Optical Taxonomy

Optical Switching 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

  • A large matrix switch (more than 256 OC48s per system) in a pay-as-you-grow configuration
  • Grooming of STS-1 circuits in systems of 512 OC48 capacity or less
  • Switching of any bit rates or protocols in large matrix systems
  • Ease of implementation. Integration with existing core network systems.


    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)
    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.
    Next Page: Service-Aware Switches

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    Peter Heywood 12/4/2012 | 8:50:38 PM
    re: Optical Taxonomy We're planning on using the positioning matrix described in this report in other Light Reading articles where it would help to identify the target market of a company or a product.

    We think it'll aid more effective competitive analysis.

    I've experimented with the idea in the Wavesmith story, by adding a graphic. on http://www.lightreading.com/do....

    What you think?

    [email protected]
    Rugger 12/4/2012 | 8:50:36 PM
    re: Optical Taxonomy Where's Corvis in your listing of optical switch vendors??? Corvis is the only one delivering today. What's up with that?
    light_on_dude 12/4/2012 | 8:50:34 PM
    re: Optical Taxonomy WOW! This article/story just sucks. Was this written by a high school student working on a mid term paper? I usually defend lightreading on these boards, but damn...you guys really just don't know what you are talking about. This report reminds me of the cheesey analysts that come by my booth at a trade show..."what bucket do you fit in? ok thank you , buh bye...no info just qucik hit...I'm sad to say but the blokes who call you the "Optical rumor rag" are right
    arojas3 12/4/2012 | 8:50:33 PM
    re: Optical Taxonomy Did you forget to research Lucent until halfway through the report? We invented optical networking - show some respect.
    marcy281 12/4/2012 | 8:50:33 PM
    re: Optical Taxonomy I think you have to realize that the bulk of your readers already know an awful lot about telecom, networks, switches etc. I realize you have to reach a wide audience, but it's depressing to read something like this--a telecom for dummies thing.
    optinuts 12/4/2012 | 8:50:32 PM
    re: Optical Taxonomy peter, its a good idea if you know enough about the product and its feature set. however, on reading the taxonomy report, you made so many errors (eg missing both corvis and lucent from the photonics switch list and a whole list of vendors from the other categories) that you will be generating hate mail more than constructive commentary.

    you wrote a good report, you covered a lot of territory, but you should know there are limits to an idea.
    Heater 12/4/2012 | 8:50:32 PM
    re: Optical Taxonomy Granted, there are plenty of engineers who read Lightreading, but most of the folks who influence and/or control the purse strings are NOT engineers. Hence, if equipment vendors want to make sure their buyers are informed about what's going on in the optical market, they'd better be supportive of any efforts to educate those buyers.

    Moreover, I don't think anyone has really done a good job of organizing/cataloging the optical market. This document looks like a very good start in that direction. Nice job guys.
    Peter Heywood 12/4/2012 | 8:50:31 PM
    re: Optical Taxonomy Ok, OK...I had a feeling we'd missed some obvious names. Just let us know and we'll update things.
    pablo 12/4/2012 | 8:50:26 PM
    re: Optical Taxonomy I just got to say that Scott Clavenna is a great analyst, with a keen eye for the essentials of the business.

    This is an excellent piece.

    Thanks LightReading!
    Peter Heywood 12/4/2012 | 8:50:22 PM
    re: Optical Taxonomy Light Reading got a private note from someone questioning our adoption of Tenor's analysis of the market - saying that we'd fallen into the trap of seeing the world through Tenor's eyes.

    Just wanted to address this publicly:

    We adopted the functional framwork put forward by Tenor, but this really only reflects widely accepted dividing lines in the market - between transport and services and between access, metro and core. I can't see how this could skew our vision.

    When it came to selecting product catgories, positioning them in the functional framework and assembling lists of vendors, this was all our own work.

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