Abstract: A method for passing communications over an Optical Transport Network (OTN) from a first communication interface to a second communication interface. The first interface extracts characters from received data symbols, maps the characters into OTN communication frames and discards the synchronization symbols. The mapping is performed using a Bit-synchronous Mapping Procedure (BMP), while filling some locations in the OTN frames with stuffing characters, so that the rate of the characters matches a desired rate of the OTN communication frames. The characters are extracted from the communication frames in the second communication interface by synchronizing to the mapped input frames independently of the synchronization symbols. The input frames are reconstructed to produce reconstructed input frames including the data symbols and the synchronization symbols, by re-encoding the extracted characters. In some embodiments, data from Ethernet frames is passed along with the extracted characters in the OTN frames.

Abstract: A method for communication includes receiving in a first communication interface input frames, which include data symbols that were derived by encoding respective characters, and further include one or more synchronization symbols having no corresponding characters. The characters from the data symbols are recovered, and the recovered characters are transmitted to a second communication interface by mapping the characters into communication frames and discarding the synchronization symbols. The characters are extracted from the communication frames in the second communication interface by synchronizing to the input frames independently of the synchronization symbols. The input frames are reconstructed in the second communication interface, including the data symbols and the synchronization symbols, by re-encoding the extracted characters.

Abstract: A method for communication includes, receiving in a first communication interface input frames, which include data symbols derived by encoding respective characters, and one or more synchronization symbols distinguishable from the data symbols. The characters are recovered from the data symbols, and transmitted to a second communication interface by mapping the characters into communication frames and discarding the synchronization symbols, wherein a protocol for delivering the characters supports a mapping scheme for delivering the characters at a first data rate, and mapping the characters includes mapping the characters so as to deliver the characters at a second data rate lower than the first data rate. The characters are extracted from the communication frames in the second communication interface by synchronizing to the mapped input frames independently of the synchronization symbols.

Abstract: There is provided a method device and system for streaming media content to a media presentation appliance. There may be provided an appliance specific media stream generator adapted to derive an appliance specific stream from a multicast media stream. The generator may convert a multicast media stream addressed to a set of media presentation appliances into either (1) one or more unicast media streams, wherein each unicast media stream is addressed to a separate media presentation appliance; or (2) a multicast media stream addressed to a subset of the set of media presentation appliances. In both cases, the media content within the derived media stream may be substantially identical to the media content of the original multicast media stream. The generator may also introduce content (e.g. advertising) into the derived media stream(s).

Abstract: A method for communication includes receiving in a first communication interface input frames, which include data symbols that were derived by encoding respective characters, and further include one or more synchronization symbols having no corresponding characters. The characters from the data symbols are recovered, and the recovered characters are transmitted to a second communication interface by mapping the characters into communication frames and discarding the synchronization symbols. The characters are extracted from the communication frames in the second communication interface by synchronizing to the input frames independently of the synchronization symbols. The input frames are reconstructed in the second communication interface, including the data symbols and the synchronization symbols, by re-encoding the extracted characters.

Abstract: An apparatus includes a data flow circuit and a clock recovery circuit. The data flow circuit is configured to extract client data, which is encapsulated in an inner frame that is encapsulated in at least an outer frame, and to output the extracted client data in accordance with a client clock signal. The clock recovery circuit includes a first clock recovery module that is configured to recover a first clock signal that matches payload data in the outer frame, and a second clock recovery module that is configured to derive from the first clock signal a second clock signal that matches the client data in the inner frame, and to produce the client clock signal from the second clock signal, for use by the data flow circuit.

Abstract: An apparatus includes a data flow circuit and a clock recovery circuit. The data flow circuit is configured to extract client data, which is encapsulated in an inner frame that is encapsulated in at least an outer frame, and to output the extracted client data in accordance with a client clock signal. The clock recovery circuit includes a first clock recovery module that is configured to recover a first clock signal that matches payload data in the outer frame, and a second clock recovery module that is configured to derive from the first clock signal a second clock signal that matches the client data in the inner frame, and to produce the client clock signal from the second clock signal, for use by the data flow circuit.

Abstract: A method for communication includes generating in a transmitter a sequence of data packets for transmission to a receiver. Control packets are inserted into the sequence in the transmitter, such that a given control packet is indicative of a count of the data packets that are transmitted in a time interval that ends with a previous control packet that precedes the given control packet. The sequence, including the data packets and the inserted control packets, is transmitted to the receiver.

Abstract: 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.

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 method for communication over a bi-directional ring network includes provisioning a virtual private local area network service (VPLS) over the bi-directional ring network. The VPLS includes connection termination points provisioned respectively on a plurality of the nodes so as to connect each of the plurality of the nodes to a second network external to the ring network. As long as the nodes and spans are fully operational, one or more of the connection termination points are maintained in a deactivated state, so that no more than one of the connection termination points to the second network is active. The nodes exchange messages indicative of a failure associated with the bi-directional ring network, causing at least one of the deactivated connection termination points to be activated so as to maintain connectivity among the users of the VPLS without creating a loop in the VPLS via the second network.

Abstract: A method for communication via a ring network that includes a plurality of nodes. The method includes receiving at a first node in the ring network a data packet transmitted over a virtual private LAN service (VPLS), the data packet including an identification of the VPLS. The first node reads the identification from the data packet. Responsively to reading the identification, the first node forwards the data packet to at least one second node in the ring network that is associated with the VPLS.

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 streaming media content to a media presentation appliance. There may be provided an appliance specific media stream generator adapted to derive an appliance specific stream from a multicast media stream. The generator may convert a multicast media stream addressed to a set of media presentation appliances into either (1) one or more unicast media streams, wherein each unicast media stream is addressed to a separate media presentation appliance; or (2) a multicast media stream addressed to a subset of the set of media presentation appliances. In both cases, the media content within the derived media stream may be substantially identical to the media content of the original multicast media stream. The generator may also introduce content (e.g. advertising) into the derived media stream(s).

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 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 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 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 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.