A telecommunications switching system employing multi-protocol routing optimization which utilizes predetermined and measured parameters in accordance with a set of user priorities in determining the selection of a telecommunications path to be utilized for transmitting a data file to a remote destination. The switching system has a first memory for storing the data file to be transferred, a second memory for storing predetermined parameters such as cost data associated with each of the telecommunications paths, a third memory for storing a set of user priorities regarding the transmission of data files, and means for measuring the value of variable parameters such as file transfer speed associated with each of the telecommunications paths. Processor means are operatively associated with the second and third memories and the variable parameter measuring means for determining which of the plurality of telecommunications paths should be utilized for transferring the data file in accordance with the set of user priorities, the predetermined telecommunications path parameters, and the measured variable parameters. The switching system further comprises input means for allowing a user to change the user priorities in the third memory prior to transmitting a file.

Multi-protocol telecommunications routing optimization

A method and apparatus is provided for automatic protection switching in a ring network by creating a protection domain having a control vlan and protected data vlans and designating a master node and transit nodes connected by a primary port and a secondary port. The master node blocks the secondary port for data vlan traffic until it detects a fault either by notice from a transit node or by polling. When a fault is detected, the master node unblocks the secondary port for data vlan traffic. When the fault is restored, the transit node temporarily blocks the restored port to data vlan traffic thereby preventing a loop. Each time the secondary port is blocked and unblocked, the forwarding databases on all the nodes are flushed.

Ethernet automatic protection switching

In a ring topology network, a number of nodes interconnect transmission links to form first and second working rings and first and second optical protection rings in a ring topology. Multiple working paths are established on each working ring and multiple protection paths are established on each protection ring corresponding to the working paths. A first working path spans across first and second nodes for transmission of a signal in a first direction of the ring topology, and a second working path of the second working ring spans across the first and second nodes for transmission of a signal in a second direction of the ring topology opposite to the first direction. A first protection path on the first protection ring spans across the first and second nodes for transmission of a signal in the second direction of the ring topology, and a second protection path of the second protection ring spans across the first and second nodes for transmission of a signal in the first direction of the ring topology. The first and second nodes normally use the first and second working paths, respectively. Responsive to a failure of one of the first and second working paths, the first and second nodes use a corresponding one of the first and second protection paths, instead of the failed working path.

Ring network for sharing protection resource by working communication paths

A cross-connect (92) for a multi-ring, multi-channel telecommunications network, especially for a wavelength-division multiplexed (WDM) optical network. Each of the interconnected rings (94 and (100) is self-healing by provision of a redundant counter-rotating ring (96 and 98)) or excess capacity on pairs of counter-rotating rings. Because an interconnect between self-healing rings (90) does not need to connect working to protection fibers, or similarly redundant fibers, the complexity of the interconnect can be substantially reduced. For several important architectures, the interconnect can be decomposed into one or two 3x3 interconnects. Further, a wide-sense non-blocking 3x3 interconnect can be advantageously implemented as four 2x2 switches, which may be a basic building block of optical switches. A novel algorithm is available to add new paths through such a 3x3 interconnect. The interconnect can be decomposed into one or two 4x4 interconnects when another pair of add (102)/drop (104) lines are added. Such an architecture provides full connectivity between user nodes connected to the add (102)/drop (104) lines and user nodes attached to the rings.

Inter-ring cross-connect for survivable multi-wavelength optical communication networks

A bidirectional logical-ring network employs crossconnect nodes, which partition the network into segments and interconnect segments at the subchannel level to form logical ring structures. All segments are independent, and each segment includes a subset of Add-Drop Multiplex nodes (ADMs) and two pairs of links, one working and one protection. The formation of logical rings from the interconnection of independent segment subchannels preserves the self-healing advantages of conventional bidirectional ring networks and allows greater flexibility to effeciently accommodate bandwidth upgrade requests.

Self-healing bidirectional logical-ring network using crossconnects

A transmission system comprises nodes coupled in a ring via two multiplexed transmission paths having opposite transmission directions. The two paths can be time, space, or wavelength division multiplexed. Bidirectional communications between any two nodes are provided in normal operation using both paths around a first, most direct, part of the ring. In the event of a fault affecting such communications, a protection switch is made to maintain bidirectional communications between the two nodes using both paths around a second, remaining, part of the ring. In this manner, each path can simultaneously carry both normal and protection switched signals. In an embodiment of the invention, only the two nodes adjacent a fault need be aware of the fault, each of these nodes effecting a protection switch for signals terminated at the node and effecting a protective loopback for other signals needing protection. The invention enhances the total capacity of the paths for carrying normal and protection switched signals. A network may comprise a plurality of such ring transmission systems intersecting at at least one network node, the network node comprising a node of each ring and a cross connect switch for switching signals therebetween.

Ring transmission system

A discontinuous ring is formed by separate bidirectional optical communication links, with possibly different transmission speeds, synchronous or asynchronous transmission, and ratios of working to protection channels, each linking a pair of terminals in different nodes of a communication system. To protect protection-switched traffic on a communication link from a link failure, it is routed around the ring via the protection channel of the other communication links. To this end, an optical switch is provided between the protection channel of each link and the associated terminals in each node, and is controlled differently in nodes adjacent the link failure and in nodes not adjacent the link failure to route the protection-switched traffic accordingly. Rapid protection switching is facilitated by controlling the optical switches using wavelength detectors directionally coupled to the protection channel at each node.

Optical communication system

An optical communications network configured in a shared protect capacity architecture. The network includes a plurality of shared and unshared nodes; a plurality of working lines connecting the plurality of nodes to form a ring that shares two or more nodes with another ring; a shared protect fiber optic line connecting the two shared nodes; and a plurality of protect lines connecting the plurality of unshared nodes which are connected by the plurality of working lines. By optically coupling a first Add-Drop Multiplexer of a first shared node to a first port of an optical cross connect using a first connecting path; optically coupling a second Add-Drop Multiplexer of the first shared node to a second port of the optical cross connect using a second connecting path; and optically coupling a third port of the Optical Cross Connect to a second shared node through a shared protect path, both rings may use the shared protect path to re-route traffic therethrough in the event that one of the rings has a break which severs the working and protect lines which couple two of the nodes thereof. The reduction in the quantity of protect lines, hence the fiber, and the equipment resulting in the associated cost savings are transparent to bit or baud rate, type of optical fiber, and signal format.

Telecommunications network having shared protect capacity architecture

A communication network for transmitting and restoring an optical signal in a data optimized optical ring is presented. The optical ring includes nodes, each containing an optical cross connect switching fabric that is coupled to a data switch. The optical cross connect switching fabric and the data switch may further be coupled to a short reach side of at least one wavelength translation device and a long reach side of the wavelength translation device is coupled to a dense wave division multiplex coupler. Each node includes at least one protect channel and at least one working channel for transporting the optical signal. The data optimized optical ring is adapted to carry extra optical signals, which are unprotected and un-restored low priority signals. By concurrently transporting and processing the extra optical signals and the regular optical signals, the network's capacity is increased resulting in greater traffic utilization.

Thomas P. J. Flanagan

Papers

Ring transmission system

Optical communication system

Telecommunications network having shared protect capacity architecture

Communication network for transmitting and restoring an optical signal