Lucent Technologies Inc.

James E Ballintine

Paul Bonenfant

Wilhelm Kremer

Mark A Bordogna

Kamal Kumar Raychaudhuri

Bruce Lee Nelson

George W Newsome

A so-called digital &ldquo;wrapper&rdquo; is employed in conjunction with an optical channel client signal payload envelope to carry optical channel associated optical channel overhead. That is, the digital wrapper transports optical channel associated optical channel overhead and other monitoring information. This is realized by adding additional capacity, i.e., bandwidth, to the client signal payload envelope. The additional capacity is added &ldquo;around&rdquo; the payload envelope and the client signal floats in the payload envelope. This is effected in such a manner that the digital wrapper is independent of the type of client signal that is being transported on the optical channel. Indeed, as such the optical payload envelope is essentially a client optical signal independent, constant bit-rate channel. Moreover, in addition to the digital wrapper providing capacity for the optical channel overhead, it can also be employed to provide a forward error correction capability. Additionally, the added digital wrapper readily provides access for performance monitoring and, especially, access to electrical BER (bit error rate).

Apparatus and method for providing optical channel overhead in optical transport networks

Optical channel overhead information for individual optical channels is transported in a message based channel on an optical supervisory channel. Specifically, this is realized by obtaining performance monitoring, and/or performance measurement, and/or operations, and/or administration, and/or maintenance information, and/or the like for the individual ones of one or more optical channels, formatting the obtained information into a message for each individual optical channel and inserting the resulting message(s) into an optical supervisory channel to be transported on the OTN. In one embodiment of the invention, particular overhead information is formatted into a message and controllably inserted into the optical supervisory channel at a prescribed optical network element to be transported on the OTN. In another embodiment of the invention, particular overhead information is formatted into a message and controllably inserted into the optical supervisory channel at a prescribed optical network element to be transported on the OTN to a node including the capability to insert the overhead information into channel associated optical channel overhead to be transported to a network element at which it may be removed. Additionally, overhead information transported in channel associated optical channel overhead may be extracted, formatted into a message and inserted in a message based channel in the OSC. The OSC transports the optical channel overhead to a particular node not equipped for associated overhead insertion or removal, where it is extracted form the OSC and used as desired.

Methods and apparatus are disclosed for providing virtual rings in SONET networks. By using an unused byte in the SONET path overhead, in conjunction with multiframe operation, restoration is performed at the sub-network connection layer or path layer to provide a finer granularity of protection which provides more efficient use of bandwidth. By restoring the operation of the SONET path overhead before exiting a virtual ring created using the present invention, the present virtual ring can be applied to the existing SONET network. Since a virtual ring provides restoration at a path level, a virtual ring can be comprised of various SONET rate interfaces. Further, restoration circuits are not dedicated, but are shared to create virtual rings as needed, which increases bandwidth efficiency and which are automatically and quickly created without the need for a centralized controller.

Self-healing networks using virtual rings

A restoration procedure for use in bidirectional multiplex section-switched ring transmission systems re-establishes a connection path by using a loopback connection at nodes bordering the failure and by then establishing a jumpered connection path, for each active tributary affected by the failure. The jumpered connection path at affected node eliminates any unnecessary loop formed in the re-established connection path caused by the loopback connection at the border nodes. There is stored in memory at each node (1) the provisioned connection path, (2) the jumpered path, and (3) a jumper flag is set indicating that a jumper connection exists. When the failure is cleared the (1) jumpered path is removed and its record erase from memory, (2) the provisioned connection path is restored, and (3) the jumper flag is reset. Advantageously, the this operation can be programmed into existing node controllers and is compatible with existing restoration procedures.

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Colts Neck, NJ, United States of America

James E Ballintine