Telcos mull over MPLS migration

The implementation of multi-protocol label switching (MPLS) over internet Protocol (IP) networks is a hot topic among US telecoms movers and shakers.

While vendors such as Alcatel, Juniper and Cisco displayed their wares at Supercomm in Atlanta two weeks ago, analysts disagreed on the migration path and viability of MPLS over public carrier networks.

MPLS works by tagging IP packets with information, or 'labels', that specify a route and priority. By eliminating the need for routers to look up an address for every packet, MPLS speeds packets to their destination with greater efficiency than a conventionally routed or switched network.

The obvious benefit to the corporate network manager is increased bandwidth at cheaper prices. However, the carriers will not get rich by delivering the same product in more quantity and cheaper. Increased bandwidth provisioning is merely a survival strategy.

Intelligent networks
The real advantage of MPLS to carriers and their customers is service creation. MPLS is an important stitch in the converged tapestry. By making the carrier network more intelligent, this should give network managers the ability to provision bandwidth and quality of service, and control policy - not only on their networks, but on the carrier network at the click of a mouse.

This is dependent on voice over IP convergence occurring on their networks - a trend which is beginning to occur. With an intelligent network there is no reason why network managers cannot tag their own information using MPLS. For example, a company may wish to provision a higher quality of service regarding internet connectivity for key personnel in their company.

Alcatel's main MPLS offering is the 670 RSP, a platform that integrates asynchronous transfer mode (ATM) and MPLS. The router, which promises traffic capacity from 50Gbps to five terabits, is undergoing trials with a number of vendors, such as France Telecom.

Christin Flynn, senior analyst at The Yankee Group, said: "As more service providers look to move from ATM to IP-based networks, there are several important considerations to factor into their decisions. Two pressing requirements are the ability to handle network and service management via an integrated switching and routing platform."

However, Tomas Weymouth, principal analyst at The B&W consultancy, said: "MPLS is designed to do away with the switch. This combination appears to be a contradiction."

ATM technology deployment is not slowing and is growing at a rapid rate, said Weymouth. "Carriers did not buy ATM technology as an interim solution. However, many vendors seem keen to promote this notion - while the carriers are happy with their investment in ATM. It does the job, and is something they will not be willing to discard," he added.

MPLS versus ATM
In virtual private networks (VPNs) and ISP networks, ATM appears to be losing out to MPLS. Last year UUNet deployed high-end Juniper M40 routers in its European network that support IP transmission speeds of up to 2.4Gbps and MPLS. Previously, the service provider's network both in the US and throughout Europe supported IP over ATM over Sonet using Fore Systems ASX 1000 ATM switches.

However, these will not be turned off as UUNet wants to make sure that the network is thoroughly tested. Therefore, the internet service provider is running parallel networks until the end of the year. MPLS is an immature standard and, because interoperability is a key issue, running it over a public network is complicated.

For example, Cisco's IOS (internetworking operating system) routing software supports MPLS and other VPN specific functions. But the networking company uses its proprietary Tag Distribution Protocol method for exchanging MPLS label tables among routers and switches, not the label distribution protocol (LDP) sanctioned by the Internet Engineering Task Force.

Paul Doolan, chief technology officer of Ennovate Networks and co-founder of the MPLS Forum, poured scorn on reports of carriers which claim that they are implementing MPLS on their public networks.

"Don't believe it if any tell you that they are implementing MPLS," he said. "There are a number of trials, but to my knowledge, nobody has implemented the technology wholesale."

Raj Mehta, an analyst at RHK Technologies, believes that while MPLS is not yet being implemented on carrier networks, it will be in the not-too-distant future. "We will see MPLS implementation on carrier networks, if not in the next six months, then definitely in the next 12 months," he said.

It appears that carriers are taking a softly-softly approach into the brave new world of pure IP networks, and that vendors are leading them.