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VPLS Standard DebatedVPLS Standard Debated

Virtual Private LANs could be a hot offering, but first comes consensus from equipment providers

November 27, 2002

5 Min Read
VPLS Standard Debated

Virtual private LAN services, which extend the corporate Ethernet network over a carrier’s wide area network, are expected to gain momentum among service providers in 2003. But vendors will first have to get behind one of several Internet Engineering Task Force (IETF) standards drafts before service providers will adopt the technology in any big way.

“It’s important for vendors to rally around some draft of a standard,” says Kevin Mitchell an analyst with market research firm Infonetics Research Inc. “Today’s carrier networks are multivendor, and interoperability is very important. Even with standards in place, that isn’t easy to achieve, but it’s a start.”

According to a recent Infonetics study, 32 percent of carriers are already offering virtual private LAN services. By the end of next year, 47 percent say they expect to be offering them. The study, called Service Provider Networks: Access, Routing, Switching, and Optical, US/Canada 2002 asked 20 carriers which access technologies they are deploying now or will deploy in the next 12 months.

“It’s a positive change, but not overwhelming,” says Mitchell about the results. He says the uncertainty in the standards process could be one reason that more carriers are not bullish on deployments of VPLS for next year.

But the study found that carriers are deploying and plan to deploy more simple point-to-point Layer 2 Multiprotocol Label Switching (MPLS) Virtual Private Networks (VPNs). These are VPNs that use Frame Relay or Asynchronous Transfer Mode (ATM) as transport, instead of the Ethernet used in VPLS. Fifty-three percent say they offer that service today, and 74 percent say they expect to be offering it by late 2003.

These results aren’t too surprising, on two fronts. For one, many carriers plan to continue leveraging their existing Frame Relay and ATM networks. And secondly, the standards process is more mature for point-to-point or circuit-based Layer 2 MPLS VPNs. There are currently two IETF drafts to support these circuit-based VPNs (see Juniper/Cisco Duke It Out Over MPLS). These include the "Martini Draft," named after its author Luca Martini of Level 3 Communications Inc. (Nasdaq: LVLT), which uses Label Distribution Protocol (LDP) signaling to establish point-to-point connections throughout the network.

The other Layer 2 VPN draft comes from Kireeti Kompella, an engineer at Juniper Networks Inc. (Nasdaq: JNPR). This draft uses the Border Gateway Protocol (BGP) common in routed networks for signaling. While Juniper claims that Draft Kompella scales better than Martini, most vendors have standardized on Martini.

The standards situation is a bit stickier when it comes to VPLS. Because Ethernet by nature is not point-to-point, Draft Martini alone is not sufficient. Currently, there are several IETF drafts being debated in the Provider Provisioned Virtual Private Networks working group. Over the past several months, vendors have begun choosing sides in the standards face-off, and it appears that most are rallying around one of two proposals: The "Lasserre-V. Kompella" draft, which extends the use of LDP for signaling defined in Draft Martini; or the original Kompella Draft proposed by Juniper.

Marc Lasserre of Riverstone Networks Inc. (Nasdaq: RSTN) and Vach Kompella of Timetra Networks (who happens to be the brother of Juniper engineer Kireeti Kompella) are the two main authors of Lasserre-V. Kompella. So far, the draft has gained official support from engineers at:

Other vendors like Foundry Networks Inc. (Nasdaq: FDRY) are already supporting features in the Lasserre-V. Kompella draft, says Chandra Kopparapu from Foundry. The company demonstrated its capabilities in an interoperability demonstration at the Networld + Interop show in Atlanta back in September (see Foundry Takes Part in VPLS Test).

“The Lasserre-V. Kompella draft falls more easily around current Ethernet switching technology,” says Paul Joseph, a product manager at Force10 Networks Inc.. “Companies like us, Cisco, Extreme, Riverstone, Foundry, Timetra -- we are all leaning towards the Lasserre-V. Kompella draft, because we have no problem manipulating Ethernet packets.”

The other draft proposed for VPLS is the original Kompella Draft from Juniper.

“The sweet spot for Layer 2 MPLS VPNs deployments seems to be in using them to complement Layer 3 MPLS VPNs. Like RFC 2547, Kompella also uses BGP, so it’s an easy fit,” says Kevin Dillon, director of portfolio marketing at Juniper.

Dillon says that LDP requires much more manual configuration from service providers when adding new nodes to the network. More manual configuration means more cost, he notes. Using BGP is simpler.

“That is true,” says Force10's Joseph. “But a lot of service providers are nervous about deploying BGP because the protocol itself is so complicated. They’d rather use a simpler protocol even if it means more manual intervention.”

Technology aside, the debate will be resolved by politics and market share. The Lasserre-V. Kompella draft already has two things working in its favor: It has support from incumbent carriers like SBC, which has three engineers officially supporting the draft; and it also has support from Cisco, the number one player in the Ethernet switching market. With endorsements like these, it’s difficult to bet against it.

— Marguerite Reardon, Senior Editor, Light Reading
www.lightreading.comWant to know more? The big cheeses of the optical networking industry will be discussing service trends at Lightspeed Europe. Check it out at Lightspeed Europe 02.

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