IEEE Tunes Ethernet for Telcos
This was a big week for the emerging resilient packet ring (RPR) technology, a new protocol that will allow metropolitan area service providers to create high-speed, survivable ring networks designed for Internet protocol (IP) and other packet data.
Why should you care? It means the equipment vendors are getting serious about providing standards for packet-based data services that also deliver the fault tolerance of older ring technologies such as Sonet.
The Institute of Electrical and Electronics Engineers Inc. (IEEE) Resilient Packet Ring (RPR) working group 802.17 hosted its first official meeting on Tuesday and Wednesday in California. And a group of vendors -- including Cisco Systems Inc. (Nasdaq: CSCO), Dynarc, Lantern Communications, Luminous Networks Inc., and Nortel Networks Corp. (NYSE/Toronto: NT) -- announced on Monday the formation of the Resilient Packet Ring Alliance to support the standardization and market adoption of RPR (see Resilient Packet Ring Alliance Formed).
In a nutshell, resilient packet ring technology provides Ethernet and other packetized transport the same kind of protection and resiliency found in Sonet rings. Ethernet is a point-to-point technology. This means that when the network is set up in a ring, as nearly 80 percent of metro networks are, traffic moves in only one direction. When an Ethernet connection is interrupted, packets must time out before they are retransmitted -- a process that can take seconds.
But Sonet is different. Traffic can move around the ring in both directions, which means connections can be restored much faster if there is an interruption. Why not stick with Sonet? Because it’s not optimized for data and is more expensive than Ethernet.
This is where RPR comes in. Layered on top of Ethernet, it provides the best of both worlds: Sonet-like protection at Ethernet prices.
The standard is still in its earliest days, but at least four vendors, including Dynarc, Cisco, Luminous and Nortel, claim they are shipping products with RPR-like features. And another routing company, Riverstone Networks, announced this week that it will support the feature on its latest metro router, the RS 38000 (see Riverstone Scores a Coup).
So far, discussion within the working group and the RPR Alliance has been amicable, according to those who were at the meetings. But as the standards process plods on, controversy is liable to surface.
“From what I have seen, people are pretty much resigned to the fact that there will be trade-offs in various proposals,” says Patrick Conlon, VP of business development for Dynarc. “But I’m sure as we get further along, there will be some debate, even though the current commercial products are already implementing most or all of these features.”
The next IEEE working group meeting will be held in March in North Carolina. A full standard isn’t expected to be adopted for at least nine months.
-- Marguerite Reardon, senior editor, Light Reading, http://www.lightreading.com