Optical/IP Networks

Synchronization Still a Mobile Backhaul Challenge

Network operators worldwide have commercial deployment of Ethernet backhaul underway on a large scale now, but most of them continue to leverage time division multiplex (TDM) timing or synchronization because it is the approach they understand best. As operators begin the transition to packet backhaul that will ultimately see TDM timing eliminated altogether, three primary methods have emerged as contenders for the de facto synchronization standard that will eventually allow network operators to retire their TDM networks: The Institute of Electrical and Electronics Engineers’ (IEEE) Precise Time Protocol 1588v2 and Synchronous Ethernet (SyncE) standards and the U.S.-based Global Positioning System. While each of these standards has its own strengths and weaknesses, 1588v2 is the only one that possesses three key characteristics. It can be deployed easily at any cell site irrespective of its design and location; it has no commercial political barriers to operators adopting it; and, critically, it supports frequency synchronization but also has a roadmap for time and phase synchronization.

For the next few months, Light Reading will be operating a Mobile Backhaul Synchronization Briefing Center at http://www.lightreading.com/mobile_bh where you can follow the industry’s progress on deploying 1588v2 in large-scale commercial volumes. To get started, check out these articles and analyst notes for a discussion of the challenges network operators face in deploying Ethernet backhaul and how they have finally begun pushing the technology out of trial mode and into commercial deployments:

For more a more detailed discussion of proposed synchronization standards, listen to this Webinar, hosted by Heavy Reading’s Patrick Donegan. Originally broadcast in April, it provides an excellent explanation of the key approaches and their advantages and disadvantages: These recent video clips from CTIA 2011 and Ethernet Europe also give us Donegan’s assessment of the importance of a recent Symmetricom announcement regarding 1588v2 and give us insight into how network operator BT is planning to roll out the 1588v2 standard for synchronization with its wholesale Ethernet backhaul service for operators such as Vodafone UK: A comprehensive Heavy Reading Insider report, "Ethernet Backhaul Testing: Confronting the Timing & Synchronization Challenge," which details the synchronization challenges associated with Ethernet backhaul, is also available here for purchase.

Information is also available directly from the standards bodies and interoperability forums hashing out synchronization issues. Check out these white papers:

Finally, be sure to mark your calendars for June 6 when Light Reading will present a Webinar that brings together leading vendors and network operators to discuss 1588v2 implementation. — Dawn Bushaus, Contributing Editor, Light Reading

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