Optical/IP Networks

Tellium's Optical VPN: What Is It?

Yesterday, Tellium Inc. (Nasdaq: TELM) claimed to be the first optical switch company to offer optical virtual private network (VPN) functionality (see Tellium Debuts Optical VPN).

Interesting -- but what exactly does it mean? Tellium says the new product, called the StarNet Optical-VPN, will let carriers partition their optical networks into virtual pipes, offering customers the look and feel of their own private optical networks. The technology will ship with Tellium's StarNet Optical Services, a management software package that comes with Tellium's Aurora Optical switches.

Some analysts say the advantage of an optical VPN is that it could allow carriers to save money in delivering optical circuits.

"It's an interesting concept," says Scott Clavenna, president of PointEast Research LLC and director of research at Light Reading. "VPNs are a way to improve the utilization of the network. They're much cheaper than individual leased circuits, since you are able to take advantage of the shared resources."

In general, VPNs are a hot topic. Carriers left and right are announcing IP VPN services based on Multiprotocol Label Switching (MPLS), IPSec, and other technologies (see Service Providers Jump on VPNs). The promise of a VPN is that it will make carrier networks more efficient by allowing multiple users to use common network resources, in addition to enabling carriers to offer new revenue-generating services. With the introduction of Tellium’s StarNet O-VPN, the concept seems to be sliding down the Open System Interconnection model (OSI).

At a concept level, optical VPNs and IP VPNs share similarities, but they do have some essential differences. For one, they work at different layers of the networking stack. Optical technology works at the physical layer, while Internet Protocol (IP) is a network-layer technology. This means that IP VPNs carve up the actual data packets in the pipes, which requires encryption and tunneling, but optical VPNs simply carve up wavelengths in a circuit. In this way, optical VPNs are much more like a Asynchronous Transfer Mode (ATM), TDM (time-division multiplex), or Frame Relay service.

Currently, optical grooming switches already slice and dice wavelengths, multiplexing and demultiplexing them into smaller and larger pipes. But what has been lacking is the ability to allocate different OC48 (2.5 Gbit/s) wavelengths to different customers with a guaranteed performance rate. Also lacking in most optical switches is the ability for a service provider’s customer to self-provision a service.

Now Tellium’s software allows a service provider to carve up a single OC192 (10 Gbit/s) pipe and allocate one OC48 wavelength to one customer and another OC48 wavelength to a different customer. Each of the OC48 wavelengths in the OC192 pipe are treated as separate networks and securely partitioned from the other wavelengths for the duration of the transmission.

The benefit of Tellium’s optical VPN functionality is that it allows service providers to generate new revenue by offering service-level agreements and managed services. It also allows carriers to save on operational costs by allowing end users to self-provision their networks.

Tellium claims to be the first vendor to announce a product dedicated to optical VPNs, but it isn’t the first to talk about the concept. Ciena Corp. (Nasdaq: CIEN), Lucent Technologies Inc. (NYSE: LU), and Nortel Networks Corp. (NYSE/Toronto: NT) have all touched on the idea before. While Ciena says it currently doesn’t support the ability to allocate different wavelengths within the same pipe to different customers, it says that the application is on its roadmap for the future and, like Tellium's, will only require a software upgrade to its management suite.

As optical transport becomes a commodity, it’s important for carriers to take advantage of the intelligence built into their optical transport systems. And the optical switches providing this transport connectivity need to be able to facilitate these new value-added services. The intelligence in the switches that makes optical VPNs useful will soon become table-stakes for all optical switch makers, says Chris Nicoll, vice president at Current Analysis.

“Vendors in this market are looking for ways to add value to their existing products without requiring service providers to make big changes to their networks,” he says. “Carriers are starting to put more emphasis on a system's built-in intelligence rather than its speed and density."

While Tellium may have touched on an important concept with this new product announcement, it still must contend with the fact that its switch only offers wavelength grooming down to the OC48 level. While this may be adequate for carriers wholesaling capacity to other carriers, it may be overkill for service providers selling to individual corporate users.

“I don’t know what their customers are asking for, but if you look at our customer base, you have to assume they won’t all want OC48 pipes,” says Glenn Jasper, a spokesperson for Ciena, which has a product that grooms to the STS1 (51.8 Mbit/s) level. “They want something that grooms to a lower level.”

Tellium will demonstrate the StarNet Optical-VPN at Supercomm 2002, June 4-6, at the Georgia World Congress Center in Atlanta.

— Marguerite Reardon, Senior Editor, Light Reading
http://www.lightreading.com For more information on Supercomm 2002, please visit: Supercomm Special

Sign In