Abstract: In a mesh network, a network element for providing protection switching in a 1:N shared mesh protection scheme having a first protection path associated with a pair of working paths selected from the N working paths is disclosed.

Abstract: Protection techniques within optical communication networks are extremely important. An alternative to a line protection scheme, as most current optical communication networks use, is to utilize a path protection technique in which working and protection paths that are desired are assigned during network setup. During normal operations, only the working path is configured within the network elements' switch fabric with protection paths being left unconfigured. If a failure indication is detected in the working path by a network element, a protection entry within a routing table of the network element is looked up to determine protection switching data that is required to switch the data traffic to the pre-assigned protection path. This protection switching data is inserted within the path overhead for the data traffic so that it can be communicated to all of the network elements that require their switch fabrics reconfigured to establish the protection path of communications.

Abstract: In a mesh communications network, in which working and protection paths may be established, channels used to carry protection traffic between nodes are shared across multiple protection paths. Channels need only be shared if sharing does not adversely impact network usage. If working and protection paths become susceptible to single points of failure, channels need not be shared.

Abstract: Protection techniques within optical communication networks are extremely important. An alternative to a line protection scheme, as most current optical communication networks use, is to utilize a path protection technique in which working and protection paths that are desired are assigned during network setup. During normal operations, only the working path is configured within the network elements' switch fabric with protection paths being left unconfigured. If a failure indication is detected in the working path by a network element, a protection entry within a routing table of the network element is looked up to determine protection switching data that is required to switch the data traffic to the pre-assigned protection path. This protection switching data is inserted within the path overhead for the data traffic so that it can be communicated to all of the network elements that require their switch fabrics reconfigured to establish the protection path of communications.

Abstract: Methods, apparatuses, media and signals for providing clear channel access on a network are disclosed. A first method involves receiving a communication signal from a remote network element. The communication signal includes a previous transport overhead (PTOH) portion indicative of transport overhead contents of the communication signal prior to arrival at the remote network element, and a previous path error (PPE) portion indicative of path errors present in the communication signal at the remote network element. The method then involves modifying a transport overhead portion of the communication signal in response to the PTOH and PPE portions.

Abstract: A shared mesh protection scheme defines an associated protection path when a working connection is established. During the protection path definition, the corresponding protection path information is sent down to a switch card of network elements making up the protection path. Upon detection of the failure, the network elements using an overhead byte message will inform the routing source network element of the connection of the failure in the working path. The overhead bytes used are interrupt driven bytes located in the line and path overhead of network traffic. The routing source node of the connection will then send the corresponding overhead byte messages down the protection path to provide for protection path establishment according to the preloaded data located at the switch card. It should be noted that each connection can have a source and termination element which relates to the source from where the corresponding connection was set-up rather than the direction of the payload transmission.

Abstract: The working fibre and protection fibre between pairs of nodes are shared between adjacent rings in a network, such that working traffic on the working fibre between the pair of nodes can be protected by the ring architecture of either of adjacent rings. A network management system routes signals across the network and dictates which rings within the network provide protection for the signal route. The ring structure enables protection for signal traffic on a ring to be protected by the ring protocols, providing rapid protection switching. It is also possible to select the location of protection bandwidth for a signal path across the network. In this way, protection bandwidth is shares and can also be configured to optimise the use of the total available protection bandwidth.

Abstract: In a mesh communications network, in which working and protection paths may be established, channels used to carry protection traffic between nodes are shared across multiple protection paths. Channels need only be shared if sharing does not adversely impact network usage. If working and protection paths become susceptible to single points of failure, channels need not be shared.

Abstract: The present invention provides a method of deactivating working fibers in an existing optical ring network or system for a cost-effective and efficient allocation of the fiber resources available in the ring network. When a working fiber is underutilized in an existing ring network, the traffic scheduled for transmission thereon is re-routed around the network away from the fiber and lockouts are applied to prevent the fiber to be removed from being protected. The fiber and associated connecting equipment thus become unused and unnecessary for traffic carrying purposes and can then be deactivated. By eliminating the need for working fibers and associated optics equipment on spans where traffic is low or non-existent, the invention can provide fiber capacity savings of up to fifty percent on each span while retaining full protection usage.

Abstract: The present invention consists of a method of deactivating protection fiber resources in an existing optical interconnected ring network or system. The invention uses 1:N protection principles to provide a single protection path on spans interconnecting nodes common to two or more optical rings. With the sharing of a protection fiber or channel on spans interconnecting common nodes, the present invention eliminates the need for multiple protection paths on these spans and provides substantial fiber capacity savings. According to the invention, the protection fibers and equipment deactivated can be removed or alternatively re-provisioned to provide a cost-effective and efficient allocation of the resources available in the network.

Abstract: An important feature of communications networks is resilience in the event of failure. Conventional ring-configured networks use 100% bandwidth over provisioning so that in the event of failure of a fiber, a span which may be used to use the spare capacity on the same span and in the event of a total failure in a particular span of both working and protection capacity, it is possible to ring switch the data around the far side of the ring in order to provide total protection. However, 100% over provisioning of bandwidth in the network is expensive. By using up to half the protection bandwidth for working date and using span and ring switching together, it is possible to use some of the bandwidth capacity on the protection path and still retain a robust network configuration.

Abstract: A method of restoring data transport following a network resource failure in a communication network includes searching for protection bandwidth in a data transport ring where the transport resource failure occurred, and the search is extended to protection bandwidth on adjacent data transport rings, as required, until protection bandwidth for restoring data transport are located or all adjacent rings have been searched. Thus the ratio of working:protection bandwidth is improved by elimination of protection bandwidth between matched pair nodes interconnecting adjoining BLSRs of the network. However, high reliability which is characteristic of a BLSR network is preserved by providing a recovery algorithm that promptly allocates protection bandwidth of one or more rings, as required, in order to circumvent a failed network resource.

Abstract: A method and apparatus for redirecting data communications traffic in a mesh network via an alternate path. When operating in a SONET environment, the method makes use of bi-directional line switching ring (BLSR) principles in addition to a dynamically invoked flexible ring formation mechanism. The network comprises a plurality of computing nodes, where the plurality of computing node are interconnected to one another by a plurality of communication links and exchange traffic with one another over the communication links. The method includes detecting a failure on a certain communication link, the certain communication link interconnecting a first computing node and a second computing node. Upon detecting a failure on the certain communication link, at least one ring protection path is generated between the first computing node and the second computing node, where the ring protection path excludes the certain communication link.