The Optical Internetworking Forum (OIF) is getting some big-name support for its network-interface proposals, as international carriers and Cisco Systems Inc. (Nasdaq: CSCO) are expressing support following last week's Supercomm demonstration.

During Supercomm, the OIF convened 15 equipment companies to demonstrate interoperability using the User-to-Network Interface (UNI) 1.0 and the External Network-to-Network Interface (E-NNI). The protocols present an alternative to generalized multiprotocol label switching (GMPLS), which three years ago was supported by most large equipment vendors as a means of provisioning services across the optical network (see Optical Signaling Systems).

In a press release today, carriers lined up to show support for the OIF's efforts (see Carriers Rave About OIF Demo). Supporters included AT&T Corp. (NYSE: T), China Telecommunications Corp. (NYSE: CHA), Deutsche Telekom AG (NYSE: DT), KDDI Corp., NTT Communications Corp., Telecom Italia SpA (NYSE: TI), and Verizon Communications Inc. (NYSE: VZ).

The support is a big deal, because it means carriers can help steer the OIF's efforts to their needs, rather than having equipment vendors take guesses at what carriers want. It's the carrier support that drew Cisco into this demo, after skipping last year's UNI and E-NNI demo at the Optical Fiber Communication Conference (see OIF Demos Herald Interoperability).

"We decided to participate in this demo because of the carrier interest," says Rajiv Ramaswami, vice president and general manager of Cisco's optical networking group. "They're starting to look at whether they can do this stuff."

GMPLS, once called multiprotocol lambda switching, was envisioned as a way for service providers to provision across multiple optical networks. But the GMPLS-based "peer" model of provisioning drew some criticism, because many feared its approach left too much of the layout of a network visible to the operator. In a sense, carriers would be handing out maps of their networks to all their competitors.

That led to interest in an "overlay" model, which is what the OIF UNI represents. "The client requests services and it's up to the carrier to decide how they're activated," says Jim Jones, an Alcatel SA (NYSE: ALA; Paris: CGEP:PA) representative and chair of the OIF's architecture and signaling working group.

But it's important to note the two aren't that dissimilar. The UNI/E-NNI model uses the GMPLS protocol, the distinction being that the former can partition the network and hide chunks of it from other operators. Ramaswami contends that GMPLS could do the same thing, meaning fears of the peer model weren't always justified. "It's a myth that GMPLS can't do that without UNI. They use the same protocols," he says.

"In many ways, the OIF is a tailored version of GMPLS," Jones says.

Still, some believe GMPLS has other security issues. "Carriers are uneasy with a Layer 3 control protocol, which is susceptible to denial-of-service attacks extended to the heart of the network," says one OIF demo participant who requested anonymity.

Although Cisco was a founder of the OIF, some see its interest in the UNI as a landmark. "We're seeing a shift. Cisco has shifted [from GMPLS] to the OIF camp."

Ramaswami disagrees, noting that Cisco has always been able to support both the peer and overlay models. "I don't think positions have changed over the last two years." Cisco still sees uses for the GMPLS-based peer model, he adds, as research networks and some cable operators are interested in using it.

Although the technology has been shown to work, real deployment of the UNI/E-NNI model is "nowhere close," Ramaswami says. "There are a lot of questions regarding how to manage these things, how to do billing."

Moreover, he notes that it's still unclear whether the OIF model truly will help carriers. "I haven't seen a good business case for why a carrier should deploy a UNI approach today."

The next step for the OIF will be to complete the E-NNI routing specifications, which are being crafted in conjunction with efforts at the Internet Engineering Task Force (IETF) and International Telecommunication Union (ITU). This will bring E-NNI in line with the Automatically Switched Optical Networks (ASON) efforts within the ITU. Separately, the OIF plans to expand the UNI to include Ethernet interfaces and Sonet channels smaller than an STS1.

— Craig Matsumoto, Senior Editor, Light Reading

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