Abstract: A method for data communications includes receiving a time-division-multiplexed (TDM) input signal on a first circuit, the signal including an input sequence of frames of data, each such frame divided into sections for carrying respective sub-rate payloads. After determining which of the sections are active, such that the data in the sub-rate payloads of the active sections include user data, and which of the sections are inactive, the user data in the active sections are encapsulated into data packets for transmission over a packet network, while omitting from the packets at least some of the data from the inactive sections.

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 communication network includes a communication medium and a plurality of communication nodes, mutually coupled by the communication medium so as to form a ring, over which each of the nodes is configured to transmit traffic to the other nodes in both clockwise and counterclockwise directions around the ring. At least one of the nodes is configured to receive the traffic in only one of the directions at any given time.

Abstract: Network access apparatus includes a slave unit, including a plurality of subscriber ports adapted to be linked to respective subscriber lines, and a multiplexer for multiplexing among the ports. A master sub-system, is connected to at least one trunk line of a first public network, in a location remote from the slave unit. The master sub-system includes a first master unit, adapted to communicate with the slave unit via an assigned link through a second public network, so as to provide users of the subscriber lines with access to the first public network through the at least one trunk line. The master sub-system also includes a second master unit, coupled through the first master unit to communicate with the slave unit via the assigned link, so as to provide the users with access to the first public network through the at least one trunk line in the event of a failure associated with the first master unit.

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 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.

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: 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 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: Network access apparatus includes first and second master units, each having a physical interface to a packet-switched network. A plurality of slave units, each slave unit having one or more ports to respective subscriber lines, are linked by a plurality of physical interface lines in one or more daisy chains, in which the slave units are mutually connected in series by the physical interface lines therebetween. Each daisy chain includes at least a first slave unit connected by one of the physical interface lines to the first master unit and a last slave unit connected by another of the physical interface lines to the second master unit.

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 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 data communications includes receiving a time-division-multiplexed (TDM) input signal on a first circuit, the signal including an input sequence of frames of data, each such frame divided into sections for carrying respective sub-rate payloads. After determining which of the sections are active, such that the data in the sub-rate payloads of the active sections include user data, and which of the sections are inactive, the user data in the active sections are encapsulated into data packets for transmission over a packet network, while omitting from the packets at least some of the data from the inactive sections.

Abstract: A communication network includes a communication medium and a plurality of communication nodes, mutually coupled by the communication medium so as to form a ring, over which each of the nodes is configured to transmit traffic to the other nodes in both clockwise and counterclockwise directions around the ring. At least one of the nodes is configured to receive the traffic in only one of the directions at any given time.

Abstract: A method for managing a buffer includes receiving a stream of data fragments into the buffer, at least some of the fragments being arranged in packets, each such packet comprising a last fragment. While a fill level of the buffer remains below a first threshold, the received fragments are accepted into the buffer. When the fill level of the buffer increases above the first threshold, the buffer continues to accept the received fragments until the last fragment in one of the packets is received or until the fill level of the buffer increases above a second threshold, greater than the first threshold. When the last fragment in one of the packets is received, the fragments that are received thereafter are discarded until the last fragment in another, subsequent one of the packets is received and the fill level of the buffer is no longer above the first threshold. The buffer then continues to accept the received fragments.

Abstract: A method for establishing a data link service connection for a bi-directional service to be provided between first and second nodes through a network. Responsive to a request to initiate the service connection, a local index is generated at the first node indicative of the service to be provided, and a first signaling message is sent to the second node containing the index from the first node and service parameters of both of the nodes. Upon receiving the message at the second node, the service connection is initiated responsive to the index and the service parameters. A second signaling message is sent to the first node, and the service indicated by the index is activated.