Corrigent Systems Ltd.

Orckit-corrigent Ltd.

Alex Levit

Ronen Solomon

Zvika Menahemi

Leon Bruckman

David Zelig

Gideon Agmon

Yossi Barsheshet

Muly Ilan

Ophir Fuchs

A method for handling communication failures in a network, which includes provisioning first and second multipoint-to-multipoint communication services over respective first and second alternative sets of links that connect the endpoints in a network. Each of the sets connects network nodes which provide physical layer resources for the links. The communication service is provided to the endpoints over the first set of links using the first service. Upon detecting a failure in the first set of links, the physical layer resources of the links in the first set are deactivated by the network nodes, in order to lose their connections. Responding the loss of connection, the communication service automatically transfers communication to the second set of links.

VPLS remote failure indication

Routing tables of OSI layer-3 network elements are modified in order to enable entry to a RPR subnet at different entry points. This enables virtual tunnels or routing paths to utilize all existing entry links to the RPR subnet and to minimize cost factors, such as the number of RPR spans required to traverse the RPR subnet from the entry point to a destination RPR node. The routing tables of RPR subnet elements are modified, such that traffic leaving different elements but destined for the same network location outside the RPR subnet may have individualized RPR exit nodes. The respective RPR exit points for the network elements are chosen to minimize cost factors, such as the number of RPR spans required to reach the exit node from each RPR node.

Layer-3 network routing with RPR layer-2 visibility

According to a disclosed embodiment of the invention, software download and installation in a ring network are synchronized in a two-stage operation in order to minimize service disruption time. In a first phase, the MPM's and UIM's in all the nodes are upgraded in parallel. Each node has two main processing modules, allowing one to be upgraded while the other continues to operate the node. In a second phase, the RIM's at the edges of a single ring segment are upgraded, one ring segment after the other, during which time each terminal node continues to operate with respect to the span connecting to its opposite side. While a span is non-operative, traffic is wrapped or diverted as necessary to maintain service of the ring. While one RIM of a node is being upgraded, the other RIM remains operational.

Synchronized ring software download

A method for traffic engineering in a communication system made up of network nodes arranged in multiple interconnected networks, including at least one bi-directional ring network having an inner ring and an outer ring. The bi-directional ring network is defined as a multi-access network for purposes of a routing protocol used in the system. Constraint information is advertised with regard to connections on the inner and outer rings between the nodes within the at least one bi-directional ring network. Traffic flow is routed through the system in accordance with the routing protocol, so that the flow passes through the at least one bi-directional ring network on at least one of the connections on one of the inner and outer rings that is selected responsive to the constraint information.

Growing community of inventors

Ramat Gan, Israel

Alex Levit