Last Call for Sonet/SDH?

Minus a few details such as monitoring and management, Ethernet is ready to take over carrier networks, according to the latest Heavy Reading report. The report, Sonet/SDH-to-Ethernet Migration Strategies, surveyed major carriers worldwide, finding many of them have halted growth of the Sonet/SDH network and are ready to move to packets.

"Sixty percent of operators polled indicated they had already begun moving from Sonet/SDH to Ethernet, or would begin to do so in 2006," writes chief analyst Scott Clavenna. "The deployment of Ethernet-based transport gear to support new services and overall carrier network packetization will create a new class of Ethernet optical transport networks (EOTNs)."

Non-telcos -- greenfield carriers without legacy-network baggage -- would seem the best candidates for an EOTN. Clavenna cites Google (Nasdaq: GOOG) and Yahoo Inc. (Nasdaq: YHOO) as candidates for such a network, and Google might already be building one. (See Google's Own Private Internet.) But it's the major telcos and cable companies that are driving the concept.

"In the past year, larger operators have made strong indications that as they have embarked on voice packetization and the convergence of data services around IP, it may soon follow that their transport networks will need to become more packet-aware," Clavenna writes.

Ethernet is the obvious candidate for that packet transport. Carriers told Heavy Reading that the biggest drivers of new metro optical buildouts are business Ethernet services and triple-play services -- both of which already use Ethernet as the transport layer.

The trend is affecting the vendors that tailor to the "converged network." The multiservice provisioning platform (MSPP) reportedly is morphing into more of a packet-transport box, putting less emphasis on its Sonet/SDH roots. (See Level 3, XO Rethink MSPPs and Ethernet Stalks the MSPP.)

That the major telcos are interested in this equipment "favors incumbent MSPP vendors in most cases," Clavenna writes, citing Alcatel (NYSE: ALA; Paris: CGEP:PA) as being well positioned "thanks to its success in supplying broadband access solutions."

So, great plans are afoot, but Ethernet faces the same problem as always: performance. Carriers are loathe to give up their Sonet/SDH monitoring and management capabilities, and Ethernet technologies such as circuit emulation -- which aims to make packet networks perform more like circuit-oriented Sonet/SDH ones -- aren't yet ready to pass muster.

"Circuit emulation, though advancing in sophistication, continues to concern operators and limit their enthusiasm for transitioning fully to Ethernet optical transport," Clavenna writes. "Most operators believe Ethernet will in fact catch up soon, but standards work must be completed, performance demonstrated, and interoperability proven."

— Craig Matsumoto, Senior Editor, Light Reading