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

A method of providing network services is described. The network includes a number of nodes, each one of which is coupled to at least one other of the nodes by at least one of a number of optical links. The network is preferably capable of supporting a number of virtual circuits. The method begins with the receiving of a request for a virtual circuit between a first node and a second node of the network. Preferably, the request specifies a quality of service of the virtual circuit. Next, the availability of network resources for supporting a virtual circuit at the requested quality of service is determined. Assuming sufficient network resources are available for support of the virtual circuit, the request is then serviced by provisioning (and maintaining) the requested virtual circuit. Servicing the request preferably includes actions such as provisioning, maintaining, and restoring the virtual circuit, using the requested parameters.

Method of providing network services

Setting of a bypass path upon occurrence of transmission failure, is applicable for large scale network. A system includes signaling means which makes judgment whether bypassing process is performed by an own node by a bypassing process judgement means when a release message issued upon occurrence of failure, is received. Upon judgment to perform bypassing process, computation of bypass path is requested by the path computing means. On the basis of result of computation, bypass path is established and switched. In the bypassing process judgment means, judgment is made whether bypassing process is performed by the signaling means or not depending upon the relationship of positions of the faulty portion and the own node.

Fault recovery system and transmission path autonomic switching system

With respect to a router in a backup path in an MPLS network adopting a label stack method, it is an object of the present invention to achieve the same quality-guarantee control as the one performed in a current path. In a packet transfer device accommodating first and second output lines, when the first line has a fault, upon a first packet being received, communication quality information in a header of the first packet is copied. Further, a first header containing the copied priority information and a new label is added to the first packet, and a packet to which the first packet is added is outputted to a second output line. When a second packet is received, communication quality information in a header of the second packet is copied, a second header containing the copied priority information and the new label is added to the second packet, and a packet to which the second packet is added is outputted to the second output line.

Method of transferring packets and router device therefor

A method of operating an network is described. The network includes a number of nodes connected by a number of links. A method according to the present invention provisions a virtual path between a first and a second one of the plurality of nodes by: identifying the first and the second nodes, discovering a physical path from the first node to the second node, and establishing the virtual path. The method discovers a physical path from the first node to the second node by automatically identifying nodes forming the physical path. The method establishes the virtual path by configuring a set of connections between the nodes forming the physical path.

Method of reducing traffic during path restoration

In an ATM virtual path switching node, upon being notified of a current virtual path by a virtual path monitoring unit, a link fault determination unit compares the number of faulty current virtual paths with a predetermined threshold value. When the number of faulty current virtual paths is equal to or larger than the threshold value, a link fault is determined, and a message communication unit transmits/receives a link fault notification signal to/from another ATM virtual path switching node. When the number of faulty current virtual paths is smaller than the threshold value, a current virtual path fault is determined, and the message communication unit transmits/receives a virtual path fault notification signal to/from another ATM virtual path switching node. The message communication unit transmits a switching control signal for designating switching from the current virtual path to a stand-by virtual path. A current virtual path information management unit manages correspondence between the current virtual path having, as one switching terminal, a self ATM virtual path switching node and a plurality of links in an ATM network.

Makoto Nishio

Papers

ATM virtual path switching node