Nortel Pipes SANs Into Sonet

Preps FC-over-Sonet options for more cost-effective and longer-haul optical SAN extensions

March 26, 2003

4 Min Read
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Nortel Networks Corp. (NYSE/Toronto: NT) plans to roll out Fibre Channel-over-Sonet options for its metro optical networking platforms starting next month -- promising more cost-effective ways to extend SANs over much longer distances (see Nortel Preps Storage Over Sonet).

As first reported by Byte and Switch, Nortel will broaden its OPTera Metro platforms to support storage over Sonet to provide enterprises and carriers lower bit-rate connectivity options at distances of up to thousands of kilometers (see SANs See Sonet).

In April, Nortel expects to ship two-port GFP (Generic Framing Procedure) cards for its OPTera Metro 5100 and 5200, which will allow those systems to encapsulate Fibre Channel, Ficon, or Gigabit Ethernet into Sonet frames. Then in July, it will follow on with the same options for its lower-end 3500 platform. No pricing is available yet for the storage-over-Sonet options.

Today, most companies extend SANs over long distances by converting Fibre Channel to IP, says Jack Hunt, director of marketing in Nortel's optical storage connectivity division. But this approach introduces some latency -- which can be murder on storage applications.

"Sonet is connection-oriented, so you don't have the jitter and delay issues you get with a routed, connectionless architecture," he says. Hunt also notes that the cores of many service provider networks are running Sonet, so sending storage over Sonet eliminates that additional step of encapsulating it into IP.Nortel already enjoys a healthy lead in the market for storage over DWDM (dense wavelength-division multiplexing), with IDC estimating that it has around 80 percent share of this segment. DWDM provides high bandwidth, but requires access to dark fiber and is generally limited to distances of around 200 km.

Sonet, by comparison, is ubiquitous, with an estimated 135,000 Sonet rings in North America alone, and can extend up to 10,000 km. "Fibre Channel is well established and Sonet is also well establishes," says James Opfer, an analyst at Gartner Inc. "It seems to be a very good meeting of technologies." (See our recent reports, Storage Over Optical and Making Sonet Storage-Friendly.)

However, Nortel's FC-over-Sonet interfaces will run at 1-Gbit/s -- even though the Fibre Channel industry has almost completely made the transition to 2-Gbit/s switches. Hunt maintains this isn't a huge drawback: First, 2-Gbit/s FC equipment is backward-compatible with the 1-Gig standard. Anyway, he says, most customers who adopt storage over Sonet will run at 1 Gbit/s or less. "To be honest, within the metro, once you get to 2-Gbit/s, people look to DWDM," he says.

Nortel will join several other vendors that already have offerings in this emerging space, including Akara Corp., Alcatel SA (NYSE: ALA; Paris: CGEP:PA), LightSand Communications Corp., and Lucent Technologies Inc. (NYSE: LU) (see SGI Elongates File System and EYT Waves In Optical SAN Service). Meanwhile, Cisco Systems Inc. (Nasdaq: CSCO) says it's also working up FC-over-Sonet plans, slated for delivery in the second half of 2003.

In the near term, Nortel sees a major carrier play for its storage-over-Sonet technology. Hunt says the company is working with "five or six" carriers in North America -- none of which he would name -- in various stages of deploying or planning storage-over-Sonet services based on the Nortel gear."Carriers can put the FC-over-Sonet blades in their OPTera Metro 3500 and offer a tariffed Fibre Channel service," he says. "That's where we see the sweet spot. Midsize enterprises don't want to run their own Sonet network." Hunt expects service providers to announce services on this front starting in the third quarter of 2003.

The company has tested its FC-over-Sonet technology with SAN switches from Brocade Communications Systems Inc. (Nasdaq: BRCD) and McData Corp. (Nasdaq: MCDTA), and it is currently in the process of certifying it with storage arrays from EMC Corp. (NYSE: EMC), IBM Corp. (NYSE: IBM), and Sun Microsystems Inc. (Nasdaq: SUNW), according to Hunt.

Opfer says lining up partners will be critical for Nortel. "You can't bring this to market without partners," he says. "You need someone who can assure customers that it all works."

Todd Spangler, US Editor, Byte and Switch

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