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Monet Consortium sets stage for millennium with demos of long-distance and local-exchange optical networks
Business Wire - January 22, 1997 08:15
FINANCIAL LUCENT MONET LU NEW-JERSEY TELECOMMUNICATIONS COMPUTERS ELECTRONICS COMED V%BW P%BW
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HOLMDEL, N.J.--(BUSINESS WIRE)--Jan. 22, 1997--Looking toward the millennium, scientists of the Multiwavelength Optical Networking (MONET) consortium here have demonstrated two innovative networking testbeds aimed at proving the technical feasibility of next-century, ultra-high-capacity commercial and defense communications systems. Such systems will use multiple wavelengths, or colors, of light to transmit billions of bits of information per second through optical fibers with more reliability and flexibility than is possible with today's network. A team of scientists from Bell Labs, the research and development arm of Lucent Technologies, and AT&T Labs have demonstrated a 2,000- kilometer networking testbed with 2.5 billion bits per second of digitized information on each of eight channels of light -- each channel another lane on a 20-billion-bit-per-second information superhighway. The optical layer of the new testbed is format-and bit-rate independent, and the researchers now plan to test multiple formats. Scientists at Bellcore, a provider of telecommunications software, engineering, and consulting services, have demonstrated a multiwavelength self-healing ring network. The experimental network equipment on the self-healing ring provides customers with a means to safely deliver their traffic across a regional multiwavelength network, even in situations where part of the network is damaged. This is the first part of a local-exchange networking testbed in Red Bank, N.J., that will later include several types of multiwavelength switches and wavelength-routed stars, all designed to determine the best mix of equipment for local public networks. MONET research on another experimental testbed -- featuring a cross-connect-system for configuring networks by switching wavelengths from place to place -- is underway at Bell Labs here and is expected to be demonstrated early this year. All three testbeds are being used to develop and test critical multiwavelength optical technology and networking concepts. The MONET consortium also includes Bell Atlantic, BellSouth, Pacific Telesis, and Southwestern Bell Technology Resources Inc., in cooperation with the National Security Agency and the Naval Research Lab. MONET was established in December, 1994 and is funded in part by the Defense Advanced Research Projects Agency (DARPA). "The technologies demonstrated by the MONET long-distance and local-exchange testbeds will be the foundation of the next-generation Internet, where the demands for quality of service, bandwidth, configurability and scalability will far exceed the capability of today's network infrastructure," said Bert Hui, program manager of DARPA's Information Technology Office. "We envision that the Department of Defense will continue to rely heavily on the Internet for a lot of our day-to-day communication needs." "The Bell Labs-AT&T Labs networking testbed is designed and engineered to evaluate the long-distance performance of signals originating from the other MONET networking testbeds. This interworking of testbeds is a critical feature of proving-in the feasibility of this new technology for networks of national scale," said Rod Alferness, head of the Bell Labs Photonic Networks Research Department. "The long-distance networking demonstration proves that the multi-color highway can be extended over long distances with errorless performance. "The MONET vision is not simply very high-speed, multiwavelength optical transmission links," added Adel Saleh, head of the Broadband Access Research Department at AT&T Labs. "It's about reliable, flexible high-capacity networking on a national or global scale." "The greatest benefits of multiwavelength technology will be realized in local-exchange networks when it's possible to dynamically set up an optical path to meet a customer's service request, supporting whatever bit rate or signal format the customer wishes to transmit," said Joseph Berthold, executive director - network systems research, Bellcore. "It will be even more attractive if the path can be made survivable in the event of an optical fiber cut. Exciting technology is useless, though, unless it can be managed automatically. In the complex operating environment of local networks, the management systems must have open interfaces, be interoperable with existing systems, and be constructed in such a way that they are easily modified and enhanced. They must also be highly reliable. "The MONET local-exchange ring network prototype at Bellcore marks the first demonstration of the type of networking equipment that multiwavelength optical networking technology will make possible, and the management support systems that will be needed to meet the needs of the local-exchange network." Future MONET plans call for
-- interconnecting the three New Jersey testbeds in 1997
-- establishing an experimental multiwavelength network that will link facilities at Bell Atlantic, the National Security Agency, and the Naval Research Lab in the Washington, D.C. area in 1998
-- interconnecting the networks, via an AT&T long-distance all-optical link in 1999.
The MONET Consortium's objective is to define and demonstrate the best way to achieve national-scale high-capacity, high-performance, cost-effective, reliable, transparent multiwavelength optical networking -- integrating network architecture, advanced technology, network management , and business drivers.
MONET represents the vision of a transparent, reconfigurable optical networking layer capable of supporting all currently employed or proposed telecommunications standards, including Synchronous Optical Network (SONET) services ranging from OC-1, which carries 51.8 million bits of information per second, to OC-192, at 9.953 billion bits per seconds, and Asynchronous Transfer Mode (ATM) broadband, multimedia and high-speed networking services.
The optical network would support virtually any future telecommunications standard, enabling graceful growth. Its support of a large variety of format-independent, bit-rate-independent and protocol-independent service has the potential of offering increased flexibility and economic advantages in commercial networks, and also is of particular interest to the U.S. defense establishment.
MONET LONG-DISTANCE NETWORKING TESTBED
Additional Technical Information
The key transmission issues to be confronted in a national-scale optical network are chromatic dispersion, optical-amplifier gain flatness, and optical nonlinearity. Careful amplifier design and fiber choice mitigated the effects of all three on the performance of signals transmitted over the 2,000-kilometer length of the MONET long-distance networking testbed. The testbed, demonstrated at the Bell Labs Crawford Hill facility in Holmdel, N.J., by Bell Labs and AT&T Labs researchers, is composed of three segments: -- Roughly 25% of its length consists of conventional single-mode fiber with 17 ps/nm-km chromatic dispersion
-- 40%, of positive-dispersion Lucent Technologies TrueWave(TM) fiber with 1.5 - 4 ps/nm-km chromatic dispersion
-- 35%, of six lengths of TrueWave fiber with alternating signs of dispersion. This gives a total chromatic dispersion close to the dispersion limit for 2.5Gb/s and results in a system that is quite sensitive to any spectral degradation arising from optical nonlinearities. The system operates over the full 2,000 kilometers while remaining within the following performance guidelines: -- All eight channels are transmitted with less than one dB transmission penalty. -- All eight channels have signal-to-noise ratios in excess of 20 dB referred to a 0.1 nm bandwidth. -- Gain variations over the channels were held to less than 5 dB without intermediate trimming. A wavelength add-drop multiplexer component (WADM) was included in the testbed in the configuration used for bit-error-rate measurements to demonstrate that signals broadened by optical nonlinearities could still pass through the WADM filters without impairment. Channel detunings as large as 0.3 nm gave negligible penalties. The MONET amplifiers are erbium-doped fiber amplifiers designed in a mid-amplifier pumped configuration with a highly inverted counter-pumped first stage for low noise figures and a co-pumped second state that produces high output power. This architecture also offers the opportunity to add passive optics, such as dispersion compensation or gain equalization filters in the mid-amplifier region where the impact of excess losses on system performance is minimal. Maximizing performance for the various WDM channels causes nonuniform gain among the channels, so gain-equalization filters are used to compensate for the gain. A fiber grating filter, composed of two long-period fiber gratings, was used for each amplifier. In coming months, the researchers will incorporate dispersion compensation and additional WADM components, using both AWG routers and multilayer film devices. They will employ three strategies for dispersion compensation: dispersion-compensating fiber (DCF) after each 80-km span of the conventional-fiber segment; DCF with much less frequent compensation in the positive-dispersion TrueWave segment; and self-compensation in the alternating-dispersion TrueWave segment. They will evaluate the relative performance of the three strategies at both high powers and higher bit-rates, which will provide information that is crucial to the design of optimal future networks.
MONET LOCAL-EXCHANGE NETWORKING TEST Additional Technical Information
The MONET local-exchange networking testbed, designed at Bellcore's Navesink Research and Engineering Center, demonstrates -- for the first time -- a four-fiber, six-node, survivable WDM ring network.
This local exchange (LEC) network testbed was designed to carry out transport experiments with eight-wavelength SONET OC-48 signals and/or a mixed format of digital and FM-modulated analog services. The network equipment along the ring supports wavelength add/drop under the control of a flexible and robust Network Control and Management (NC&M) system.
The major benefit of this reconfigurable, survivable WDM ring network is to provide high transport capacity, at low cost, for LEC networks and at the same time, to meet rapid capacity growth required by new high-bandwidth video and data services for future telecommunications and Internet networks.
The demonstrated WDM ring network consists of six wavelength add/drop multiplexers (WADM). Among them, two nodes are fully managed by software systems developed by a Bellcore team. Multiwavelength signals are monitored and controlled by network element controllers. Configuration, connection setup, fault detection and performance monitoring are accomplished by a multitiered, Element Management Layer and Network Management Layer, management system. The remaining four nodes are passive and unmanaged with only transport interfaces and pre-adjusted channel power equalizers. An automatic protection switching (APS) feature has been demonstrated.
Also demonstrated, for the first time, is stable interoperation of two eight-wavelength channel power equalizers using real-time feedback circuits between two separated WADM network elements in both attenuation and power control modes.
To communicate among network elements and the various components of the network management system, the team has constructed and tested a data communication network (DCN) for the local-exchange network testbed using an ATM overlay network and an OC-3c (155 Mb/s) signaling channel at 1310 nm wavelength.
Connection setup was demonstrated by using a four-channel, FM-modulated CATV video signal.
This is the first demonstration of a survivable, transparent multiwavelength ring network with a sophisticated network management system. This testbed will be used in conjunction with the testbeds developed by other members of the MONET consortium to demonstrate national-scale optical networking.
Further information about MONET is available on the Internet at: bell-labs.com .
CONTACT: Lucent Technologies - Bell Labs
Donna Cunningham, 802-482-3748
donnac@lucent.com
or
AT&T Labs
Brian Monahan, 908-582-4442
bmonahan@attmail.com
or
BellSouth
John Goldman, 205-977-5007
john.t.goldman@bridge.bst.bls.com
or
Southwestern Bell Technology Resources Inc.
Paul McLaughlin, 512-372-5958
pmclaugh@sbctri.sbc.com
or
Bellcore
Ken Branson, 201-829-2165
ludd@cc.bellcore.com
or
Bell Atlantic
Cindy Anderson, 703-816-4286
canderso@bell-atlantic.com
or
Pacific Telesis
Scott Smith, 415-394-3624
sesmith@legal.pactel.com
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