Tellabs Operations, Inc.

Cisco Technology, Inc.

International Business Machines Corporation

Nortel Networks Corporation

Rockstar Consortium US LP

Coriant Operations, Inc.

Ornan A Gerstel

Rajiv R Ramaswami

Stefano Piciaccia

Mauro Macchi

Philip J Lin

Gabriele Maria Galimberti

John C Carrick

Paul E Green, Jr

Robert R Ward

Mark I Oppenheimer

Loukas Paraschis

William Eric Hall

Valerio Viscardi

Mauro Rudi Casanova

Peter Lothberg

Ronald Johnson

Galen H Sasaki

Babu O Narayanan

Glen P Koste

Jean-Philippe Vasseur

Osama S Aboul-Magd

Chung-Sheng Li

John Duncan McNicol

Anand Girish Parthasarathy

Robert William Keys

Fabrizio Forghieri

Frederic J Simard

Giovanni Martinelli

Humair Raza

Gianpaolo Barozzi

Vasant Sahay

Chaoyu Yue

David Park

Mauro Rudy Casanova

Humayun Sohel

A wavelength division multiplexed optical communication system includes a plurality of optical line terminals which may be part of separate in service networks, each having a line interface and an all-optical pass-through interface including a plurality of pass-through optical ports, and each also including a plurality of local optical ports which are connectable to client equipment and an optical multiplexer/demultiplexer for multiplexing/demultiplexing optical wavelengths. The optical multiplexer/demultiplexer may include one or more stages for inputting/outputting individual wavelengths or bands of a predetermined number of wavelengths, or a combination of bands and individual wavelengths. At least one of the pass-through optical ports of an optical line terminal of one network may be connected to at least one of the pass-through optical ports of an optical line terminal of another network to form an optical path from the line interface of the optical line terminal of the one network to the line interface of the optical line terminal of the another network to form a merged network. The use of such optical line terminals allows the upgrading and merging of the separate networks while in service.

Optical line terminal arrangement, apparatus and methods

Automatic discovery and verification of optical communication links as well as isolation of link failures in an optical communication system.

Link discovery, verification, and failure isolation in an optical communication system

Switching architectures for WDM mesh and ring network nodes are presented. In mesh networks, the switching architectures have multiple levels&#x2014;a network level having wavelength routers for add, drop and pass-through functions, an intermediate level having device units which handle add and drop signals, and a local level having port units for receiving signals dropped from the network and transmitting signals to be added to the network. The intermediate level device units are selected and arranged for performance and cost considerations. The multilevel architecture also permits the design of reconfigurable optical add/drop multiplexers for ring network nodes, the easy expansion of ring networks into mesh networks, and the accommodation of protection mechanisms in ring networks.

Optical switching architectures for nodes in WDM mesh and ring networks

A method and system for setting a variable forward error correction overhead in an optical transport network frame for an optical link at a node are disclosed. In one embodiment, a method includes selecting a forward error correction overhead, signaling an optical node the selected forward error correction overhead, and setting the forward error correction overhead in the optical network transport frame for use in transmission of data over the optical link. In one embodiment, the forward error correction overhead is complementary to the data payload to maintain total transmission rate.

Variable forward error correction for optical communication links

In one embodiment, techniques provide a mechanism for tracking wavelengths in a DWDM network. In particular, embodiments of the present invention also provide for connection tracking using a slowly modulated pilot tone in a DWDM network without dedicated hardware for the generation and the diction of the tone.

Mechanism for tracking wavelengths in a DWDM network without specialized hardware

An optical control plane (OCP) distinct from an electronic control plane helps the setup of path routes in a DWDM network. The OCP determines the optical feasibility of any path route selected by the electronic control plane, such as operated under GMPLS protocol, and asks the electronic control plane for another path route if the optical feasibility is determined to be negative. The OCP can be set in a server or distributed across the nodes of the network.

Optical control plane determination of lightpaths in a DWDM network

The present invention provides a mechanism and a method for indirectly controlling a packet handling device interface from an optical management system in an packet-optical network. A mechanism is provided for controlling a packet handling device, such as a router, interface from a management system indirectly, by using optical equipment as a proxy and communicating between the optical gear and router via a peer-to-peer signaling protocol. The present invention provides a management method that allows separate management systems for the optical layer and the packet network layer and a method for managing the network across the domains.

Method for separation of packet network+optical management domains

Even though network connections have priorities for reconnection and preemption of other connections upon a failure, these priorities are fixed based on the Service Level Agreement (SLA) between the Service Provider and the customer, and do not depend on the actual outage time, or downtime, during the operation of the network. Only a fixed pecking order for reconnection is guaranteed. Therefore they cannot ensure the outage a connection which experiences downtimes limited to the SLA. With the present invention, the priorities of the network connections are determined responsive to the failures of the network connections. The priorities of the network connections can also be determined responsive to the permitted downtime of the connections to better meet the SLA of the connection. Another factor in varying a network connection priority can be the expected downtime of a connection.

Variable priority of network connections for preemptive protection

Optical performance measurements are taken in an optical network and displayed in a form that allows an operator to enter fault information related to the measurements, or to automatically generate fault alarms to the operator, based on processing of the measurements. The optical measurements may be individual power measurements taken for each light-path at various points in each node it traverses, such as amplifiers, multiplexers/demultiplexers or at an interface with another node.

Processing of optical performance data in an optical wavelength division multiplexed communication system

In one embodiment, first optical signal can be generated at a first end of an optical fiber segment at a first time. The first optical signal can be detected at a second end of the optical fiber segment at a second time. A second optical signal can be generated at a second end of the optical fiber segment at a third time in response to the detection of the first optical signal. The second optical signal can be detected at the first end of the optical fiber segment at a fourth time. A length of the optical fiber segment can be determined based on a difference between the second time and the first time, a difference between the third time and the second time, and a difference between the fourth time and the third time.

Measurement of optical fiber length and determination of chromatic dispersion over the optical fiber

The present invention provides a mechanism and a method for indirectly controlling a router interface from an optical management system in an IP-optical network. A mechanism is provided for controlling a router interface from a management system indirectly, by using optical equipment as a proxy and communicating between the optical gear and router via a peer-to-peer signaling protocol. The present invention provides a management method that allows separate management systems for the optical layer and the IP layer and a method for managing the network across the domains.

Method for separation of IP+optical management domains

Growing community of inventors

Los Altos, CA, United States of America

Ornan A Gerstel