Optical switches are perhaps the most important new network element introduced into the telecommunications network since the EDFA. Though at first glance little more than a large circuit switch at the network core, they are in fact the key to unlocking the power of DWDM networks.Today, high capacity DWDM networks do little more than provide the “plumbing” for services to travel through. They are designed to be “dumb” and entirely agnostic to the types of services being carried within. That worked well enough while the network grew at a manageable pace and services were in the megabits, but once the Internet took hold and carriers were forced to scale their backbones rapidly, managing all the bandwidth terminating at core network nodes became a massive headache.
In addition, carriers began selling bandwidth in “optical” chunks, OC3s, 12s, and 48s. The only way to provision that kind of capacity quickly from a backbone is via a switched architecture. Without switches, every connection has to be “nailed up,” a process that can take weeks or months, which is unbearably long in the Internet era.
The optical switching market is maturing in 2001, with many of the proposed systems and architectures beginning to take shape.
Today, switches can be classified as OEO (optical-electrical-optical) grooming switches, OEO optical crossconnects, photonic transport switches (often called wavelength-selective crossconnects), and photonic crossconnects.
All these switches share the common function of moving large amounts of capacity from one fiber route to the next in a large distributed optical network. They differ in how they accomplish the task and at what granularity.
Today, the grooming switches have the most traction with carriers because they extend the function of their existing digital crossconnect systems, which top out at OC3 (155 Mbit/s) or OC12 (622 Mbit/s) switching granularity. Optical crossconnects and transport switches tend to be optimized around a core mesh architecture, which takes longer for a carrier to adopt.
Carrier Wish List
Outlook
This market is destined for greatness. Today, all large carriers agree that optical switches are necessary. There remains a strong debate over just how to implement optical switches, whether to migrate to a mesh backbone architecture, and when to adopt pure photonic systems, but all carriers agree on the need to improve the flexibility of their optical backbones.
It comes down to operations costs and provisioning times. To stay competitive, carriers need to vastly improve both of these, and optical switches are the clear solution.
Today the grooming switches are doing well with carriers because they are much easier to implement than purely photonic switches. These grooming switches will have a place in the core and the network edge, giving them a much longer useful life than their photonic competitors often argue.
Photonic switches address the need for bit-rate and protocol transparency and will be deployed to even further simplify the network backbone. Look for these in 2002, with broader deployment in 2003 and 2004.
Related articles in Light Reading
Optical Illusions
Optical Power Trip
Optical Switch Market Faces Slow Start
Optical Switching: The Next Generation Vendors
OEO Grooming Switches and Crossconnects
Brightlink Networks Inc.
Ciena Corp. (Nasdaq: CIEN)
Cisco Systems Inc. (Nasdaq: CSCO)
Nortel Networks Corp. (NYSE/Toronto: NT)
Sycamore Networks Inc. (Nasdaq: SCMR)
Tellabs Inc. (Nasdaq: TLAB; Frankfurt: BTLA)
Tellium Inc.
Photonic Transport Switches and Crossconnects
Alcatel SA (NYSE: ALA; Paris: CGEP:PA)
Calient Networks Inc. Cinta Corp.
Coree Networks Inc.
Corvis Corp. (Nasdaq: CORV)
Ilotron Ltd.
Inara Networks Inc.
Lucent Technologies Inc. (NYSE: LU)
Luxcore
Nayna Networks Inc.
Network Photonics Inc.
Nortel Networks Corp. (NYSE/Toronto: NT)
Siemens AG (Frankfurt: SIE)
Unique or Unannounced
edgeflow Inc.
Inara Networks Inc.
Movaz Networks
Princeton Optical Systems Inc.
Teraburst
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