layer. There's no mention of the higher layers; apparently we're still stuck with PPPoE, a login mechanism, and client software.
The big win with this thing will be the improved diagnostics, along with slightly better noise immunity and the power-save modes.
..but still I can't get ANY form of broadband. And I'm not even living in the sticks - I live in a fairly large English town, which the government had the nerve to dub "IP-City", even though 90% of it lacks any form of connectivity above 56K. I know this is offtopic, but damn it, when I sit here with a connection which I pay more than broadband for, which also ties up the phone line and disconnects every 2 hours, I feel real mad and need to rant about it. Oh, and from my window I can see the BT lab where they develop new and exciting broadband technologies, and then fail to deploy them anywhere near.
This is what you get when you keep on electing a government led by a snivelling weasel who won't do anything unless Bush tells him to first.
Okay, so ADSL2 may double the rate, but whats so gr8 about it anyway? The ISPs get have mostly got a fiber backbone and atleast the small ones pay by data traffic rather than by time, i.e, a fixed price per month. So effectively that translates into no price cut for an average consumer. I mean how many of us are really feeling constrained by the max rate of ADSL1? How many of us use that kind of bandwidth anyway?? So, yes, this technology maybe good for the ISPs but I dont think that the average Joe will notice any change.
What's under yellowstone?
Let's call the existing distance (not specified in the article), "r". So the original and new coverage areas ought to be (in terms of feet):
orig_coverage = pi * r * r
new_coverage = pi * (r + 600) * (r + 600)
The difference between these is claimed to be 2.5 square miles. Since there's 5280 feet in a mile, the difference between these two is supposed to be:
new_coverage - orig_coverage = 2.5 * 5280 * 5280
So, putting these together, and multiplying out the (r+600)*(r+600) part, it ought to be possible to deduce the original radius: ....adding some parens to make it easier to read
(pi * r * r) + (pi * 2 * 600 * r) + (pi * 600 * 600) - (pi * r * r) = 2.5 * 5280 * 5280
So, luckily the r squared terms subtract each other out, so this little bit of math won't requiring using a quadratic equation. Subracting the constant, it turns into:
pi * 2 * 600 * r = 2.5 * 5280 * 5280 - pi * 600 * 600
Now for anyone reading this far who's good at basic algerba, I'm going to appologize for yet a couple more simple steps spelled out....
r * 3769.9 = 69696000 - 1130972.4
r = 68565027.6 / 3769.9
r = 18187.5
So it looks like existing DSL goes 3.44 miles, and this new one goes 3.56 miles, and the increase from 37.276 square mile to 39.776 square miles really is 6% (actually 6.7%).
So it does really work out, and the existing DSL distance of 3.44 miles sounds reasonable.
Of course, it's all a moot point if the FCC allows the cable and baby bells to lock out competition. The only reason almost anyone has DSL within a 3.44 mile radius is because AT&T started rolling out high speed cable. What this new DSL _really_ needs (other than a real increase in distance) is a competing technology/business and a regulatory environment that allows that competition instead of squashing it. How likely is that? Too bad there's no easy formulas there.....
PJRC: Electronic Projects, 8051 Microcontroller Tools
Speaking as one of those in the UK sitting pretty much on the wrong side of the limit of the 5.5km restriction we have on British Telecom's ADSL implementation, the range increase may be more promising.
I'll hit the maths a bit -
Asssuming all the lines radiate directly out of the exchange so you can assume the range limit proscribes a circle with the exchange at the center (you can tell I'm a physicist can't you?)
The range increase talked about in the UK is 5.5km -> 6km of cable length. Now compare the areas of these 2 circles.
5.5 x 5.5 x 3.14 = 95 km squared (approx)
6.0 x 6.0 x 3.14 = 113 km squared (approx)
So this gives an extra 18 km squared coverage. If we assume one household per 100 metres squared (not unreasonable in the UK) then this bring 1800 homes in range of broadband.
Of course in the real world things will vary, but I've seen figures from BT suggesting 6km will bring 97% coverage of the population.
The irony for me is I live 30 miles from London, 4 miles from the end of the runway of one of our major airports, 3 miles from one of the major motorways and yet my broadband options are the same as someone on a remote island, no ADSL, no cable, just my trusty 56k jalopy...
The problem isn't really in the engineering or design, but the roll out.
The most significant bit of any telco's network is 'the last mile' where the copper leaves the exchange and gets to your office or home.
There is one heck of a lot of these local loops, and replacing them with another media is no small job. So the solutions that will succeed and can be rolled out in a reasonable time and at a cost the consumers will pay has to be ones that can make the best use of the established transmission media that goes past your house.
Now this means cable modems and ADSL.
Wireless has its own set of problems if it is to become ubiqoutous - do we have the bandwidth when we are all sharing it - maybe we can have local sub exchanges that feed signal to our houses by fibre?
I don't know the answers, but anything that involves replacing the media to every customers home is going to take a long period of time and money to roll out. Replacing the local loop physical media will not in anyway make broadband cheap, more likely the opposite.
Right now you can get fast reliable connections by buying in a T1 leased line - but most people can't because you have to bear the cost of the telco installing the dedicated line yourself.
We have plenty of technologies right now that can bring mega bit levels to your home - if we were starting from scratch.
I'm not convinced that there is enough frequency spectrum to get mega bit broadband wireless to all. My money would be on a hybrid structure pushing the fibre networks further out to your house as and when networks are updated, and using local nodes and short copper runs like cable modems, or ideally push fibre into your homes in metropolitan areas, moving to wireless links where replacing physical transmission media become cost ineffective.
But 103%^2 > 106%.
Yeah, I know -- everyone hates a pedant.
Yeah, but does this now mean that I can get connectivity for my model train ???
This is going to be a bit long but bear with me, I hope I can explain it a little.
The fundamental limit of high bandwidth technologies is due to the physical nature of copper wire.
Any digital signal is essentially a composition of a series of sine waves. Don't worry if this doesn't make sense - what happens is that the sharp 'edges' of a digital pulse are effectively very high frequency. So although it is conventient to think of a digital signal having a single frequency that is effectively the data rate, its not actually true.
One of the properties of copper wire is that different frequencies travel at different speeds in the wire, and get attenuated (lose power) at different rates.
Now we combine these two thoughts and what happens is that the well defined pulse get smeared as the frequencies that make them up seperate as the pulse goes down the line, and misshaped as attenuation kicks in. At some point this smearing will make it impossible to reconstruct the pulse. Also every single joint in the cable causes reflection of the siganl to some point.
In a transmission system this is not a problem, as the great thing with a digital signal is we know it only has two states - 1 or 0 - so we can regenerate and clean up the signal and transmit it again. This is what repeaters in undersea cables do (even fibre has to have these, but at much greater lengths than copper). But to your house there is no point in the cable to put a repeater - if the signal can be read when it gets to where you are then it works, if not then it doesn't.
Now in reality digital signals are not transmitted as a single stream of on/off pulses, but encoding systems are used that turn the signals into ranges of tones - which is why when you listen to you modem you here a range of tones, rather than a single one.
All of these techniques aim to minimise the effect of the smearing due to the different speeds the different frequencies travel, and to make the signal more resiliant to noise issues. But at some point either the pulses will become so corrupted they cannot be recognised, or the signal to noise ratio will get so bad that they can't be distinguished from noise.
Generally the problems get worse as the frequency goes up, and in data terms this is roughly the same as baud rate. This is why faster DSL rates are only available nearer the exchnage.
The reasons why ADSL2 isnt a great improvement is we are hitting fundamental limitations of copper wire transmission systems as used for analogue telephones (and it is analogue in the local loop no matter what the exchnage is) and tweaking the encoding techniques is not bringing great increases.
Remember with normal modems we hit the limit at 36Kbaud due to the fact that normal voice is limited to 0-4Khz - a bit of clever engineering managed to boost this to 56Kbaud on the downlink because you avoid one of the anti aliasing filters in the exchange.
So modems are limited to 4Khz and Shannons Law tells us the maximum data rate we can do at 4Khz, and 56Kbaud modems are damn near the limit.
ADSL is carried as a piggy back signal on your analogue line - below 4khz is the normal voice signal, above 25Khz is the ADSL signals. There is no 'hard' upper limit to ADSL due to filters like there is for voice, but there is a 'soft' limit where the problems discussed above mean its not possible to get reliable transmission.
Current ADSL is pretty close to those 'soft' limits - ADSL2 tweaks it a bit to get more in and increase the range.
The bad news is its not going to get much better on copper wire - the modem limit was due to filtering, but ADSL is down to basic physics.
Explanation of the local loop technologies - mostly found via ADSLGuide (These guys do a great job of keeping on top of UK ADSL issues)
The Last Mile - personal site, but a good heads up. Significantly shows the bandwidth limits as related to the type of wire the signal is transmitted down.
The Trouble With DSL great well written article that summarises some of the technical and practical issues with DSL.
ADSL Techincal Summary
DSL Source Book - PDF (registration required) - very good for technical geeks.
Obviosly the ONLY possible use for a fast connection is to download copyrighted movies so the government should require each user to get a hand-written permission slip from a movie/record exec. Think I joke? Just wait....
We should learn from Microsoft. It shouldn't me ADSL2... but ADSL2002. It's not just twice better, but 2002 times. :)
-
ping -f 255.255.255.255 # if only
/.
A minor improvement, great so what?
My local municipal owned and operated cable company had Gigabit Ethernet available to business and local government.
They used to have a one way cable platform for residential at speeds the same and under, priced above Bell (and Earthlink) DSL.
Don't think that having more than one provider is going to break any barriers in competition.
Most area's that could have multiple high speed providers don't. The Bells and the Cable Co's are dividing the marginal area's up, and choosing which high return (read big city) areas are worth fighting for.
Gigabit, not 2.8 megabit, now there's something everyone should have.
I for one am happy to hear any news about expanding DSL service area and raising bandwidth to the customer.
That said, it is now time for the Bob-o-Matic gripe and brag:
What is the problem, PacBell?!?
Why does it take over a month to activate a DSL line (everything was self-installed within 10 minutes of receiving the package), and cost $50 per month for 384kbps down/128kbps up service?
I am stationed in the Republic of Korea now, and my DSL service was delivered/installed/activated/tested within 3 days of my phone line activation!, less than one week after I first contacted Korea Telecom.
Here is the real kicker: My combined phone/ISP service bill here is LESS THAN MY SLOW-ASS PacBell ISP service alone!
Now, the brag: Kornet MegaPass Premium service is 8mbps down, and about 1mbps up, for (at most) 43,000 Won per month, or less than US$40. BTW I downloaded RH 8.0 from a Japanese mirror at an average of 26 minutes per iso. Also, I am known to fill the 60GB DeathStar in less than 4 days after it dies... Thanks, Kazaa-lite!
The telcos know they have to do something before they get their clocks cleaned by the cable companies and wireless T-1 provider
I'm not sure how COs work in the states, but here in Canada a very good percentage of the population is within ADSL distance of a CO. Having said that, indeed they have been moving to remote COs, although ADSL is only a very small reason why: They simply make more sense. Why run an entire neighbourhoods copper pairs to the CO (and copper isn't cheap) when you can run them a much shorter distance to a little box and run a fibre back from that.
Seriously DSL is a loser technology...I have yet to see the telco that can provide the same speed on DSL that I can get from my cable company on my cable modem. In New England where the DSL provider is almost universally verizon for the home subscriber (and even if its not it is since
other providers are basically forced to use verizons lines and services), your also stuck with PPOE...which is a horible technology...I am on the VPN team at my company, and we have to tell users of verizon DSL to purchase a linksys router to even use the VPN software since the PPOE client and the Cisco VPN software conflict with each other.
The only impending technology that will really get me excited is when someone (cable-co, or telco?) tells me I can get a fiber drop and a couple IPs to the home. Plug the fiber drop into my router and just be there all happy on the internet.
Power Corrupts,Absolute Power Corrupts Absolutely, leaving one person(group)in charge is absolutely corrupt.
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Now instead of being 58000 ft too far from the CO, I'm only 57400 ft too far from the CO. At leaps and bounds like this, by the time they get to ADSL97 I'll finally be able to get service. :)
The advance in technology isn't coupled with an advance in the method of delivery. It will still be administered by the progeny of Bell and, if they can find any way to screw it up, they will.
The trouble with practical jokes is that very often they get elected. -- Will Rogers
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We have no DSL, but we know that our Dear Leader Kim Jung Il invented the internet. Not that crazy round eye imposter Al Gore!
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Instead think of them in a larger scope.
Many Telcos are starting to roll out evironmentally hardened DSLAMs that they can pole or slab mount to serve areas that have demand but are too far from an existing DSLAM.
If a Telco can now reach a larger subscriber base without rolling out as many remote DSLAMs, that results in an increase in available infrastructure dollars, which could translate into fast or a greater number of remote DSLAM rollouts. I can also increase DSLAM rollouts by increasing revenue per DSLAM, since a given DSLAM can now service more customers, which might in turn make more DSLAM rollouts more affordable for Telcos.
"would imagine that telcos will start doing more of what they did for my neighborhood - install a box (looks like a large refridgerator on its side) that essentially functions as a mini Central Office. So even though we're 20,000 feet from the actual CO, we get DSL connections that are under 2,000 feet."
Your exactly right. I live out in what people would call the boonies. Cows, chickens and goats are my neighbors and I am waked up by howling dogs and roosters. However, I get very fast and reliable dsl access. I've had 1.5mb/s down and 256kbs up for a year now at $45 a month courtesy of my baby bell. It has only gone down 4x in the course of the year that I have had it, which is better than I can say about the dialup i used to have. I wish the bandwidth were higher, but I can't complain, because I don't get capped like so many cable users do. I live in an unencorporated town that is about 15 miles outside of Atlanta. They have one of those boxes not far from me, and the tech who had to repair my dsl told me that their little foray is doing well, we have 40 users on our Dslam. By extending the reach of DSL, they are able to capture the upper middle class market who live in the suburbs. Hopefully, your local telco will experiment in your area in a similar manner.
13 year old white supremacists are shitty web designers.
Someone please help me out and explain where this "soviet russia" thing came from.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Well, Verizon just had some contractors pour a slab at the end of my road, with some conduits from there to a nearby pole which already had a cutdown box on it.
Now are they going put in a remote terminal and give us all DSL before Comcast rolls out cable modems ? (this is a town that ATT wired 27 months ago with fiber and then walked away from when the
Comcast deal got started)
Or are they just doing this to service a new development that's being built a couple miles down the road.
I'm not holding my breath...
Don't get excited. The new standard will not impact you because you won't get higher rates to your home and you won't suddenly get service where there was none before. At least no time soon.
ADSL2 is what happens when you take a bunch of high-brows and send them off to places like Melbourne, Geneva, Nuremberg, Belgium, and Fiji. This was all during the high-tech boom and now everyone is post-boom and going "what were we thinking?".
The only real strength to the new standard is in the area of line diagnostics and the ability to provide more feedback at the CO into why errors happen.
Backwards compatible? Not! *Some* modems and switches can be software upgraded to support the new standard, but let me tell you, its one hell of a re-write. The compatibility talked about in the article is simply referring to the fact that we don't have to rip up all our phone lines to make this work. Jeez, really?
Higher rates? (ADSL+) Sure, but guess what? That feature has nothing to do with ADSL2 and could have been provided under the umbrella of the existing standards (by extending them). And -- there's no way hardware in existing modems and dslams will support the higher rates. You'll have to wait for new and more expensive hardware for that.
And higher rates for who exactly?
Most of you people who are stuck with 1M DSL don't realize that the current standard supports over 10Mbps downstream and over 1M upstream. Most of the modems and dslams out there today will support up to 8Mbps down but the phone companies usually don't provision it. ADSL2 and ADSL+ will not change this.
The phone companies *will* pick up this solution to get that extra 600ft to increase their user base. This means users getting 1M service, by the way.
Majik
What I'm saying is that someone should think about a technology governance structure as did FSF inspire open source methodology.
What I'm waiting for is not a bigger pipe, but cheaper bandwidth. The last thing I need is technology that will help me spend the same amout of money twice as fast.
I work for a telco. We run ADSL and ADSL+. Our customers negotiate and run full speed (all the pair can handle). To control the bandwidth they use, we shape their traffic as they enter and leave the network.
As for the speeds of the two technologies . . . ADSL (G.DMT) will link at 6Kft or less and give anywhere from 60-80% of link speed. I am currently running on a 900kbps/7600kbps link and get 800kbps/6000kpbs of real throughput. ADSL+ will link at 900kbps/9000kbps or greater and will get 800kbps/8000kbps or greater. But, all these conditions are subject to proper pair qualification and distance limitations.
Pretty much anything below 6kft will be wonderful. From 6-12kft there will be a 10-20% decrease in speed. From 12-15kft there will be a 20-30% decrease in speed. From 15kft on out we would switch the customer to G.Lite (1000kbps/4000kbps) which will run out to 24kft at some proportion of the rated speed. At 24kft a costomer will likely get 256kbps/512kbps . . . which is nothing to sneeze at. We have a neighboring telco which has a G.Lite customer at 27kft of 19 ga. copper running better than 256kbps/512kbps (although I have not heard any results of throughput tests on that link).
Remember, not all telcos are created equal.
Excerpt from a conversation between a customer support person and a
customer working for a well-known military-affiliated research lab:
Support: "You're not our only customer, you know."
Customer: "But we're one of the few with tactical nuclear weapons."
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