Double standard

Vendors take stance on MPLS standards Multiprotocol label switching has quickly turned into a standard requirement to enable IP services such as virtual private networks. But having MPLS in just one place in the network doesn't mean a service provider can deliver advanced IP services; the protocol must be in multiple spots, including the edge and the core. That's where standardization comes into play. MPLS-enabled equipment from different vendors must be interoperable if those reputed services are to become general issue from service providers.

Currently, the Internet Engineering Task Force is in the process of ratifying MPLS standards with the backing of equipment providers such as Cisco Systems and Avici Systems. In addition, a separate body, the MPLS Forum, has formed with its own goals for interoperability and education. While the two groups might seem compatible, there is some contention among members and non-members about the focus of the MPLS Forum and its benefits to the overall MPLS effort.

MPLS makes the interworking of IP and ATM possible within the same networking environment. The existence of services such as scalable and flexible VPNs hinges on MPLS. In addition, the protocol allows service providers to deliver frame relay, leased line and Internet dial-up services while simultaneously delivering VPNs, managed intranets and extranets, voice over IP, Web hosting and e-commerce applications using one platform.

To combat the network overlay problem and the associated costs and overhead that comes with doing IP over ATM, equipment vendors developed MPLS, which enables new control planes within switches to replace ATM control planes. Though ATM control planes could read and switch packets using labels, the ATM control planes could not switch and route on the level required by IP services, said Rob Redford, senior director of marketing for Cisco. "MPLS complements ATM so that the two networks are transparent to each other," he said. "The ATM switch [now] makes the same decisions that the router would make."

Originally, the IETF considered several competing technologies based on tag switching. The forum chose a standard and now is completing the last step in the process, Redford said.

Meanwhile, a group of vendors and service providers formed the MPLS Forum to advance MPLS deployment and technologies. Founding members include Marconi Communications, Qwest Communications and BroadBand Office.

The MPLS Forum, founded less than a year ago, set out to accomplish two goals: educate the market about MPLS and push for interoperability between equipment vendors, said David Drury, president and chairman of the MPLS Forum and vice president of technology strategy for Marconi.

"The IETF is not a training organization," he said. Nor does it deal with interoperability. "We did not form with the intent to replace the standards body."

But detractors see the MPLS Forum as a hindrance to acceptance, saying the forum will slow the process for finalizing and deploying standards. Avici has not yet joined the forum, waiting instead to see how providers would participate, said Dave Caplan, product line manager for Avici. "That's really what drives the effectiveness of the forum," he said. "Otherwise these forums are often used to drive wedges in product direction. We are very involved in the IETF, and clearly all the developments and discussions in MPLS are being driven by the IETF today."

Avici does not have any "philosophical opposition" to the MPLS Forum's charter, Caplan said. "It's just a question of spreading our resources too thin... and keeping up with the pre-standards." The company is watching the MPLS Forum to see if the service provider membership grows and if its customers are among them, he added.