Paving the Way for ROADMs

Vendor Offers Enable Remotely-Reconfigurable Optical Networks

The mass move was predicted last fall when startup Photuris Networks Inc.’s V32000 was selected by Verizon Communications Inc., thus putting other vendors on notice.

Cisco Systems Inc., Lucent Technologies Inc. and Nortel Networks all announced ROADM technology at SUPERCOMM. Meriton Networks Inc. and Movaz Networks Inc. also have new offers in this space.

“The ROADM is one of the most important technological advances to hit the telecommunications market in the last decade,” says Bijan Khosravi, chairman and CEO, Movaz Networks, in a press statement announcing the June 2004 availability of its RAYROADM for metro and regional networks, “ROADMs simplify network operations by reducing the need for multiple transport layers. Fewer layers to manage will improve network reliability. Clickthrough provisioning for adding or dropping services is a significant improvement over doing it manually.”

ROADMs support remote dynamic network reconfiguration on a per-wavelength basis without the need for a truck roll. They are designed to eliminate optical-electronic regeneration for passthrough wavelengths typical of first-generation DWDM systems and restriction of fixed optical ADMs, such as wavelength stranding, perwavelength engineering and jumper cabling to interconnect filter packs, transponders and line interfaces.

Movaz Networks’ RAYROADM is shown here in a multiring and single-ring metro application.

RHK analysts estimate a total ROADM market — including line cards — of between $327 million and $559 million by 2007. They report different opportunities in the metro and long-haul markets, noting the metro core is dynamic, so high wavelength accessibility and integration with SONET/SDH are necessary, while long haul is performancesensitive, so managing insertion loss and add/drop flexibility are critical. “Reconfigurability will ultimately be a requirement for most [long-haul] overbuild opportunities,” the analysts note in a research brief from a March 2004 report on ROADMs.“Metro vendors should look for clear signs of demand from their clients. Subsystem vendors should focus on selling to system vendors in a good position at ROADM-friendly operators. Service providers and vendors should travel the road to the reconfigurable optical network together.”

Nortel’s entry into the ROADM space came as part of its Common Photonic Layer, a new DWDM optical transport platform for long-haul and regional networks. John Hawkins, marketing manager for optical networks at Nortel, explains the modular shelf system is configurable to perform different functions in the network from line amplification to DWDM mux/demuxing and it also can act as a ROADM.

“It simplifies engineering of lines using software called DOC, which gets involved in the early phase of planning link architecture,” Hawkins says, adding that it automates planning and provisioning, and monitors performance on an ongoing basis.

The system is shelf-based with no backplane. Modules, such as amplifiers and muxes, are linked by fiber. Ethernet provides the control link between DOC and the other modules.

“The flexibility really is a function of the ROADM,” says Hawkins, explaining that a wavelength can be dropped from any amplification site by adding a wavelength blocker shelf. The wavelength blocker makes the ROADM work by giving control over whether a wave is passed through or blocked. Hawkins says that sometime next year Nortel plans to add a wave selectable switch to allow a third option for directing waves as opposed to a simpler pass/no pass function. “It’s the full-blown notion of optical switching,” he says.

Cisco also announced at the show enhancements to its Cisco ONS 15454 Multiservice Transport Platform, including the addition of ROADM functionality, for metro networks. “ROADM is a big advancement that we are talking about at SUPERCOMM,” says Jim Sauer, director of product management for Cisco. Carriers can drop or pass through any of 32 channels using a software interface. “When they turn up service, the only hardware involved is at the ingress or egress,” he says. “It’s much more SONET-like.”

Sauer says Cisco engineers designed the ROADM to be cost-effective on the low end. “Others prove in at high channel counts, but very few networks get proved in at 32 channels,” he says, explaining a majority of networks are deployed with less than 16 channels. While declining to commit to an absolute threshold, Sauer indicated reconfigurability provided by the ONS 15454 MSTP can be less expensive than fixed filters at typical initial deployment levels.

“We believe we can prove in on the capex,” he says. “The other side is opex.” Sauer cites one customer study comparing manhours for the reconfigurable ONS 15454 MSTP and traditional fixed DWDM that shows about 40 percent savings on operational work hours with a 16-channel system and about 50 percent with a 32-channel system.

For its part, Lucent Technologies’ ROADM product is incorporated into its new Metropolis Wavelength Services Manager (WSM), a new metro and regional C/DWDM product that was jointly developed with Movaz Networks under an agreement announced in February. WSM is integrated into Lucent’s existing optical networking portfolio, including the Metropolis Enhanced Optical Networking, a 32-channel metro DWDM system. T-Com, the fixed-network division of Deutsche Telekom, will begin testing the system this summer.

Ken Wirth, president and general manager of Lucent’s Optical Networking Group, told xchange it also has incorporated its own Bell Labs’ ROADM capability into its LambdaXtreme Transport long-haul DWDM system, which now supports rings as well as spans. Wirth says some long-haul routes are approaching saturation and carriers will be looking for third-generation DWDM systems like LambdaXtreme to offer 10gbps to 40gbps capacity plus the ring architecture and ROADM capabilities. “Two to three years later (after adding new optics on individual routes), they will have built a new network,” he says.

Movaz Networks also unveiled its own ROADM product, RAYROADM, for metro and regional networks. It can be sold as a stand-alone device or added as a shelf to the RAYexpress OADM.

Uniquely, RAYROADM claims the ability to add Raman amplification technology to boost its reach to 1,000km. It supports 40 non-banded wavelengths. Early next year, a second release will support four rings each of 40 wavelengths for a total of 160 waves. The RAYROADM also uses a GMPLSbased control plane to ensure end-to-end control and management for simplified OAM&P and network management operation.

A key feature of the Movaz RAYROADM is that it allows remote, automatic, hitless reconfigurability of any wavelength or combination of up to 40 wavelengths. This is important to carriers and cable operators because it simplifies network operations by eliminating manual provisioning.

NETMARKS Inc. is set to begin trials in Japan, the companies announced.

Lucent’s Wavelength Service Manager includes ROADM functionality.

Meriton Networks, through a technology partnership with Capella Photonics, has incorporated reconfigurability in Release 2.0 of its 7200 OADX (Optical Add/Drop Switch). The Capella WavePath product provides functions, such as multiplexing, demultiplexing, switching, dynamic channel equalization, variable optical attenuation, power monitoring, tunable filtering and wavelength connectivity confirmation within a compact module. This is in contrast to wave blocker technologies common to ROADMs.

Rob Gaudet, director of product management for Meriton, says the cost of WDM components has come down, making regeneration less expensive, so the ROADM functionality now begins to make economic sense at 10gbps speeds. “[For users of Meriton’s 7200 OADX,] ROADM makes sense when there is lots of pass-through,” he says. Meriton’s electronic switching fabric always has had ROADM-like reconfigurability — making its view of the ROADMs fit in the network a bit different from the pack, he adds.

The optical ROADM interface cards for the Meriton 7200 OADX are set to be in trials with CLECs and IOCs by the end of this year.

Other companies announcing ROADM upgrades at SUPERCOMM included early market entrants Photuris and Fujitsu Network Communications Inc.

Fujitsu announced its FLASHWAVE 7500 extension system, which Senior Director of Marketing Communications John Stewart describes as a small, lowend version of the company’s FLASHWAVE 7500 ROADM system introduced last year. “It doesn’t make sense to have a full ROADM to extend/drop traffic,” he says.

Positioned for use in small and medium cities, the new FLASHWAVE 7500 extension system can be used to build point-to-point or ring networks of up to 16 wavelengths for core applications. As bandwidth demand grows, carriers can upgrade the system to a FLASHWAVE 7500 ROADM system. With the in-service addition of a single shelf, the platform becomes a key component in converged core networks, supporting 40 C-band wavelengths, auto-provisioning/auto-power balancing and a flexible optical switch core that allows any channel to be dropped at any node.

Photuris’ product, which was acquired by Mahi Networks Inc. in an acquisition finalized in mid-June, is now called the Vx7 Multiservice Core Transport System. Release 2.1, announced at SUPERCOMM, adds 100 percent ROADM capability to enable customers to add, drop or reconfigure one or all system wavelengths at any node around the ring remotely — with no service-affecting disruptions.

The Vx7 dynamically switches any 2.5gbps or 10gbps wavelength to or from any node. Wavelengths are managed individually and can be reused within a network. The Vx7 system software automatically discovers new equipment, updating the network configuration without manual intervention while the automated optical layer dynamically adjusts and balances power levels of each wavelength as services are added or removed.

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