In this issue of Telefocal's enewsletter, we are pleased to attach an article on "Synchronisation over Ethernet and IP in Next-Generation Networks" by our Senior Technical Member, Professor Stefano - for your reading pleasure as well as to provide an overview of network synchronisation issues in a converged IP network.
We are also launching the first of a series of Android trainings - Android Fundamentals.
And as usual, an update of our upcoming courses on my right for your active participation.
Feel free to contact me should you be interested to contribute any White Paper or interesting article for our Telefocal community, participate in any of our public training programmes, or if you have any special request for customised trainings for your team.
Synchronization over Ethernet and IP in Next-Generation Networks
- Contributed by Senior Technical Member, Professor Stefano Co-edited by Director Engineering Services, Nazir Uddin Telefocal Asia Pte Ltd
Network synchronization plays an important role in digital telecommunications. It affects the quality of most services provided by the network operator. Presently, synchronization is primarily distributed across circuit-switched telecommunications networks, using traditional Time-Division Multiplex (TDM) links, such as E1 (2.048 Mbit/s) or DS1 (1.544 Mbit/s).
Several fixed line and mobile Operators are migrating to an IP packet-switched network infrastructure, in the framework of Next-Generation Network (NGN). In this architecture, Ethernet transport is common. This trend is driven by low operating costs, bandwidth consolidation of different services and by the convergence between fixed and mobile services. However, migrating trunk lines to IP transport poses challenges, in particular for circuit emulation and synchronization of network elements.
The evolution of communications networks towards packet-switched networks has increased interest in the distribution of synchronization using packet technologies. In particular, synchronization distribution over Ethernet has become a focus of activity in international standard bodies. The ITU-T is developing a set of four new Recommendations on these topics, namely:
ITU-T Rec. G.8261 “Timing and synchronization aspects in packet networks”, consented in 2008, proposed update in 2010;
ITU-T Rec. G.8263 “Timing characteristics of packet based equipment clocks (PEC) and packet based service clocks (PSC)”, updated in 2009;
ITU-T Rec. G.8264 “Timing distribution through packet networks”, consented in 2008, proposed update in 2010;
Another international standard relevant to this issue is the IEEE 1588 on the Precision Time Protocol (PTP) (http://ieee1588.nist.gov/). This protocol can be used to time align hosts with sub-microsecond accuracy exchanging messages on Ethernet networks.
In this scenario, the traditional model in which synchronization distribution
is engineered carefully may make people have a greater expectation
of an ad-hoc synchronization quality, i.e. to expect traditional quality
of synchronization also when the underlying transport facilities are
not the legacy TDM circuit-switched infrastructure. Unfortunately,
this currently seems impossible to achieve and even approaching it
as it requires strong planning capabilities and good knowledge of
all involved issues.
Such issues reach the wider audience of telecommunications engineers.
An example is the distribution of synchronization to next-generation
wireless base-stations, which may only have packet connectivity but
still require high accuracy of synchronization.
In this field, some key and upcoming topics of research and development in both academia and industry are:
the key emerging standards in the area of synchronization over packet networks, including recent work at the ITU-T, IEEE and NIST;
identifying timing scenarios in various network applications;
implementation of devices and equipment cards achieving high-quality synchronization using new technologies for packet-based synchronization transfer;
optimal deployment and roll-out of these solutions by network Operators;
measurement techniques for characterizing and qualifying packet-based synchronization;
circuit-emulation services over pseudo wire;
delivery of synchronization to wireless base stations in 3G/4G networks using Ethernet.
It is maybe needless to say that quality of service degradations due to poor network synchronization look often sudden, unexpected and of mysterious origin for almost everybody but the (good) synchronization engineer.
The course "Synchronization of Telecommunications Networks" offered by Telefocal provides all the necessary basic knowledge that is needed by telecommunications engineers to approach these complex topics and to manage effectively all issues related to network synchronization planning and operation.
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Telefocal Asia is a Singapore-based telecom training provider offering its full range of telecom training services to telecom operators in the world. Whether you are a fixed line operator or cellular operator, greenfield or brownfield operator, GSM or CDMA operator, you would be able to find all the relevant expertise needed for access, core and transmission networks at Telefocal. Our practical approach towards training your key asset, your people, and our ability to provide simple solutions to complex issues provide legitimacy to our presence in many leading operators in the world today. We serve an increasing clientele bearing outstanding testimonials to our commitment, professionalism and expertise, for instance: Vodafone, Alcatel-Lucent, MTN, Orascom Telecoms Holdings, Zain, Ericsson etc that are scattered across fifty over countries. T: +65 6848 7860 F: +65 6846 7920 www.telefocal.com
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