Abstract: A network element includes a backplane, which includes a backplane memory holding first medium access control (MAC) address values. The network element further includes multiple tributary modules coupled to the backplane, which include network interfaces that are configured to communicate over network trunks using MAC addresses that are respectively assigned to the network interfaces. The network element further includes a common function module (CFM), which communicates with the tributary modules and the backplane memory via the backplane, and which includes a CFM memory holding second MAC address values. The CFM is arranged to assign the MAC addresses to the network interfaces by selecting the MAC addresses from among the first MAC address values when the CFM is able to access the backplane memory, and by selecting the MAC addresses from among the second MAC address values when the CFM is unable to access the backplane memory.

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 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 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 method for communication includes, in a communication network that includes multiple ring nodes arranged in at least first and second ring networks that are connected by two or more of the ring nodes serving as interconnect nodes, accepting at the two or more interconnect nodes respective copies of a data packet, which is sent from a source user node connected to the first ring network. An attribute is extracted from the respective copies of the data packet at each of the interconnect nodes, and a predefined mapping function is applied to the extracted attribute so as to select a single interconnect node for forwarding the data packet to the second ring network. A single copy of the data packet is forwarded to the second ring network only from the selected interconnect node, while refraining from forwarding other copies from the other interconnect nodes.

Abstract: A method for changing a network characteristic or capability, such as the communication rate of network segments, software version or protocol. All nodes in the network perform the change synchronously while continuing to communicate within the existing capabilities. A new configuration is downloaded to the nodes, and a manager node exchanges validation messages with the other nodes in order to verify that the nodes can be reconfigured and will be able to complete the process successfully. The manager node then sends a command message to the other nodes to execute the change. In response, the other nodes begin substantially simultaneously to communicate in accordance with the new characteristics and/or capabilities. This method helps to minimize the duration of the upgrade process, while avoiding traffic hits and minimizing abnormal operation that may occur during the upgrade.

Abstract: A method for communication includes setting respective overbooking ratios for multiple categories of data traffic, and assigning respective bandwidth allocations to a plurality of connections for transmitting the data traffic in one or more of the categories over a network. The data traffic from the connections is coupled into respective queues, such that each of the queues is associated with one or more of the connections. Respective weights are computed for the queues responsively to the bandwidth allocations and to the overbooking ratios of the categories of the data traffic to be transmitted on the connections that are associated with each of the queues. A multiplexer multiplexes among the queues responsively to the respective weights so as to transmit the data traffic from the connections over a link in the network.

Abstract: A method for communication includes encapsulating multiple data packets, which carry data and have respective drop precedence (DP) values selected from a range of possible DP values, to produce a concatenated frame of a transport protocol. A composite drop precedence (CDP) value is assigned from the range to the concatenated frame using a pseudo-random assignment function that depends on a distribution of the DP values of the data packets in the concatenated frame. The concatenated frame is transported through a communication network using the transport protocol, in accordance with the pseudo-randomly assigned CDP value.

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 communication is used in a communication network that includes multiple ring nodes arranged in at least first and second ring networks, which are connected by one or more of the ring nodes serving as interconnect nodes. A data packet is accepted from a source user node served by the first ring network, for forwarding to a destination user node served by the second ring network. An identifier, which identifies an interconnect node in the first ring network through which the data packet is to be forwarded to the second ring network, is attached to the data packet in the first ring network. The data packet is forwarded over the first ring network, accepted at the interconnect node and, responsively to the identifier, forwarded from the interconnect node to the second ring network. The data packet is forwarded over the second ring network to the destination user node.

Abstract: A network element includes a backplane, which includes a backplane memory holding first medium access control (MAC) address values. The network element further includes multiple tributary modules coupled to the backplane, which include network interfaces that are configured to communicate over network trunks using MAC addresses that are respectively assigned to the network interfaces. The network element further includes a common function module (CFM), which communicates with the tributary modules and the backplane memory via the backplane, and which includes a CFM memory holding second MAC address values. The CFM is arranged to assign the MAC addresses to the network interfaces by selecting the MAC addresses from among the first MAC address values when the CFM is able to access the backplane memory, and by selecting the MAC addresses from among the second MAC address values when the CFM is unable to access the backplane memory.

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 establishing a connection with a guaranteed bandwidth for transmitting data over a logical link that includes a plurality of parallel physical links between first and second endpoints. A link bandwidth is allocated on each of the physical communication links so as to include a predefined safety margin, based on either a failure protection policy, or a measure of fluctuation that occurs in a rate of data transmission over the physical links, or both. A sum of the allocated link bandwidth over the plurality of the parallel physical links is substantially greater than the guaranteed bandwidth of the connection. The data are conveyed over the logical link by distributing the data for transmission among the physical links in accordance with the allocated link bandwidth.

Abstract: A method for assigning bandwidth in a network including nodes coupled by links arranged in a physical topology, the method including: defining between the nodes logical connections associated with a data transmission service to be provided over the network, the logical connections having a connection topology different from the physical topology, and determining respective bandwidth requirements for the logical connections based on parameters of the service. The method further includes mapping the connection topology to the physical topology, so that each of the logical connections is associated with one or more links of the physical topology, and allocating a bandwidth for the service on each of the links in response to the bandwidth requirements of the logical connections and to the mapping.

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.