Abstract: A link based network protection path calculation mechanism wherein a protection route is calculated that is guaranteed not to traverse the link it is intended to protect. The mechanism takes advantage of the fact that the same color cannot pass twice through the same optical fiber. The protection path is determined by eliminating all colors from the logical topology of the network except for the color corresponding to the link to be protected before executing the search algorithm. This serves to guarantee that the protection path calculated will not traverse the same physical fiber as the link to be protected. Virtual colors can be assigned to the links running through fiber bundles such that they do not pass through the same fiber/bundle twice.

Abstract: A fast protection mechanism capable of maintaining end-to-end and fast local protection on the order of sub 50 ms for both VLAN only based connections and for connections that are based partially on VLAN technology and partially on MPLS technology. The present invention is suitable for use edge switches configured in a stack or ring topology. The NMS provisions both the main and alternative VLANs in each edge switch in the stack portions of the network. When a link failure occurs, the edge switches on either end of the failed link immediately switch all protected traffic going through that link to the alternative VLAN. The packets are then returned on the links over which they were received. Hello messages are used to signal the remote end that a link failure has occurred and that protected traffic must be switched to the main or alternative VLAN in accordance with the VLAN the Hello message was received on.

Abstract: A 1:N protection scheme that provides both equipment and line protection against a single point of failure for a network hub situated in an optical ring network. The invention is suitable for use in DWDM based optical ring networks, and in particular, in networks constructed having a logical star over physical ring topology. The hub is modified to comprise N+1 transceivers, assuming an N channel DWDM network wherein each of the N transmitters operates using a different wavelength. Protection against line failures is achieved by optically splitting the transmit signal into two paths and transmitting each separately in opposite directions over the ring (i.e. 1+1 protection). In the event of a line failure, the other signal should still arrive at the destination. Protection against equipment failures is achieved through the use of a spare transceiver having a tunable wavelength of operation (i.e. 1:N protection).

Abstract: An apparatus for and method of enforcing precedence of committed traffic over excess traffic that overcomes the difficulty in supporting committed over excess traffic and has particular application to distributed queuing systems. Queue control messages are generated and transmitted to other line cards to guarantee that committed traffic is not dropped when sent from multiple sources such as line interface cards to a single destination. When the level of a queue exceeds a threshold and flow control is received for the corresponding destination, the queue starts dropping excess traffic and messages indicating the queue status are sent to all other lines cards. When a line card receives a queue control message that another line card started dropping excess traffic to a specific destination, it also starts dropping excess traffic to that destination as well.

Abstract: A method of performing policy enforcement by a switch, including receiving a plurality of frames, examining at least some of the received frames to determine whether they require non-default policy enforcement according to pre-programmed policy rules which pertain to at least one protocol, and forwarding, with default policy handling, at least some of the received frames which belong to the protocol to which the rules pertain, regardless of the policy enforcement they require.

Abstract: A method of managing connectivity between an end-device and one of a plurality of bridging-devices connected to the end-device. The method includes transmitting test messages by each of the bridging-devices, transmitting test messages by the end-device, determining, in each of the bridging-devices, with which of the other devices there is an operative connection, based on the test messages the bridging-device receives and determining, in each of the bridging-devices, whether a port leading to the end-device should be in a forwarding or blocking state responsive to the determination of the operative connections.

Abstract: A method of managing connectivity between an end-device and one of a plurality of bridging-devices connected to the end-device. The method includes transmitting test messages by each of the bridging-devices, transmitting test messages by the end-device, determining, in each of the bridging-devices, with which of the other devices there is an operative connection, based on the test messages the bridging-device receives and determining, in each of the bridging-devices, whether a port leading to the end-device should be in a forwarding or blocking state responsive to the determination of the operative connections.

Abstract: A method of accelerating the routing of frames by an acceleration switch within a network. The method includes receiving, by the acceleration switch, frames directed to one of one or more routers or switches of the network, determining, for at least some of the received frames, whether the frames belong to a first list of frame groups, defined by values of a plurality of frame parameters, and routing, by the acceleration switch, at least some of the received frames, the routed frames being selected responsive to the determining.

Abstract: A method of managing connectivity of a cluster of bridging-devices including a plurality of links. The method includes pre-designating at least one of the links as a redundant link which is blocked when all the other links are operative and connected in accordance with a predetermined scheme, determining connectivity data on the connectivity of the links of the cluster, and activating or blocking the pre-designated redundant at least one link responsive to the connectivity data.

Abstract: A path reroute mechanism for use in communication networks comprising multiple searches for a routing path to restore traffic following a failure that could not be protected by a previously established protection route (i.e. protection tunnel, bypass, etc.) or for routing or rerouting of traffic paths for optimization or any other purpose. Each node advertises TLVs that include bandwidth allocation information used to derive the actual amount of bandwidth available for protection purposes, protected paths and unprotected paths or a portion of this information such as in the case where unprotected paths are not supported. Searches are performed on larger and larger portions of the available bandwidth until a route for the path is found.

Abstract: A method of implementing a distributed algorithm which is based on sending Bridge Protocol Data Units (BPDUs) only between neighboring bridging-devices in a network. The method includes sending BPDUs from a first bridging-device of the network to at least one non-neighboring second bridging-device, and determining a characteristic of the network responsive to the BPDUs.

Abstract: A method of managing connectivity of a cluster of bridging-devices including a plurality of links. The method includes pre-designating at least one of the links as a redundant link which is blocked when all the other links are operative and connected in accordance with a predetermined scheme, determining connectivity data on the connectivity of the links of the cluster, and activating or blocking the pre-designated redundant at least one link responsive to the connectivity data.

Abstract: A mechanism and associated protocol for performing Service Level Agreement (SLA) measurements in a communications network. The measurements obtained are used to perform various SLA parameter calculations such as delay, round trip delay, one way jitter and bandwidth related calculations. SLA measurement request and response messages are stamped with time and bandwidth counters by the client and remote ends of a connection. The resultant data is used to perform the calculation of SLA parameters.

Abstract: A method of connecting a client to a server by a load balancer associated with a plurality of servers. The method includes establishing a first connection for transmission of packets between the load balancer and the client, selecting a server to service the client, and splicing the first connection with a second connection between the load balancer and the selected server, the second connection being established before the first connection.