Ethernet exodus

AS CARRIERS DEPLOYED MORE AND MORE Ethernet in private customer networks over the last several years, it became clear that this fast, simple and high-bandwidth technology would eventually permeate their own infrastructures. Networks based on IP and MPLS in the core and Ethernet downstream became the consensus blueprint among North American carriers. Less clear, however, was exactly how carriers would transform existing networks into those new ones. Or at what pace. Or how they would navigate the pitfalls in the migration path. Carriers are still feeling their way along that path.

At Globalcomm 2006 in Chicago in June, Alcatel and Lucent Technologies both introduced the latest equipment promising to help carriers migrate to Ethernet from legacy time-division technology such as Sonet. Alcatel's 1850 Ethernet transport switch (which had already been available outside the U.S.) and Lucent's Universal Packet Mux both boasted hybrid switch fabrics, adjustable by carriers to any mix of Sonet and Ethernet (among other technologies).

Carriers with their eyes on Ethernet would no longer need to map it onto Sonet in order to switch it through a multiservice provisioning platform (MSPP), the vendors assured. This gear would allow traffic to stay in its native form, while adapting its hybrid switch fabric like a chameleon changes color. Carriers could transform their networks to pure Ethernet at their own pace, the vendors said.

“[The 1850] is really a step in the right direction of where we're headed to, which is multiprotocol interfaces and fabric that can support all of them, with wavelengths going out,” said Eve Griliches, research manager for IDC. “The next generation is really the [reconfigurable optical add/drop multiplexer] but fill it with Sonet and Ethernet interfaces.”

It's unknown how quickly carriers will move in that direction, however. “The real-life migration may be two to three years after the ‘trade show migration,’” said Peter Kjeldsen, research director for Gartner Dataquest Research.

Despite the circuit-or-packet versatility of today's MSPPs, the vast majority of interfaces employed on them now are yesterday's plain old Sonet. According to Ovum-RHK, only 14% of last year's Sonet MSPP ports were Ethernet, though the research firm expects that number to rise to 46% by the end of the decade.

Whether measured in ports or revenue, about half of today's Ethernet services are delivered over fiber, with an Ethernet switch at either end, according to Ovum-RHK. Only 20% of Ethernet service ports (25% in terms of revenue) come from MPLS gear. But by the end of this decade, those numbers will trade places, with MPLS gear serving half the market and Ethernet-over-fiber relegated to a quarter or less.