Lucent Technologies Inc.

Wilhelm Kremer

James E Ballintine

Mark A Bordogna

Kamal Kumar Raychaudhuri

Bruce Lee Nelson

A node for use in a multi-source ring transmission system includes a controller and storage. Identifiers, such as ring addresses, for the relative first and relative last source nodes within the ring transmissions system are stored within the node's storage, in a squelch table for example. The node's relative first source node is the source node farthest upstream from the node and the node's relative last source node is the node that is farthest downstream from the node. The node blocks communications whenever both its relative first source node and its relative last source node fail.

Survivable distribution of broadcast signals in loopback rings

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.

Growing community of inventors

Dover, MA, United States of America

Wilhelm Kremer