Nortel Networks Corporation

Mark Acton Gibbon

Malcolm Betts

David Wright Martin

Sarto Barsetti

Xinyi Liu

Bogdan Jakobik

Andrew John Bryant

Paul A Bruce

Martin Agnew

The virtually unused switching fabric of an OC-192 SONET transport node is used to greater effect when used as a switching node. Several of the nodes are used in the central office (CO) of a communication network. Each node terminates an optical network link and each node hosts a number of transport cards that also terminate different optical network links. The nodes provide space-switching between the cards. Additionally an intra-CO optical link is provided that interconnects the nodes to allow traffic flow between any of the optical network links in the CO that are terminated by transport cards or the nodes.

Architectural arrangement for bandwidth management in large central offices

An optical amplifier arrangement comprises a splitter for providing an input WDM optical signal on at least first and second output paths. An optical amplifier is provided in at least one of the paths, and a signal routing arrangement is provided for routing individual channels or groups of channels of the WDM signal within the at least one of the paths. A switch selects the signal from one of the at least first and second output paths. In this arrangement, there are two paths between the input and output. Whilst one path is being used, the components in the other path can be upgraded. For example, a switching arrangement may be provided in the other path, and an amplifier may also be upgraded, without disrupting service in the path in use. This enables an amplifying node within an optical communications system to be incrementally upgraded.

Optical amplifier arrangement

A new architectural arrangement for network elements deployed in a central office (CO) is disclosed. The architectural arrangement involves dividing the network elements into an optical layer comprised of elements that have optical signal interfaces and switch optical signals, an opto-electrical layer comprised of elements that have optical signal interfaces and switch electrical signals, and an electrical layer comprised of elements that have electrical signal interfaces and switch electrical signals. The opto-electrical layer connects the optical and the electrical layer, and also connects lower-rate optical links into the CO. This layered architectural arrangement allows for more efficient use to be made of the small number of high-rate ports supported in the optical layer, and for the off loading of switching responsibility from both the optical and the electrical layers. This, in turn, improves the overall performance and capacity of the CO. The opto-electrical layer can be implemented using known transport nodes that are only slightly modified for deployment within the CO environment.

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London, United Kingdom

Mark Acton Gibbon