VPLS slowly pushing out legacy networks

Legacy data services such as frame relay and ATM will eventually become obsolete, but users will not have to give up on Layer 2 networking in order to make the transition to IP VPNs.

They do need to be patient, however.

A handful of providers, including Broadwing and Masergy, are offering Virtual Private LAN Service (VPLS), while others, such as AT&T and Verizon Business, have tests under way.

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Legacy data services such as frame relay and ATM will eventually become obsolete, but users will not have to give up on Layer 2 networking in order to make the transition to IP VPNs.

They do need to be patient, however.

A handful of providers, including Broadwing and Masergy, are offering Virtual Private LAN Service (VPLS), while others, such as AT&T and Verizon Business, have tests under way.

VPLS lets customers maintain control over their routes, much as they do with frame relay, but move their traffic to a fully meshed MPLS network. This Layer 2 technology, based on IETF draft specifications, is viewed as the logical migration path for legacy frame relay users.

Yet it is not widely available.

Last year AT&T said it would offer nationwide VPLS in the first half of 2006, but the company won't confirm that timetable - or any timetable - today.

AT&T has VPLS available in the 20 metropolitan markets where SBC had been offering it before the merger of the two companies. Yipes is another service provider that offers VPLS locally in 14 metropolitan markets.

"We're looking at how to integrate [the metropolitan VPLS offer] into our overall VPN portfolio," says Burt Winter, executive director of MPLS VPN services at AT&T. "VPLS is not more difficult than any other technology. It's a matter of timing. It was only a matter of going into the merger and having different investment priorities. We have no vendor problems or issues."

AT&T also reiterated that it has no plans to shut down its frame relay or ATM backbones, saying it is continuing to make investments in both networks.

Last year Sprint was the first of the big three frame relay service providers to reveal its plans to shut down its legacy data networks. Sprint says it's on target with its plan to shut down these networks in 2009. "We're seeing a much better adoption of IP-based services. We had a target in mind to measure IP service adoption, and we doubled that," says Karen Emery, manager for data product simplification at Sprint.

Sprint has no plans to introduce VPLS, but it does have a Layer 2 alternative. The service provider has been offering customers its SprintLink Layer 2 service for three years. The service is based on Layer 2 Tunneling Protocol, an IETF draft specification.

Despite the fact that Sprint has a mature Layer 2 alternative, Emery says the majority of legacy frame relay customers are moving to Layer 3 MPLS IP VPN services, not Sprint's Layer 2 service.

Verizon Business also says it has no plans to shut down its legacy data networks. But the service provider says it is testing two Layer 2 services and will begin customer trials in the third and fourth quarter.

Verizon plans to roll out a service called Private IP Virtual Private Wire Service. The service uses an IETF specification that spells out how to aggregate frame relay and ATM access circuits, and encapsulate them for transport over an MPLS core on a point-to-point basis.

The service provider also is planning a customer trial of its Private IP VPLS in the fourth quarter. Mike Marcellin, director of IP Ethernet networking at Verizon Business, says commercial services are expected to be available the quarter after each trial begins.