Nortel Networks Corporation

Alan Hurren

Mark Temple Cobbold

David MacDonald Delaney

Peter Martin Kenneth Cottreau

Paul Allen Bottorff

Joseph M Regan

Wang-Hsin Peng

David Macdonald Delaney

Peter Martin Cottreau

A control system enables transport of payload data across a dual counter rotating ring (DCRR) network having two or more nodes, each node providing access to the DCRR network by a respective local area network (LAN) subtending the node. The control system comprises a topology learning entity operative within each node for monitoring individual, links of the DCRR, discovering the active topology of the DCRR, communicating topology changes to other nodes in the DCRR, and informing frame forwarding and learning processes of the topology to enable failover to redundant resource upon detection of a network component failure. A frame forwarding process selects a shortest path route between a source and a destination node in the DCRR, and forwards frames to the destination node via the selected shortest path route. An address learning process inspects a source medium access control (MAC) address in each received frame to learn a shortest path route for each MAC address.

Enhanced dual counter rotating ring network control system

In methods and apparatus for routing packets through a communications network, a respective distinct broadcast address is assigned to each of a plurality of distinct sets of virtual ports. No virtual port belongs to more than one of the distinct sets. A respective egress address is assigned to each packet entering the network via an ingress virtual port. The respective egress address corresponds to a respective destination address of the entering packet when a correspondence between the destination address and an egress address is known. When no correspondence between the destination address and an egress address is known, the respective egress address is a broadcast egress address corresponding to the set comprising the ingress virtual port. The packet is routed according to the respective egress address. The routing is restricted to virtual ports belonging to the distinct set of virtual ports that includes the ingress virtual port. The distinct sets of virtual ports and their associated broadcast addresses define isolated virtual private networks within the network. Each physical port of the network may map one-to-one onto a corresponding virtual port, or may map onto a corresponding plurality of virtual ports, in which case the each virtual port of the plurality is associated with a respective distinct combination of a physical address of the physical port and a respective virtual network identifier.

Virtual private networks and methods for their operation

A method and apparatus for providing a Virtual Private Network (VPN) over a connectionless network connecting a plurality of Local Area Networks (LANs), such as an Ethernet network, is disclosed. The method and apparatus comprises associated each VPN with a unique identifier and each LAN of the VPN with a interface device connecting the LAN to the connectionless network, which may be for example, a Synchronous Optical Network (SONET). The interface device may service a plurality of LANs. Accordingly, each LAN is associated with a User-Network Interface that forms part of the interface device. Each data packet destined for a second LAN, such Ethernet frames, received by the interface device for a first LAN is encapsulated with, if known, a Media Access Control (MAC) address of the interface device connected to the second LAN, the VPN's unique identifier, and the port on the interface device connected to the second LAN. Additionally, the corresponding MAC and port address of the first interface device is also used to encapsulate the Ethernet frames. If the MAC and port address is not known (i.e., it is not stored in a database on the first interface device), the first interface device multicasts an encapsulated Ethernet packet to the entire VPN. The first interface device maintains (i.e., updates and appends) its database of MAC and port addresses in response to encapsulated data frames received by the first interface device.

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Nepean, Canada

Alan Hurren