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ITU-T e-FLASH
Telecommunication Standardization Sector |
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New Broadband Standard from ITU Gives 10x ADSL Speeds
ITU-T has completed the specifications necessary for telecoms operators around the world to offer a ‘super’ triple play of video, Internet and voice services.
The ITU-T Recommendation for very-high-bit-rate digital subscriber line 2 (VDSL2) will allow operators worldwide to compete with cable and satellite operators by offering services such as high definition TV (HDTV), video-on-demand, videoconferencing, high speed Internet access and advanced voice services including
VoIP, over a standard copper telephone cable.
VDSL2 will offer consumers up to 100 Mbps up and downstream, a massive ten-fold increase over the more common ADSL. Essentially it allows so-called ‘fibre-extension’ bringing fibre like bandwidth to premises not directly connected to the fibre-optic segment of a telecoms company’s network.
As well as addressing increasing consumer demands, VDSL2 offers telecom carriers a solution that promises to be interoperable with the ADSL kit that many operators already have in place. This interoperability will make the migration of customers to VDSL2 much simpler. Another important feature of VDSL2 is that it will work in both legacy ATM networks and next generation IP based networks.
VDSL2 is seen by many operators as an ideal accompaniment to a fibre to the premises
(FTTP) rollout, where for instance fibre is supplied direct to an apartment block and from there copper cable is used to supply residents with high-speed VDSL2.
Yoichi Maeda, chairman of the Study Group responsible for the work said: “We have leveraged the strengths of ADSL, ADSL2+, and VDSL to achieve the very high performance levels that you will see with VDSL2. It looks set to become an extremely important feature of the telecommunications landscape and is a landmark achievement for our members, many of whom were relying on this Recommendation in order to take their businesses to the next level.”
The publication of standardized specifications in an ITU-T Recommendation
(G.993.2) means that operators can avoid being locked into a single vendor. As well as the economic advantages that this may bring it also means that operators can select the best solutions according to their needs.
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Standard Brings Core Technology to Metro Networks
A new standard from ITU-T's
Study Group 15 gives network operators the ability to deploy multi-vendor dense wave division multiplexing
(DWDM) systems in a metro environment. Defining specifications for interoperability in this field is seen as a ground-breaking achievement, where previously there has been domination by proprietary systems.
WDM technology is used by the owners of optical fibres to maximise their capacity. The technology achieves this by simultaneously operating an optical fibre pair at more than one wavelength. Since operators wish to maximize their cable plant investments and deploy increasingly bandwidth hungry services in a multi-vendor environment, standards development in this field is seen as crucial.
Until now DWDM systems, which have the capability of carrying a high number of channels (up to 80) on a single optical fibre pair, have been deployed in core fibre networks that cover great distances. A different
WDM, technology CWDM (the C stands for coarse) was the first standardised solution for metropolitan areas, but CWDM systems only have the capability of carrying a limited number of channels (up to 12 now, but in the future 16).
This standard (ITU-T Recommendation G.698.1) has been driven by operators and allows them to benefit from the greater capacity of DWDM systems in metropolitan environments while being able to deploy system elements from multiple vendors. The current version of this Recommendation covers distances in the range of 30 - 80 km.
These new specifications have been made possible by the use of a fundamentally different methodology to that used previously according to the experts who developed it. The so-called 'black-link'-approach is seen as a new direction in the standardization of WDM systems, providing a powerful tool to enable agreement on multi-vendor interoperability in a previously proprietary environment.
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ITU-T Recommendation Addresses Lightwave Phenomenon
A new ITU-T Recommendation specifies the characteristics for devices that address a phenomenon known as polarization mode dispersion (PMD) in optical fibres. PMD is caused by a difference of the propagation speed in different polarisations of the light travelling through a fibre. PMD is induced by distortion of the light in optical fibres that occur as a result of the manufacturing process, the way it is laid in the ground, around corners etc.
PMD becomes an increasingly serious problem as the bit rate and the length of optical transmission systems increase. As a result, PMD compensation (PMDC) is an important technology for very high rate long distance systems. For instance at 10Gbit/s PMD is manageable for currently existing long-haul dense wavelength division multiplexing (DWDM) systems but at 40Gbit/s compensation may become necessary.
While there has been knowledge of the phenomenon for some time the PMD-induced penalties such as distance and bit rate limitations have often been considered too difficult or expensive to deal with, and so the telecommunication industry has had to learn to live with the problem. There have been limited efforts to develop solutions which have not evolved into successful commercial products.
In order to address the problem in a more efficient manner and stimulate a market for PMD compensating devices, operators have driven this ITU-T work. By agreeing on a set of characteristics for these devices, operators can look forward to the availability of products that will be more mature and will cost less than developing in-house solutions. It is expected that operators may also see reduced expenditure because it is thought that the use this technology will reduce the need for electro-optical regenerators (devices that break a signal down in order to restore it to its original quality).
Future work of the group that has produced this Recommendation will look at similar devices called adaptive dispersion compensators for another phenomenon called chromatic dispersion that also limits data rates and transmission distances in optical
fibres.
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Design Guidelines for Submarine Cable Systems Issued
ITU-T's
Study Group 15
has agreed on design guidelines for optical fibre submarine cable systems.
Submarine cable systems form a very important part of the world's ICT network infrastructure with cables linking all the world's continents except Antarctica. And as demand for increased transmission capacity increases, owners of these networks are keen to optimize their investments, because laying new submarine cables is an expensive and difficult business.
The guidelines appear in a supplement to ITU-T Recommendations on the topic of submarine cable systems (Supplement 41, to the
G series of ITU-T
Recommendations), and allow for the incorporation of traditional technology (e.g. WDM systems, erbium doped fibre amplifiers) as well as new technology including new generation forward error correction
(FEC) and Raman amplifiers.
According to the expert authors, the document has been produced with a key objective to detail the main technical issues to be taken into account in order to achieve a link's longest distance, with maximum reliability.
The supplement describes considerations for repeatered, repeaterless and optically amplified systems supporting synchronous digital hierarchy
(SDH) and optical transport network (OTN) signals. Repeaterless submarine cable systems are used for terrestrial network extensions in cases where submarine distances up to about 350 km are to be covered. Repeatered submarine systems are used for long haul, large capacity transmission by using submerged optical amplifiers in order to cross distances up to transoceanic lengths.
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Call
for Papers on Next
Generation Multimedia Applications
ITU-T's Study Group 16 has made a public call for proposals on requirements for the multimedia applications that will run over next generation networks
(NGN). The advent of the NGN creates an opportunity for a new - third - generation of multimedia telecommunication systems offering more integrated features, greater extensibility, and more flexible growth paths for the future.
Multimedia systems are expected to form the bulk of NGN services and so early attempts at defining them are crucial. SG16 will combine the results of the call with its experience gained in defining standards for the so-called first and second generation multimedia terminals and systems.
Once it has established what sort of services people think will emerge, SG16 can start the work on the standards to support them. The group's management team said that it is keen to get contributors to think 'out-of-the-box' beyond the usual and the obvious.
The Call for Proposals on Requirements for the third generation of ITU-T Multimedia Systems and Terminals can be found
here
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New Ethernet Services Made Possible
A meeting of
Study Group
15, the ITU-T group responsible for studies into optical and other transport network technologies, saw consent on a new Recommendation that defines the way for equipment providers to produce systems for Ethernet virtual private line
(EVPL) services.
EVPLs offer a way for operators to provide point-to-point connections for carrying data over shared-bandwidth facilities.
The announcement is in line with the current industry trend to offer Ethernet services, and further signals Ethernet's growth in popularity as an enterprise telecom service.
Long-recognized as a ubiquitous LAN technology, Ethernet is now seeing increased attention as a carrier-grade service. In part this is due to the convenience of being able to simply provide end-to-end service, but also carriers can realize savings both in terms of capital and operational expenditure.
In terms of capital expenditure, Ethernet is easy and cost-effective to provision in the network. In terms of operational expenditure, carriers can deploy a single physical connection to the end user, but adapt its data-carrying capacity as end-user requirements dictate over time. This flexibility means a significant saving for the operator and the customer.
This work follows earlier work in the area of Ethernet standards approved last year. See also
press release 8 June, 2004.
The new Recommendation - G.8011.2 - defines the service attributes and parameters for carrying Ethernet characteristic information over shared-bandwidth, point-to-point connections, provided by
SDH, ATM, MPLS, PDH, OTH, or ETY server layer networks.
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RFID Paper Available
In the framework of its
Technology Watch activities, ITU-T has recently published a
technical paper on radio frequency identification
(RFID) and opportunities for its use in mobile telecommunication services.
RFID enables data to be transmitted by a tiny portable device, called a tag, which is read by an RFID reader and processed according to the needs of a particular application. It is only recently that the technology has begun to take off in the mass market. Analysts predict that RFID will revolutionize areas of industry, such as supply chain management and the retail business, for example by reducing costs with better stock management. The technical paper presents several ideas for applications of RFID technology in mobile telecommunication services as well as possible areas for standardization efforts. Apart from purely technical concepts, the challenging aspects of security and privacy are discussed. A
PowerPoint presentation of the paper is also available.
ITU-T recently set up a correspondence group on RFID in the framework of its Technology Watch and a dedicated e-mail reflector on the matter for initiating studies on the technology. Additionally, ITU-T is to hold a workshop on RFID standardization issues in the first quarter of 2006.
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Focus Group Delivers
The Open Communications Architecture Forum
(OCAF), a Focus Group operating under the auspices of the ITU-T,
has produced its first official publication. OCAF was created in May 2004 to accelerate the adoption of an ecosystem of open standards components in next generation networks
(NGN). The mission of OCAF is to help service providers, equipment and software vendors address the complexity of moving to these new packet-based systems. Selected outputs of OCAF will be submitted for approval as ITU-T Recommendations.
The Carrier Grade Open Environment (CGOE) Reference Document – outlines a framework for the open interfaces and standards required to deploy solutions based on standardized commercial off-the-shelf (COTS) components in
NGNs. Available from the OCAF
webpage, the CGOE Reference Document is intended for an audience that aims to integrate solutions containing components from multiple, different, COTS software and hardware vendors.
Typically this will include service providers, solution providers and technology providers.
The model is consistent with the concept that technology providers deliver components to solution providers who then subsequently provide solutions to service providers. OCAF members are already using the model to deploy NGN services and promote best-of-breed component reuse and interoperability in a multi vendor environment.
OCAF has also published a white paper, outlining its work. The white paper, also available from OCAF's webpage details the group's raison d'être as well as giving a detailed mission statement.
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INFORMATION LINKS
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