Oct 17, 2005 12:00 AM,

Ethernet Evolution

By Ed Gubbins

The MEF created a uniform way for equipment vendors and service providers to manage these variations in VLAN tags, but that uniformity — crucial to achieving consistent service across different equipment and different carrier networks — came, as it often does, at the cost of added complexity. Although the MEF's system breaks down VLAN tag management into 12 basic possible scenarios, each scenario includes an array of further possibilities, creating a complicated table of instructions for equipment vendors.

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“There are 12 scenarios, but that doesn't mean only 12 solutions. It's almost exponential,” Mandeville said

Adding to the complexity is the fact that the MEF had to play within the existing framework of the IEEE's rules for VLAN prioritization. No surprise, then, that vendors had the toughest time crunching those VLAN treatment tables.

“A number of vendors had to do a considerable amount of work to make sure they'd complied to the service definitions with respect to VLAN ID preservation,” said Eric Puetz, an SBC Communications executive director and co-chair of the MEF Certification Committee. “Let's just say the vendor implementations often didn't match the book.”

If the first batch of certificates were hard to earn, the next rounds may be even tougher. At the MEF's next board meeting in early November, the group is expected to ratify MEF 14, the specifications for testing traffic management. There, the MEF will test three characteristics of an Ethernet virtual circuit: delay, delay variation and frame loss rate. These attributes are analogous to the delay, jitter and loss metrics of the “QOS” characteristics used to describe other services. A lack of sufficient QOS has long been an Achilles' heel of Ethernet.

“The MEF is trying to step in before the perception problem that happened with VoIP happens to Ethernet, trying to give legitimacy to the technology,” said Michael Arden, principal analyst with ABI Research, which predicts this year's $336 million carrier Ethernet equipment market to grow 81% annually through 2010.