Carrier Ethernet mobile backhaul made easy

13 Jul 2009
00:00

Optimism over the ability of the mobile industry to weather the global economic turmoil varies by sector, especially on the supply side. But if you had to pick a segment with serious growth potential in the next year or two, mobile backhaul just might be it.

It\'s been understood for some time now that as mobile data traffic grows, driven by growing popularity of smartphones, USB dongles and embedded 3.5G in laptops and netbooks, cellcos face a serious bottleneck in their base station backhaul links. And with cellcos already getting selective with their capex budgets, there\'s arguably never been a better time to sink a lot of that money into backhaul upgrades.

That\'s good news for Carrier Ethernet, which has been touted for some time as the most cost-efficient technology to boost mobile backhaul links.

\'Legacy TDM and ATM backhaul transport services cannot match the scalability, much lower cost-per-bit and other packet advantages of Carrier Ethernet,\' says Michael Howard, industry analyst of Infonetics Research. The company estimates that worldwide Ethernet backhaul - whether via fiber, copper or microwave - will add over one million new or converted connections between 2009 and 2011, \'creating one of the strongest telecom market segments in the face of the world economic downturn.\'

That said, what\'s been missing from the Carrier Ethernet mobile backhaul pitch is a solid, standardized blueprint for cellcos to follow in actually deploying it. Implementing Carrier Ethernet in a backhaul network has been largely dependent on things like the legacy network technology already in place - doable but complicated.

That changed in February when the Metro Ethernet Forum released details for its Carrier Ethernet for Mobile Backhaul Implementation Agreement (IA), a.k.a. MEF 22. It\'s the first part of a two-phase plan by the MEF to make implementation of Carrier Ethernet in the mobile backhaul link relatively straightforward, regardless of legacy network technologies - not just for cellcos that want to build their own backhaul links, but also Tier 2 and Tier 3 carriers that want to wholesale Ethernet backhaul to players who don\'t have the capex budget to upgrade everywhere.

Special requirements

According to Francois Tournesac, MEF marketing co-chair and Carrier Ethernet EMEA VP of business development at Nokia Siemens Networks, MEF 22 defines the set of features needed to build mobile backhaul infrastructure with regards to legacy mobile backhaul migration, traffic separation, Ethernet OAM and packet-based synchronization. It also adds a class-of-service (CoS) mechanism, with the recommendation that cellcos adopt a minimum 2 CoS model but, ideally, a 4 CoS model that bundles traffic classes into four categories: conversational (IP- or TDM/ATM-based voice), streaming (i.e. video), interactive (web browsing) and background (non-interactive data). (See sidebar, \'MBIA: The Breakdown\')

The official MEF 22 release lists several factors that differentiate Ethernet backhaul from other Ethernet networks, such as rapid handoff between base stations. Ethernet links have to be able to keep call hops to a minimum and, of course, provide the same network protection as PDH or SONET/SDH networks. The new IA \'addresses performance and quality of service parameters, synchronization options, recovery and protection mechanisms, and Ethernet OAM services\' to meet those requirements, as well as recommendations for the network design, architecture and operation.

However, that\'s not to say that Carrier Ethernet didn\'t have standards for these functionalities already, explains Brendan Leitch at Juniper Networks.

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