Abstract: A method of path protection for a connection-oriented packet switched communications network is described using a protection hub in communication with a worker hub via a core protection path. Both the worker hub and the protection hub communicate with at least one provider edge device via a respective worker and protection paths. The method detects a failure in the communications network, indicates the failure to the at least one of the provider edge device, the worker hub, and the protection hub. The method then employs the core protection path if a failure occurs along a worker path is detected, or a worker path and a protection path in parallel if a failure occurs along the core protection path.

Abstract: Method of re-routing traffic in a communications network (1) in the event of a fault (3) on a path across the network, the method comprising, determining whether a first node (4), located between the fault and a network ingress node (6), is capable of switching traffic to an alternative path which avoids the fault, and if the first node is determined to be not so capable, then determining whether a second node (8), located upstream of the first node, is capable of switching traffic to an alternative path which avoids the fault.

Abstract: A telecommunication network comprising a plurality of nodes including a content source (2) and at least one content receiver (3), the content source and the or each content receiver being connected via at least one switch node (4, 5, 6), and wherein the content source (2) is adapted to provide content that is associated with a multicast address to the at least one content receiver (3) using multicast communication. The network further comprises a content bandwidth indication generator node (3, 6, 7), the generator node being adapted to include an indication of the bandwidth requirement of the content supplied by the content source (2) along with the corresponding multicast address within a multicast protocol message (20, 60). At least one of the switch nodes (4, 5, 6) is adapted to extract said indication from the multicast protocol message and control the flow of content in response to said indication of the bandwidth requirement.

Abstract: Network interconnection apparatus comprising a platform with interface ports for network interconnection and comprising in turn a first series and a second series of interface port cards and an interconnection unit for commanded interconnection at least between the cards of the first and second series and between cards of the first series. The cards of the first series have their own associated MAC address tables for addressing traffic between ports through the interconnection unit. Each entry of the table has an age field defining in time the age of the entry. The content of the age field is periodically verified and if it reaches a preset maximum figure the entry is updated on the basis of the content of the age field by a corresponding entry in the table of another card of the first series and associated therewith by the information in the entry to be updated. If the content of the age field of the corresponding entry is also a maximum figure, both the entries can be deleted.

Abstract: An apparatus and a method are described in which a flow of packets is distributed in several separate flows over several links (12) forming a logically aggregated link (11). The flow outgoing from each physical link is sent to its own policer (18) which applies to said flow a traffic policing algorithm with the policers being interconnected to exchange algorithm control parameter modification information to fit them in among the various policers while allowing for the control parameters of the others so that a distributed policer (15) is realized.

Abstract: A method of, and apparatus for, determining multiple spanning trees over a computer network, each spanning tree providing a particular arrangement of communication links between nodes of the computer network, and the method comprising increasing a cost associated with using a particular communications link if said communications link is included in a previously determined spanning tree.

Abstract: Network interconnection apparatus (10) comprising a platform with interface ports (12, 14) for network interconnection and comprising in turn a first series (11) and a second series (13) of interface port cards and an interconnection unit (15) for commanded interconnection at least between the cards of the first and second series and between cards of the first series. The cards (11) of the first series have their own associated MAC address tables (16) for addressing traffic between ports through the interconnection unit. Each entry of the table has an age field defining in time the age of the entry. The content of the age field is periodically verified and if it reaches a preset maximum figure the entry is updated on the basis of the content of the age field by a corresponding entry in the table of another card of the first series and associated therewith by the information in the entry to be updated.

Abstract: A method of deriving an indicator of the signal quality in an in-service packet-based network at least having means to detect errors in packets and means to determine the overall amount of network traffic received. The method comprises the steps of: obtaining a value of the number of packets received having errors therein; obtaining a value of the overall amount of the network traffic received; calculating the indicator of signal quality (eBER) using the ratio of the number of packets received having errors therein to the overall amount of network traffic received.

Abstract: A connection oriented communications network 10 comprises a plurality of nodes including a plurality of edge nodes 12, 14, 16, 18. The network is arranged to define a primary tunnel connecting a primary one 12, 14 of the edge nodes to another edge node 14, 12 and a secondary tunnel connecting a secondary one 16, 18 of the edge nodes to another edge node 12, 14, 16, 18. The network is arranged to enable switching of traffic from the primary tunnel to the secondary tunnel in the event of detection of a failure in the primary tunnel.

Abstract: A protection scheme for a metro optical network involves programming ingress nodes and egress nodes with a primary multicast label switched path (LSP) and a back-up LSP to provide one-to-one protection. The primary and back-up LSPs are configured prior to the occurrence of a network fault to allow the network to transmit multicast communication when the fault occurs. Particularly, multicast communications are sent on the primary LSP during normal operation. However, when a network fault occurs, the nodes also send a duplicate multicast communication over the back-up LSP. Configuring the primary and back-up LSPs prior to the fault occurring avoids the need for signalling to establish a working LSP after a fault occurs.

Abstract: A method of path protection for a connection-oriented packet switched communications network is described using a protection hub in communication with a worker hub via a core protection path. Both the worker hub and the protection hub communicate with at least one provider edge device via a respective worker and protection paths. The method detects a failure in the communications network, indicates the failure to the at least one of the provider edge device, the worker hub, and the protection hub. The method then employs the core protection path if a failure occurs along a worker path is detected, or a worker path and a protection path in parallel if a failure occurs along the core protection path.

Abstract: An apparatus and a method are described in which a flow of packets is distributed in several separate flows over several links (12) forming a logically aggregated link (11). The flow outgoing from each physical link is sent to its own policer (18) which applies to said flow a traffic policing algorithm with the policers being interconnected to exchange algorithm control parameter modification information to fit them in among the various policers while allowing for the control parameters of the others so that a distributed policer (15) is realized.

Abstract: A method and a transport scheme for packets of traffic over a logical link made up of the aggregation of several physical links (16) connecting a transmitting side to a receiving side in which flows of incoming packets are sent to a scheduler/shaper (12) which selects therefrom packets for creating a global flow of packets falling within the bandwidth offered by the logical link on the basis of the bandwidth capability offered by the logical link. A distributor (13) distributes the global flow over the plurality of physical links (16) making up the logical link, oversees the physical links and sends to the scheduler/shaper signalling of a bandwidth decrease caused by failures of one or more physical links. The scheduler/shaper (12) is arranged to allow automatically for the logical link bandwidth variations while selecting the packets from the various incoming queues depending on the associated service class so as to cause the global flow to fall within the aggregated logical link bandwidth.