MPLS facing slow adoption, despite flurry of market hype

Part Two: MPLS readies networks for user boom | Part Three: MPLS lays foundation for new VPN services

Backers of Multi-protocol Label Switching have hailed the technology over the past five years as a key enabler of Internet scalability and a harbinger of new services, such as advanced IP VPNs. MPLS makes IP as reliable, predictable and navigable as ATM and frame relay, they say.

Despite the promise, cost-conscious service providers have been cautious about embracing the technology for fear of cannibalizing their bread-and-butter services.

"There's definitely the Release 1.0 problem," says Mark Tharby, a vice president at Nortel, which has plans to support MPLS across its equipment line. "It's never a good idea to aggressively [embrace] a 1.0 release of any kind of new architecture."

While MPLS has received strong support from carriers such as AT&T and Equant, observers say its success may hinge on its adoption by the regional Bell operating companies because the balance of power in the telecom industry is shifting toward them.

To date, the Bells are largely at the trial stage with MPLS.

MPLS has its roots in Ipsilon's IP Switching, Cisco's Tag Switching, IBM's ARIS technology and a few other proposals to bring the sort of traffic engineering found in connection-oriented ATM and frame relay networks to connectionless IP networks. The idea is to steer IP traffic onto a variety of routes instead of the single one discovered by an interior gateway protocol such as Border Gateway Protocol, to avoid congestion or failures, or to enable a particular class of service or guaranteed service level.

MPLS switches and routers affix labels to packets based on their destination, type-of-service parameters, VPN membership or other criteria. As a packet traverses a network, other switches and routers build tables associating packets and routes with labels. The MPLS switches and routers - dubbed label switch routers - assign each packet a label that corresponds to a particular path through the network.

All packets with the same label use the same path - a so-called label switched path (LSP). Because labels refer to paths and not endpoints, packets destined for the same endpoint can use a variety of LSPs to get there.

With all the interest and alternative proposals for IP traffic engineering, the Internet Engineering Task Force started an MPLS working group in 1997. Core specifications for MPLS were defined about a year ago.

Vendors, service providers and analysts say MPLS is about 75% to 80% baked, with work still outstanding on MPLS-to-ATM/frame relay interworking and quality of service (QoS), among other things.

Who's on board?

Currently, there are about 30 carriers and service providers implementing or planning to implement MPLS, according to an unofficial tally by the MPLS Forum, an international body formed in early 2000 to accelerate the adoption of MPLS and create implementation agreements drawn from standards work. Separately, Cisco says it has more than 80 MPLS customers, while Juniper and Unisphere say they have 10 or less apiece.

Interestingly, the MPLS Forum list does not include any of the RBOCs on its list, a point not lost on analyst Tom Nolle, president of consultancy CIMI Corp. and a Network World columnist.

"The watershed for MPLS [will be] the RBOC regional network buildouts that will start next year," Nolle says. "If MPLS has the ability to play a role in those buildouts, that frames MPLS in a commercially successful context and pretty much assures it becomes more widespread as a standard. If it can't play a role, then it's going to be much harder for any kind of significant MPLS evolution to take place."

SBC Communications will run an MPLS-enabled optical Ethernet trial next year using a single vendor's equipment, says Christopher Rice, a senior vice president for the carrier. Rice does not envision MPLS scaling throughout SBC's network until late 2003 or early 2004, when vendors can prove interoperability between their gear.

For corporations, MPLS will enhance the QoS of optical Ethernet virtual LAN services, Rice says. MPLS is also vital in ensuring toll-grade quality of softswitch-based packet telephony networks.

"MPLS is a key element," Rice says. "It just has to truly have interoperability or it's really not effective."

A year ago, BellSouth released plans to use MPLS in a Miami network access point (NAP). The RBOC says that will happen in the first quarter of next year. The NAP links data traffic between the U.S., Latin America, the Caribbean, Africa and Western Europe. MPLS will allow the NAP to support next-generation multimedia applications such as voice and video over the Internet, BellSouth says.

MPLS will also allow additional network capacity to be turned up automatically at the NAP, where the carrier says traffic demand doubles every two to three months.

BellSouth is also looking to migrate its ATM/frame relay and circuit-switched core to MPLS for cost reduction and operational efficiencies. The RBOC also may offer an MPLS-based VPN service, but company officials would not say when.

Verizon did not return phone calls by press time. Qwest Communications, which acquired RBOC US West, is one of the 30 carriers on the MPLS Forum list implementing or planning to implement MPLS.

Among interexchange carriers, AT&T was one of the first carriers to employ an MPLS-based service. AT&T's IP-Enabled Frame Relay and IP-Enabled ATM services use MPLS to construct private tunnels for IP VPNs across the carrier's existing frame relay and ATM transport infrastructures.

"The future is tied to being able to provide customers VPN solutions," says Tim Halpin, AT&T's director of frame relay and ATM services. "Especially on our frame and ATM private network-based VPNs, MPLS is critical to that. By doing label switching, I can minimize the amount of IP lookups that are done. . . . I can minimize the amount of latency that that application adds to the transport service."

There's much discussion in the industry that MPLS will eventually replace ATM and frame relay as the core of a multiservice - voice, video and data - infrastructure. Lucent, the leading vendor of ATM switches to service providers, for example, killed its next-generation ATM core switch in order to get an MPLS-based switch to market faster to meet the demand among its customers.

Established and start-up companies, including Equipe Communications and WaveSmith Networks, are developing next-generation ATM/frame relay switches with a migration path to IP/MPLS.

But Halpin warns that frame relay and ATM provide four things that IP/MPLS currently cannot: highly reliable transport; guaranteed performance; low latency; and security.

"By layering a VPN on top of frame, I inherit all of those characteristics of frame," Halpin says. "Don't tell me you're going to kill frame unless you can deliver those same kinds of things, or better."

A slow migration

Equant sees the transition of ATM/frame relay to MPLS happening in much the same way that customers migrated from X.25 to frame relay - gradually, over several years.

"Most of the new customers will be more and more implemented on IP VPN and not frame," says Guillaume Boudin, director of Equant's IP product line. "Lots of existing customers will be progressively migrated from legacy data services to IP VPN. But some of them will also probably remain on those data services for a while."

Equant has 400 subscribers in 140 countries for its MPLS-based IP VPN service. MPLS' traffic engineering capabilities are also helping Equant scale its IP backbone, Boudin says, and Equant is considering using MPLS traffic engineering next year to further fine-tune service-level agreements on its existing prioritized class- and quality-of-service IP VPN features, or to introduce new differentiated services.

But the progress made by carriers such as Equant and AT&T in MPLS is the exception, not the rule, says Bob Bellman, president of consulting firm BrookTrail Research.

"It's all new and semi-unproven, so carriers are taking their time," he says.

Next week: The benefit of MPLS traffic engineering.

Contact Edge Managing Editor Jim Duffy

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