The carrier has 40G Ethernet services on its five-year road map but no specific deployment dates, says Jeff Schwartz, Group Manager, Global Ethernet Product Marketing. Instead, Verizon Business has more 10G Ethernet access services on tap for later this year.
"We want to get to 100G," Schwartz says. "40G may be an intermediary step."
Once Verizon Business moves its backbone architecture towards 40/100G, products and services will be following, he says.
Spirent Communications, a maker of Ethernet testing gear, plans to release a 40G Ethernet testing module in the second half of this year, and 100 Gigabit Ethernet modules in early 2010, says Tim Jefferson, general manager of the converged core solutions group at Spirent. Jefferson says one of the caveats that users should be aware of as they migrate from 10G to 40/100G Ethernet is the need to ensure precise clocking synchronization between systems -- especially between equipment from different vendors.
Imprecise clocking between systems at 40/100G -- even at 10G -- can increase latency and packet loss, Jefferson says.
"This latency issue is a bigger issue than most people anticipate," he says. "At 10G, especially at high densities, the specs allow for a little variance for clocks. As you aggregate traffic into 10G ports, just the smallest difference in the clocks between ports can cause high latency and packet loss. At 40G, it's an order of magnitude more important than it is for 10G and Gig.
"This is a critical requirement in data centers today because a lot of the innovations going on with Ethernet and a lot of the demand for all these changes in data centers are meant to address lower latencies," Jefferson adds.
Another challenge is readying the cabling infrastructure for 40/100G, experts say. Ensuring the appropriate grade and length of fiber is essential to smooth, seamless operation, they say.
"The big consideration is, what's a customer's cabling installation going to look like and what they're looking for to be able to handle that," Booth says. "They are probably going to need to have a parallel fiber capability."
"The recommendations we're making to customers on their physical plant today are designed to take them from 1G to 10G; 10G to a unified fabric; and then address future 40G," Cisco's Gourlay says.
The proposed physical interfaces (PHY) for 40G Ethernet include a range to cover distances inside the data center up to 100 meters, to accommodate a range of server form factors, including blade, rack and pedestal, according to the Ethernet Alliance. The 100 Gigabit Ethernet rate will include distances and media appropriate for data center, as well as service provider interconnection for intra-office and inter-office applications, according to the organization.
The proposed PHYs for 40G Ethernet are 1 meter backplane, 10 meter copper and 100 meter multimode fiber; and 10 meter copper, 100 meter multimode, and 10 kilometer and 40 kilometer single-mode fiber for 100 Gigabit Ethernet.