Subject: General Tech | August 5, 2013 - 07:10 AM | Tim Verry
Tagged: rf, itu, gigabit broadband, fttdp, fiber, broadband, bell labs, alcatel lucent
Alcatel Lucent has been working on a new broadband technology called G.Fast that is currently undergoing ITU (International Telecommunications Union) scrutiny and may be ready to implement as soon as 2015. G.Fast is a technology that builds upon VDLS2 and is the next step between the currently-popular FTTN (Fiber To The Node) and true fiber FTTH (Fiber To The Home) internet services. Alcatel Lucent’s G.Fast technology is rated for speeds up to symmetrical 1 Gbps over copper lines up to 200 meters and 500 Mbps at up to 300 meters.
G.Fast is currently being tested by Telecom Austria and is being evaluated as a standard by the ITU. G.Fast requires fiber to be pulled closer to consumers, but avoids the massive expense of doing true fiber runs to each individual home. Unlike traditional DSL which is served from a central office up to miles away, or newer VDSL technology like AT&T's U-Verse service that is served from a DSLAM that is located about a mile from customers, G.Fast serves customers from a fiber distribution point that is a maximum of 300 meters away from customers. In the latter two cases, the internet connection is fiber up to the DSLAM or distribution point after which it uses the existing copper phone lines to reach customers' homes. The G.Fast distribution point is about the size of a large shoebox and can be mounted on telephone poles or underground.
G.Fast implements pair bonding, vectoring, and phantom mode techniques (more information, PDF) in addition to a physically closer fiber connection (internet speeds drop off dramatically as copper cable length increases due to cross talk on the cables, interferrence from other RF sources, and other factors). Specifically, G.Fast is able to use multiple physcal copper pairs (pair bonding) along with multiple virtual pairs per each physical pair (phantom mode), and an active noise monitoring and cancelling system to reduce cross talk and interferrence (vectoring). Additionally, G.Fast uses a surprising 100Mhz of spectrum over the copper pair(s) and fancy modulation techniques to wring all the speed possible out of existing telephone lines. For comparison, traditional old-school DSL that you would get from your local telephone provider uses less than a MHz of spectrum, and the latest VDSL2 technologies use around 1MHz of RF spectrum! There is an interesting problem with G.Fast beyond punching all this through the cables, and that is possible issues with FM broadcasters (radio stations) that use RF spectrum between 87.5MHz and 108Mhz. The Register notes that ISPs that implement G.Fast will have to work around the specific FM frequencies actually used in the local area to avoid interferrence. That suggests that operators may not be able to use the full 100MHz of spectrum in the standard, but it would still be a huge step up from VDSL. The site further explains that even if the copper lines are buried underground, it could still cause issues with FM broadcasts as the 200-300 meter line makes for a massive antenna.
Another point in favor fo G.Fast is that it is designed to be a customer installed technology in the sense that customers will be able to plug in their modems to the standard phone jack and recieve service. (Ideally, this would mean no need for technicans to do so-called "home runs" to get the best speeds, but if it is needed with U-Verse it may still be needed for G.Fast, especially in older apartment buildings.)
The ITU is currently looking at G.Fast and working towards a standard along with developer Alcatel Lucent and various telecoms interested in implementing the technology. According to Frank van der Putten of the ITU, G.Fast could be approved as soon as early 2014 with hardware supporting it available in 2015.
G.Fast is by no means the end-all-be-all of internet connections for home users, but it is a massive performance leap ahead of current DSL technologies and thanks to competition from Verizon FIOS, Google Fiber, local municipalities building out their own fiber neworks, and cable companies (in the US at least, where internet over coax is common), G.Fast may be economical enough that telecos are willing to upgrade their networks to head off these competitors all while moving their true fiber networks all that much closer to people's homes and to the (hopefully/ideal) eventual implementation, and final upgrade to, Fiber to the Home connections.
Subject: General Tech | March 27, 2013 - 11:01 PM | Tim Verry
Tagged: Internet, hc-pbgf, fiber, data transmission
Transmitting data over optical fiber is one of the fastest methods available, and researchers at the University of Southampton have managed to dial up the speed even further.
Being optical in nature, light is used to transmit data over fiber. The speed of light through a vacuum is 299,792,458 meters per second, but traditional fiber is not nearly that fast due to light traveling approximately 31% slower (206,856,796.02 m/s) through silica glass than a vacuum.
The new fiber employs a hollow design that allows light to travel through air rather than glass while still allowing the cable to bend and twist around corners. The new fiber has been dubbed Hollow Core Photonic Bandgap Fiber, or HC-PBGF, and allows light to travel up to about 298,893,080.63 m/s (~99.7% the speed of light). Currently, the HC-PBGF fiber is still in the experimental phase, but it could have big implications for data centers and HPC server clusters that depend on high bandwidth, low latency connections between individual nodes.
Just how fast is the new HC-PBGF? According to ExtremeTech, a researcher told the site that the new fiber has a total cable throughput of 73.7 Tbps. It transmits 3 modes of 96 channels of 256 Gbps each using a combination of wave division multiplexing and mode division multiplexing. The fiber is 160nm and is noticeably faster than traditional fiber. Additionally, the HC-PBGF has a data loss of 3.5 dB/km which makes it a useful candidate for short runs between nodes or rows of racks, but not yet suitable for longer runs. HC-PBGF will not be blanketing your neighborhood anytime soon, but the research may lead to new optical networking technologies used in the next supercomputer or cloud service, for example.
The full paper can be found here, along with more details over at Ars Technica. Unfortunately, the full paper is behind a paywall but it may be worth seeing your school or work can give you access should you be interested in drilling into the details of the experimental hollow fiber,.
Subject: General Tech | June 3, 2012 - 04:23 AM | Tim Verry
Tagged: verizon, pricing, Internet, fios, fiber, 300mbps
According to sources that talked with The Verge, Verizon is planning on offering faster internet services for its FIOS customers, but the new tiers are going to cost a pretty penny.
Verizon will be upgrading many of its FIOS internet speeds, and the changes are set to go into effect on June 17th. The base 15/5Mbps (download/upload) plan will cost $10 more than the current price of $54.99 at $64.99 a month. The current 25/25Mbps will be upgraded to 50/25 and will not see a price increase–it will continue to cost $74.99. The current 50/20Mbps plan will see a significant speed bump to 150/65Mbps, and it will cost $94.99 a month (no price increase). A new 75/35 speed plan will become available and it will cost $84.99 a month. Finally, the service that readers will be drooling over–the 300Mbps plan–will feature speeds of 300Mbps downloads and 65Mbps uploads. It will cost a hefty $204.99 a month, a price that The Verge notes is a mere $5 more than the 150/35 speed tier that it replaces.
Comcast telco fashion, Verizon has managed to tack on up to three fees including a $5 per month fee for those without a contract, a $5 fee for those that do not subscribe to FIOS phone service, and a $100 fee to install equipment for those that want the upper two speed tiers. Fortunately (sort of...), users can avoid the $100 fee if they are new customers or already subscribe to the company’s 150Mbps tier. Also on the less-than-stellar news front, Verizon will not be upgrading plans for those on VDSL plans (in buildings where Verizon delivers fiber to the premises and uses copper from there to homes–think older apartment buildings). Even worse, VDSL customers will still be subject to the increased pricing although they cannot take advantage of the upgraded speeds.
|Single Family Home||VDSL 1||VDSL 2||2 Year Contract||Month-to-Month Rate|
|3/1 Mbps||3/1 Mbps||3/1 Mbps||$54.99||$59.99|
|15/5 Mbps||10/2 Mbps||15/5 Mbps||$64.99||$69.99|
|50/25 Mbps||20/5 Mbps||20/10 Mbps||$74.99||$79.99|
|75/35 Mbps||30/5 Mbps||50/10 Mbps||$84.99||$89.99|
(Source: The Verge. The 150/65 plan doesn't seem like a bad deal actually, if only I had FIOS in my area!)
So this fiber internet upgrade announcement seems great at first does have a dark side. Some customers will be getting a great deal while others will be getting the short end of the stick. Here’s hoping that you are one of the lucky customers on the middle tiers who have FTTH that get a free speed upgrade! More information on the specifics of this upgrade should be coming later this month.
Subject: Networking | May 24, 2011 - 06:52 PM | Tim Verry
Tagged: networking, Internet, fiber
Using a single laser, scientists were able to encode data and transmit it over 50 km of single-node fiber using “325 optical frequencies within a narrow spectral band of laser wavelengths.” The single laser was capable of handling 26 terabits of information per second in an energy efficient manner, which is equivalent to the amount of data used by 400 million phone calls.
The technique used to encode and decode the optical data is called orthogonal frequency-division multiplexing (OFDM). It is a modulation technology that can be applied to both optical and electrical based transmission methods. The data is broken down into numerous parallel streams of data (using mathematics) that greatly increases the transmission speed and amount of bandwidth available. While electrical/copper based systems are not able to transmit 26 terabits of information using OFDM, optical systems are able encode the amount of data in their experiments without speed restrictions and while using “negligible energy.” Dr. Leuthold stated “we had to come up with a technique that can process data about one million times faster than what is common in the mobile communications world.” Further, his stated that his experiment shows that optical technology still has room for transmission speed improvement, and increases in bit-rate do not necessarily result in higher energy usage.
The important aspect of Dr. Leuthold’s research lies in the energy efficiency inherent in reducing the amount of lasers and fiber nodes required to transmit 26 terabits per second of data. Using simple optical technologies, they are able to greatly increase the amount of bandwidth in a single fiber line. Japanese researchers have been able to achieve 109 terabits per second download speeds; however, they had to use multiple lasers to achieve the speeds. Dr. Leuthold iterated that “it’s the fact that it’s one laser,” as being the important results of his research.
Image courtesy Kainet via Flickr Creative Commons
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