Abstract: A method for communication includes configuring a network node having at least first and second line cards, the line cards having respective ports, to operate as a distributed media access control (MAC) bridge in a Layer 2 network. Each of the line cards has a respective forwarding database (FDB). Upon receiving a data packet on a port of the network node from a MAC source address, the data packet is conveyed to at least the first line card for transmission to the MAC destination address. The MAC source address of the data packet is checked against the records in the FDB of the first line card. If the FDB does not contain a record of an association of the MAC source address with the port on which the data packet was received, the record is added to the FDB of the first line card, which sends a message to at least the second line card informing the second line card of the association.

Abstract: A method for data communications includes receiving a time-division-multiplexed (TDM) input signal carrying a payload comprising data and determining whether the data comprise synchronous or non-synchronous data. A first encapsulation scheme is selected if the data comprise synchronous data, and a second encapsulation scheme is selected if the data comprise non-synchronous data. The data are encapsulated for transmission over a packet-switched network in accordance with the selected encapsulation scheme.

Abstract: There is provided a method device and system for providing packetized streaming media content (e.g. audio, video and multimedia) to an IP based media presentation appliance (e.g. set-top box). According to some embodiments of the present invention, there may be provided a media stream generator adapted to generate or otherwise derive from a source media a second media stream including more key frames (e.g. MPEG I-Frames) than present in the source media stream.

Abstract: A method for communication includes coupling a network node to one or more interface modules using a first group of first physical links arranged in parallel. Each of the one or more interface modules is coupled to a communication network using a second group of second physical links arranged in parallel. A data frame having frame attributes sent between the communication network and the network node is received. A first physical link out of the first group and a second physical link out of the second group are selected in a single computation based on at least one of the frame attributes. The data frame is sent over the selected first and second physical links. This method allows two or more link aggregation groups to be concatenated, using a single processing stage to determine port assignment for each frame in each of the link aggregation groups.

Abstract: A method for data communications includes receiving a time-division-multiplexed (TDM) input signal carrying a payload comprising data and determining whether the data comprise synchronous or non-synchronous data. A first encapsulation scheme is selected if the data comprise synchronous data, and a second encapsulation scheme is selected if the data comprise non-synchronous data. The data are encapsulated for transmission over a packet-switched network in accordance with the selected encapsulation scheme.

Abstract: Explicit routing of network traffic over RPR rings using MPLS signaling techniques, including unnumbered links. A modified LSP_TUNNEL_INTERFACE_ID object is provided with a RPR IP address instead of the conventional LSR Router ID, and with a direction indicator in place of the conventional interface ID. A novel subobject is included in the ERO and RRO, which holds the RPR IP address of the sending node in place of the conventional router ID, and a direction indicator in place of the conventional interface ID. The network nodes inspect the directional indicator that is received in a path message or a Resv message to determine the direction in which traffic is to be sent and received in an explicit route.

Abstract: A method for communication includes provisioning different first and second instances of a multipoint-to-multipoint (MP-MP) communication service over respective first and second alternative sets of links (44A . . . 44D, 48A . . . 48D) that connect a plurality of endpoints (24A . . . 24C, 28) in a network (20), each of the sets traversing network nodes (32A . . . 32D), which provide physical layer resources for operating the links. The communication service is provided to the endpoints over the first set of links (44A . . . 44D) using the first instance. Upon detecting a failure in the first set of links, the physical layer resources of one or more of the links in the first set is deactivated by at least one of the network nodes, in order to cause a loss of connectivity in the first set of links. Responsively to sensing the loss of connectivity, the communication service is resumed over the second instance by automatically transferring communication among the endpoints to the second set of links (48A . . .

Abstract: A network node in a communication network includes a plurality of ports, at least a subset of which is grouped in a link aggregation (LAG) group. The node includes packet processing logic, which is coupled to receive data packets having respective destination addresses that specify forwarding the packets to groups of multiple recipients through at least one of the ports and to process the data packets so as to forward only a single copy of each of the data packets via the output ports in the subset, while distributing forwarded copies of the data packets among the output ports in the subset so as to balance a traffic load within the LAG group.

Abstract: A method for data communications includes linking a plurality of edge devices to communicate with a remote network device via a network in accordance with a packet-oriented Layer 2 communication protocol. At each of the plurality of edge devices, incoming data frames are received from client nodes in accordance with respective native Layer 2 protocols, at least one of which is different from the packet-oriented Layer 2 communication protocol. The received incoming data frames are converted at each of the edge devices from at least a first format specified by the native Layer 2 protocols to a second format specified by the packet-oriented Layer 2 communication protocol. The incoming data frames are transmitted in the second format via the network to the hub.

Abstract: A method for communication between first and second nodes via a communication network includes assigning multiple communication ports in two or more network nodes between the first and second nodes to serve as member ports of a multi-homing group (MHG). Each of the member ports is associated with a different, respective communication path between the first and second nodes via the communication network. A frame transmitted from the first node to the second node is accepted at the two or more network nodes. The frame has a header including header fields. A single port is selected from among the member ports by applying a hashing function to one or more of the header fields at each of the two or more network nodes. The frame is forwarded via the selected port over the respective communication path that is associated with the selected port.

Abstract: A method for data broadcast over a network includes receiving at a virtual bridge a data packet to be flooded over the network, and passing the data packet from the virtual bridge to a multicast-capable router, along with a broadcast indication. Responsive to the broadcast indication, the router determines a group of destination addresses to which the packet should be multicast, and creates copies of the packet for transmission over the network to the destination addresses in the group.

Abstract: A method for communication includes coupling a group of switches in a Layer-2 bridged network. The interfaces of the switches are configured so that at least one interface of at least one of the switches is configured as a first interface type, and a plurality of other interfaces are configured as a second interface type. Upon receiving frames through the interfaces of the first and second types for transmission over the network, the received frames are labeled with corresponding first and second type indications. The frames are forwarded through the Layer-2 bridged network using the switches responsively to the type indications. Frames labeled with the second type indication are permitted to be transmitted through the interfaces of the first type and prevented from being transmitted through the interfaces of the second type.

Abstract: A method for communication includes configuring a network node having at least first and second line cards, the line cards having respective ports, to operate as a distributed media access control (MAC) bridge in a Layer 2 network. Each of the line cards has a respective forwarding database (FDB). Upon receiving a data packet on a port of the network node from a MAC source address, the data packet is conveyed to at least the first line card for transmission to the MAC destination address. The MAC source address of the data packet is checked against the records in the FDB of the first line card. If the FDB does not contain a record of an association of the MAC source address with the port on which the data packet was received, the record is added to the FDB of the first line card, which sends a message to at least the second line card informing the second line card of the association.

Abstract: A method for communication includes representing a layer 2 ring network, which includes two or more ring nodes interconnected by two unidirectional ringlets, as a plurality of unidirectional point-to-point links connecting respective pairs of the ring nodes and having respective traffic engineering (TE) related attributes. The TE-related attributes of the point-to-point links are distributed to routers of a communication network that includes the ring network. The distributed TE-related attributes are processed to determine an optimal routing path traversing the ring network from a source node to a destination node in the communication network.

Abstract: A data communication network includes a plurality of primary virtual bridges, interconnected by primary virtual connections so as to transmit and receive data packets over the network to and from edge devices connected thereto. One or more backup virtual bridges, each associated with at least one of the primary virtual bridges, are connected by at least one secondary virtual connection to at least another one of the primary virtual bridges, so that upon a failure of one of the primary virtual bridges with which it is associated, the backup virtual bridge transmits and receives the data packets over the network via the at least one secondary virtual connection in place of the at least one of the primary virtual bridges.

Abstract: A method for communication includes coupling a network node to one or more interface modules using a first group of first physical links arranged in parallel. Each of the one or more interface modules is coupled to a communication network using a second group of second physical links arranged in parallel. A data frame having frame attributes sent between the communication network and the network node is received. A first physical link out of the first group and a second physical link out of the second group are selected in a single computation based on at least one of the frame attributes. The data frame is sent over the selected first and second physical links.

Abstract: A method for handling traffic in a communication network includes setting an aggregate limit on a total rate of transmission of information by a group of flows to be transmitted over the network, and setting a respective individual limit on an individual rate of transmission by each of the flows in the group. When the information carried by packets in any given one of the flows is in excess of the respective individual limit, the packets in excess of the respective individual limit in the given one of the flows are tagged with a first excess flow tag. When the total rate of transmission of the information is in excess of the aggregate limit, the packets in excess of the aggregate limit are tagged with a second excess flow tag. Resources in the network are allocated to convey the packets responsive to the first and second excess flow tags.

Abstract: A method for communication includes configuring a plurality of ring nodes to communicate over a communication network that includes two or more overlapping communication rings, each ring including two unidirectional ringlets in mutually-opposite directions. A data packet including one or more header fields is accepted at an ingress ring node. An egress ring node to which the data packet is to be forwarded by the ingress ring node is determined. A subset of the rings including one or more common rings that are connected to both the ingress and egress ring nodes is identified. A ringlet of a ring among the one or more common rings is selected responsively to a respective value of at least one of the header fields of the packet. The data packet is forwarded from the ingress ring node to the egress ring node over the selected ringlet.

Abstract: A data communication network includes a plurality of primary virtual bridges, interconnected by primary virtual connections so as to transmit and receive data packets over the network to and from edge devices connected thereto. One or more backup virtual bridges, each associated with at least one of the primary virtual bridges, are connected by at least one secondary virtual connection to at least another one of the primary virtual bridges, so that upon a failure of one of the primary virtual bridges with which it is associated, the backup virtual bridge transmits and receives the data packets over the network via the at least one secondary virtual connection in place of the at least one of the primary virtual bridges.

Abstract: A performance management unit manages a primary interface and a standby or secondary interface to two channels of an optical communications network having APS capabilities. Each performance parameter is associated with three counters. First and second counters are linked to registers of the primary and the secondary ports, and the third counter is linked to the registers of the currently active port. When a protection switch occurs, the first and second counters are immediately read and reset. The third counter continues accumulating data, but becomes associated with the new active port. At the end of a read interval, the third counter correctly reflects the number of data received, regardless of switchovers between the primary and secondary channels.