Startup emerges from stealth mode to demo its 10-Gbit/s Ethernet-over-RPR solution at the Comnet tradeshow

January 29, 2002

3 Min Read
Corrigent Comes Out

WASHINGTON, D.C. -- Yet another vendor touting resilient packet ring (RPR) technology is aiming to make a splash at the Comnet tradeshow today, with a live demo of 10-Gbit/s Ethernet metro gear achieving sub-50-millisecond restoration times (see Corrigent Demos 10-Gig RPR).

The company, Corrigent Systems is showing its CM-100 transport platform for the first time. The box carries Ethernet traffic while also providing the full range of existing TDM (time-division multiplexing) and Sonet-based services at 10 Gbit/s, according to Corrigent, which claims that it can do this for half the cost of alternative solutions.

What differentiates Corrigent’s new product from the dozens of other players in the RPR market is that the product supports a full implementation of Sonet and is specifically designed to help tier-one service providers migrate their networks from circuits to packet networks.

Other solutions like those from Lantern Communications Inc. and Luminous Networks Inc. are based on Ethernet, while Cisco Systems Inc. (Nasdaq: CSCO) uses RPR for its router interfaces. But Corrigent has taken a different approach. It uses Sonet as the physical layer to take advantage of the timing mechanism inherent in the Sonet protocol. This allows the sub-50-millisecond restoration. Then it uses the RPR MAC for resilience, with Ethernet or another packet service layered on top.

Unlike other solutions that carry Ethernet over Sonet, Corrigent is not encapsulating the Ethernet traffic. Instead, it is able to carry native Ethernet over RPR over Sonet, making for more efficient use of bandwidth, says Gady Rosenfeld, director of strategic marketing for Corrigent.

It’s the use of the Sonet physical layer in combination with RPR that allows Corrigent to carry time-sensitive and jitter-sensitive traffic like voice and also allows the device to be deployed within a Sonet infrastructure. As a result, the company asserts, service providers can have all the features of Sonet without allocating a spare fiber for protection. Rosenfeld says it can save providers anywhere from 50 to 80 percent on operating costs.

“A lot of the players have been pushing a next-generation approach,” says Dave Dunphy, an analyst with Current Analysis. “But Corrigent doesn’t seem to be taking that tack. They’re offering a transition by supporting a broad range of traffic types.”

But Corrigent isn’t the only RPR vendor claiming to have the flexibility to handle Sonet/TDM traffic. Luminous Networks Inc. also supports Sonet/TDM traffic. Luminous differs from Corrigent in two main ways. One, its architecture does not use the Sonet physical layer; it uses Ethernet. Second, it only handles 2.5-Gbit/s rings in its current version, whereas Corrigent handles 10-Gbit/s rings with an architecture that scales to 40 Gbit/s.

”Ten Gbit/s is certainly an important factor,” says Dunphy. “It’s starting to become more and more important to providers.”

While Corrigent may outperform Luminous on speeds and feeds right now, Luminous has one big advantage over Corrigent. It is actually shipping its product to real live customers. Cox Communications Inc. (NYSE: COX) is deploying the Luminous product under the Scientific-Atlanta Inc. (NYSE: SFA) label. Luminous also announced earlier this month that China Netcom Corp. Ltd. has deployed its PacketWave in nine cities, with three city rollouts planned for later this year (see Chinese Get Luminous). Corrigent’s CM-100 hasn’t even shipped for beta testing yet.

Corrigent executives say it should be ready for general availability no later than the middle of this year. And unlike other RPR companies, which are still working out the terms of certification with Telcordia Technologies Inc., Corrigent claims it will be fully Osmine compliant by September of this year.

Corrigent, like startups Luminous and Lantern, has been very active in the RPR working group, helping draft the Darwin proposal that was recently accepted by the group (see RPR Moves Forward). This trade show marks the first time the company has exhibited in public (see Corrigent Joins Metro Ethernet Mix).

— Marguerite Reardon, Senior Editor, Light Reading

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