Abstract: A data communication apparatus having a plurality of working ports for exchanging data traffic with a network element and at least one protection port. The communication apparatus also has a protection switching functional element to switch data traffic from a failed working port to the at least one protection port. The protection switching functional element is capable to acquire either one of a first mode of operation and a second mode of operation. The first mode of operation is an 1:Q mode using a single protection port where Q is the number of working ports and Q is equal or greater than 1. The second mode of operation is an M:N mode where M is the number of protection ports and N is the number of working ports, where M and N are greater than 1.

Abstract: It is proposed that currently unused portions of transport overhead in frames sent on a high-speed outgoing channel be used to carry error count information from each of four low-speed input channels. At a 4:1 combiner, error monitoring bytes are extracted from transport overhead of frames received on each of the four input channels. Error counts are determined and accumulated for each input channel before being passed to a transport overhead generator for the outgoing channel, where they are inserted as bit patterns in unused portions of the transport overhead. At a receiving demultiplexer, the error counts are extracted from the transport overhead of incoming frames. The extracted error counts are then used to alter the error monitoring bytes included in the transport overhead of frames sent on each of four outgoing channels such that, at the far end of those outgoing channels, a correct number of errors for the three part path may be determined.

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: The present invention relates to a local node for use in a synchronous optical network ring. The local node includes a group of working transmission lines and a protection line, for connecting to a remote node. The local node further includes a control unit for monitoring the working transmission lines and, upon detection of a data transmission impairment over a particular working transmission line, invoking a protection switch event causing re-routing of optical signals from the particular working transmission line to the protection line. Should the control unit detect simultaneous data transmission impairments over two or more working transmission lines, the control unit will choose to protect a particular working transmission line on the basis of a user-defined priority scheme.

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: It is proposed that currently unused portions of transport overhead in frames sent on a high-speed outgoing channel be used to carry error count information from each of four low-speed input channels. At a 4:1 combiner, error monitoring bytes are extracted from transport overhead of frames received on each of the four input channels. Error counts are determined and accumulated for each input channel before being passed to a transport overhead generator for the outgoing channel, where they are inserted as bit patterns in unused portions of the transport overhead. At a receiving demultiplexer, the error counts are extracted from the transport overhead of incoming frames. The extracted error counts are then used to alter the error monitoring bytes included in the transport overhead of frames sent on each of four outgoing channels such that, at the far end of those outgoing channels, a correct number of errors for the three part path may be determined.

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: 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.