Alphion Corporation

Lucent Technologies Inc.

Frank N Hujber

Bharat P Dave

Yufei Wang

Boris Stefanov

Paramasiviah Harshavardhana

Tan Buu Thai

Ronald Simprini

Mohammad Laham

Roman Antosik

Jiten Sarathy

Oded Hauser

Chinnabbu Ekambaram

Ravi Vora

Raj Acharya

Jayantha Das

Randolph Roy Kutz

Khem Gandhi

David Lowe

Cathy Zima

Frederick Renner

Cathy Helen Zima

A method and apparatus are disclosed for monitoring and signaling a path restoration using pre-computed restoration paths following a detected fault on a primary service path in a communications network. A fault occurring inside the restorable portion of a network in heterogeneous or multiple network environments can be distinguished from faults occurring outside the restorable network in accordance with the ANSI Tandem Connection Maintenance standard, T1.105.05-1994. Path restoration is activated only when a fault causing path failure occurs inside the restorable portion of the network. Each conforming node in the restorable portion of the network has the necessary monitoring, signaling and cross-connect functionality and databases to participate actively in real time restoration. Additional non-conforming network elements can be positioned between the restoration nodes without preventing path restoration. With the signaling architecture of the present invention, when an end-node detects a path failure caused by an in-network fault, it formulates a signaling message for restoring the failed path. The restoration signaling message is thereafter relayed from one node to another in the overhead or payload of signaling paths that occupy the same bandwidth that is subsequently used by the restoration path. Once a signaling message is transmitted to an adjacent node in the overhead or payload of a particular signaling path, the node that transmitted the message makes a cross-connect that replaces the signaling path with a segment of the restoration path whose set-up was requested in the transmitted signaling message.

Method and apparatus for signaling path restoration information in a mesh network

In a novel restoration management method and system, the restoration messages are treated in two ways simultaneously so as to avoid delay in transmitting to a next node. In particular, a router alert bit is attached to each restoration message at an edge of the restoration network, which is read by a Label Switched Router so as to identify the restoration message as such. Then the restoration message is duplicated. The original one is directly forwarded to the next node through the shim player so as to avoid any delay. The duplicated one is sent to the application layer at the node for being processed there.

Restoration management system and method in a MPLS network

The present invention provides an optical signal quality selection system for optimizing the quality of information transmission. The system splits an incoming optical signal into two equal signals. The split signals are evaluated in optical performance monitors, transmitting an electrical output message to a signal selector relating to the quality of the respective signal. A second electrical message is sent from the optical performance generator to an alarm indicator signal generator, which sends an optical signal to the signal selector to drop the one of the split signals and transmit the non-dropped split signal. An unequipped optical signal from an optical idle signal generator is triggered if no active optical signal is being transmitted.

Optical signal quality selection system

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Mercerville, NJ, United States of America

Frank N Hujber