ACTS to fly photonic research on PELICAN wings

By STEPHEN HARDY

The European Commission`s Advanced Communications Technologies & Services (ACTS) program has launched a project that will demonstrate a managed photonic network that includes both transport and access components. The Pan-European Lightwave Core and Access Network (pelican) effort, which ties together work from previous programs, will culminate in a field trial expected to begin in October 1999.

Three earlier ACTS programs form the basis of the pelican effort. The first of these is the Optical Pan-European Network (OPEN) project. As reported previously (see Lightwave, September 1998, page 101), OPEN investigated all-optical transmission across a long-distance network, including the use of wavelength-translating optical crossconnects that incorporated clamped-gain semiconductor optical amplifiers. Much of this technology came from the ACTS Keys to Optical Packet Switching (keops) program. The OPEN project concluded with a pair of field trials, one linking Norway and Denmark, the other running from France to Belgium.

The second project, Photonic Local Access Network (planet), recently completed field trials in Belgium of a passive optical network (PON) with a fiber-to-the-building configuration. The project aimed to demonstrate a PON infrastructure that would support a large splitting factor (up to 2000) and cover a relatively long distance (up to 100 km). The network used in the field trial consisted of singlemode fiber running from a local exchange to three buildings in the Belgian town of Woluwe-Saint-Lambert. The buildings are about 3.8 km from the exchange. A local distribution center between the exchange and the buildings housed the optical splitters. An Asynchronous Transfer Mode (ATM) switch from Alcatel was used as part of the infrastructure. Two feeder networks were used, one within Woluwe and another from outside the town. The network demonstrated the delivery of both narrowband/wideband and distributive/ interactive services.

The Management of Photonic Systems and Networks (mephisto) effort represents the third and final major supporting project. The mephisto program, which is ongoing, applies Telecommunications Management Network (TMN) principles to the management of optical networks and network elements. Project participants will combine the management requirements of the optical layer with a network-level specification approach to develop a simple, low-cost, generic approach to optical network management. Two testbeds are being used. The first consists of an emulation software platform for wavelength-division multiplexing (WDM) networks capable of emulating different network topologies and elements, particularly optical crossconnects. The second testbed comprises a rack-mounted WDM ring network prototype that contains optical amplifiers and reconfigurable optical add/drop multiplexers.

The task of the nine organizations involved in pelican is to tie these disparate pieces into a single network. The parties involved in the project include Alcatel CIT--Corporate Research Center (the project leader), France Telecom--CNET, and SEMA Group Telecom, all of France; Alcatel Bell--Corporate Research Center and Belgacom SA of Belgium; Germany`s Alcatel SEL AG--Corporate Research Center; Royal PTT Nederland NV, KPN Research of the Netherlands; and the National Technical University of Athens in Greece.

The project participants have split pelican into three "work packages." The first, now underway, consists of field-trial definitions, feasibility assessments, laboratory work, and evaluation of the field trial. The second package covers the work necessary to adapt the OPEN and planet hardware to the specifications developed in the first work package. Specifically, the PON hardware from planet will benefit from the addition of a media access control protocol for upstream transmission. The protocol should improve the network`s statistical multiplexing capabilities and lead to more efficient sharing of the network`s available bandwidth.

Meanwhile, the switching capacity of the optical crossconnects from the OPEN project will be increased as part of this second work package, as will the maximum bit rate (to 10 Gbits/sec). Versions of the crossconnect without wavelength conversion also will be part of the field trials. New optical nodes also will be fielded. Network elements, including optical amplifiers, will integrate the hardware required for operations administration and maintenance and network management in accordance with the mephisto project.

The third work package centers on network management. Within the access network, control messages will be transmitted via an ATM VP/VC channel carried by the network itself, thus eliminating the need for a separate data-communications network. For management of the transport network, TMN-compatible performance-monitoring facilities will be added to the system previously developed for the optical nodes. mephisto applications also will be included.

Three architectures

The field trial network at the heart of these work packages will comprise three different architectures derived from the OPEN and planet projects (see Figure). A meshed transport network from OPEN will link Paris, Amiens, Reims, and Lille. Wavelength-routing optical crossconnects will operate in Paris and Lille, while the optical crossconnects in Amiens and Reims will perform wavelength translation. Traffic will flow within this mesh at both 2.5 and 10 Gbits/sec.

In Lille, this mesh network will connect with a metropolitan area ring network joining Lille with Tournai and Brussels/Stro, using wavelength-translating add/drop multiplexers developed for the mephisto testbed. Each section of the ring will support four channels at 2.5 Gbits/sec.

Traffic from the Brussels multiplexer will pass through a line-terminating equipment unit to an access node that marks the beginning of the access PON. An optical repeater unit will split the network in three, with branches running to Woluwe and to European Commission facilities within the Belgian Parliament and Beaulieu. The network will support bidirectional transmission. Downstream traffic will be transmitted using time-division multiplexing in the 1550-nm window at a rate of 2.5 Gbits/sec. Upstream, traffic will run via time-division multiple access at 311 Mbits/sec using the 1300-nm window.

The field trial is expected to run through the first quarter of 2000. At its conclusion, the participants hope to have demonstrated not only a variety of architectures and optical elements, but also methods of managing them successfully. o