Abstract: Wide-area data communications utilize regional networks transporting IP-over-Ethernet on fiber. For certain Layer 2 services, a regional implementation of the network makes limited use of spanning tree protocol on a backbone ring. Learning bridge operations in switches on associated access rings involve a short default for an aging timer. For use of Open Shortest Path First (OSPF), the connection of each access ring to the backbone ring uses a pair of routers with dual links therebetween. One of these links is bonded to the backbone (OSPF Area 0), whereas the other link is bonded to the Area of the respective access ring. Also, certain routers within each regional network form a mini-autonomous system, for boundary gateway protocol (BGP). The mini-autonomous systems of the regional networks form a confederation. The network utilizes route reflectors in the mini-autonomous systems. The Internet carries confederation commands to and from a designated hub.

Abstract: A system, device, and method for receiver access control in a multicast communication network uses a policy service to determine whether a subscriber device can be admitted to a multicast group. The subscriber device accesses the multicast communication network via an access device. The access device uses a policy service to obtain a policy decision from a policy server, where the policy decision indicates whether or not the subscriber device can be admitted to the multicast group. The access device enforces the policy decision by admitting the subscriber device to the multicast group if and only if the policy decision indicates that the subscriber device can be admitted to the multicast group.

Abstract: Planning alternative SS7 networks is a complex task requiring assistance from an intelligent planning tool. The tool includes at least one planning database containing information on network traffic, component locations, and component connectivity. A load module determines peak load for each STP in the core network. A forecast module determines equipment capacity exhaustion for each STP, network database, and core link during each study period and determines network costs based on peak loads and an alternative network design provided by a user. A graphical user interface guides the user through a sequence of design steps, each step having to be correctly completed before the next step in the sequence is started. The sequence of steps may include permitting changes to the core network, permitting changes to the number of POPs and DBs, rehoming elements left disconnected from STPs, assigning SSPs to POPs, assigning SSPs to DBs, and permitting voluntary rehomes.

Abstract: Novel data structures, methods and apparatus for finding the longest prefix match search when searching tables with variable length patterns or prefixes. To find the exact match or the best matching prefix, patterns have to be compared a bit at a time until the exact or first match is found. This requires “n” number of comparisons or memory accesses to identify the closest matching pattern. The trees are built in such a way that the matching result is guaranteed to be a best match, whether it is an exact match or a longest prefix match. Using the trail of all the birds and associated prefix lengths enables determination of the correct prefix result from the trail. By construction, the search tree provides the best matching prefix at or after the first compare during walking of the trail or tree.

Abstract: A memory system having multiple memory banks is configured to prevent bank conflict between access requests. The memory system includes a memory controller and a plurality of memory banks operatively coupled to the memory controller, with each of the memory banks configured for storing a plurality of data items. More particularly, a given data item is stored as multiple copies of the data item with the multiple copies being stored in respective ones of a designated minimum number of the memory banks. The memory controller is adapted to process requests for access to the data items stored in the memory banks in accordance with a specified bank access sequence.

Abstract: In a spanning tree-based computer network having a plurality of switches, a spanning tree can be generated and/or recovered by identifying a network core, determining a distance to the network core for each switch in the network, and generating and/or recovering a spanning tree for the network based on the switches' relative distances to the network core.

Abstract: A system for servicing communication queues may include memory configured to store a hierarchical channel map having a plurality of levels wherein each bit of the lowest level is mapped to a different one of a plurality of communication channels and wherein each bit of each higher level is mapped to a group of bits at the next lower level. The system may include a host adapter configured to maintain the hierarchical bitmap wherein each bit at the lowest level is set if the channel to which it is mapped has a pending communication request and is cleared if not. Each bit of each higher level is set if at least one bit is set in the lower level group to which is mapped and cleared if not. The host adapter may be configured to examine the hierarchical bitmap in order to determine a next one of the communication channels to service. At each level of the hierarchical channel map a service mask may be provided to track which bits have already been traversed at that level.

Abstract: A multiple instance spanning tree protocol (MI-STP) creates a plurality of active topologies (i.e., loop-free paths) within a computer network. These active topologies may be established through the exchange and processing of multiple instance spanning tree bridge protocol data unit messages (MI-STP BPDUs) by the intermediate network devices within the network. The active topologies are preferably created independently of any virtual local area network (VLAN) designations defined within the network. Once the active topologies are defined, each VLAN designation is then mapped to a single active topology, although multiple VLAN designations are preferably mapped to the same active topology to provide load balancing.

Abstract: A method and apparatus for reducing bandwidth usage in an ATM switching network by controlling bandwidth used for IP multicasting through the switching network. Bandwidth usage is controlled by modifying ingress and access modules, such as IP service gateways and access modules that terminate branches of a multicast tree. If a join request is received at an IP service gateway from a sink node served by an access module, the IP service gateway instructs the access module to graft a leaf to the branch to join the sink node to the tree and to merge the multicast packets with other IP packets for the sink node. Consequently, only one connection carrying the multicast traffic is required between the IP service gateway and the access module. Bandwidth usage in the ATM switching network is thereby controlled, and bandwidth usage in service access trunks connecting the access modules to the ATM switching network is reduced.

Abstract: In a first embodiment, multi-speed concatenated packet strings are transmitted by a first node on a serial bus. To accommodate multi-speed packets, a speed signal is transmitted immediately prior to the packet. In a second embodiment, ACK-concatenation is used to allow a node to transmit a data packet immediately after transmitting an acknowledge signal on the bus. The data packet need not be related to the ACK packet. In a third embodiment, a node which receives a first data packet followed by a data end signal on a child port, concatenates a second data packet onto the first data packet during retransmission. The second data packet is also transmitted down the bus in the direction of the node which originally transmitted the first data packet.

Abstract: A controller changes a blocked port to a forwarding state when a link down or change of the representative bridge is detected and a receiving port of a bridge settled in the root bridge is a blocked port. When the bridge itself is not settled in a root bridge, a transmitter transmits to another bridge a TCN-BPDU that, when the bridge itself has received a BPDU inferior to itself BPDU, the representative bridge changes. A transmitter transmits to all other bridges a TC detection flag set BPDU when the bridge itself has received a TCN-BPDU and the bridge itself is settled in a root bridge. When the bridge itself is not settled in a root bridge and the bridge itself has received the TC detection flag set BPDU, such BPDU is transmitted in a direction other than root bridge direction, and the contents of a forwarding table of the bridge itself are deleted.

Abstract: The invention provides for a method for transporting a SONET formatted asynchronous transfer mode (ATM) signal and/or a synchronous transfer mode (STM) signal on a line switched ring over a unidirectional path. The SONET formatted ATM signal comprises cells mapped into a STS-Mc or m×STS-1s while the STM signal comprises STS-1s/VTS mapped STS-W. A unidirectional line switched ring is provided for transporting the STM STS-W using a unidirectional path switched protection protocol and the ATM STS-Mc using a unidirectional line switched protection protocol. A ring node comprises input and output ring interfaces, an STS management block, an ATM cell management block, and a non-ATM payload management block. The STS management block routes the traffic to the ATM cell management block and to the non-ATM payload management block, according to the traffic type. The STS management block also provides the UPSR protection for the STS-1s and ULSR protection for the STS-Mc.

Abstract: A method for avoiding loops from forming when setting up label switched paths is provided. The method uses a Label Splicing Message is followed by an Acknowledgment message to determine if loops are formed in the process of joining a new node or subtree to a multicast MPLS tree. By verifying that the path towards the root of the MPLS tree is loop-free during the construction of the tree, this method complements the loop detection mechanism provided by the label switched protocol (LDP).

Abstract: A new search protocol uses a message which a router periodically transmits onto the local LANs connected to its ports, and in response to the new protocol, all end stations receiving the message transmit their addresses to the router. The addresses transmitted to the router comprise the addresses and any other information needed by the router to reach the end station. For example, for an Ethernet LAN the layer 2 or MAC layer address of the end station is transmitted to the router. In the event that the protocol of the LAN uses source routing, the information transmitted to the router includes both the MAC address and the Route Information Field of the end station. In any event, the router uses the information received from the end stations to build its routing table.

Abstract: Web/portal-based systems and methods for selling, configuring, installing, reconfiguring and servicing such integrated voice/data communications systems are disclosed. An Internet/web or personal digital assistant (“PDA”) or personal computer (“PC”) based portal is provided to enable a relatively high level of data to be more easily collected. The portal preferably is graphical and guides either the customer or one or more sales persons (or site installer/technician, etc.) in the collection of user requirements data indicative of the particular customer's hardware, telephony and network service requirements. The user requirements data is a less technical, more intuitive level of user requirements data, as compared with configuration data. An initial test of the data preferably is performed, such as for purposes of data consistency, ensuring that all required data has been entered and the like.

Abstract: A method and system for implementing of Data Link Switching-like protocols within a high speed packet switching network environment. The invention relates to new access services for NBBS (Networking Broad Band Services) networks. A new access agent (implementing the DLSw Access Services) provides a dramatically simplified but comprehensive Data Link Switching Services across a wide area network and minimizes the latency to set up SNA paths across the network, while maximizing the efficiency of setting up these paths. The invention does not require the implementation of a complex and large TCP/IP protocol stack within the Data Link Switching node. The Access Agent implementing the DLSw node makes intensive use of such NBBS facilities as the Spanning Tree with the use of internode functional addresses, for the exchange of the control information necessary to efficiently set up paths across the network between DLSw access agents.

Abstract: The invention provides a method and system for providing unique ATM End System Addresses, in which each new device is assigned a unique address in an ATM network while allowing all new devices performing the PNNI protocol in a selected set (such as all those from a single manufacturer) to be assigned by default to the same peer group.

Abstract: A method and apparatus for implementing a Multipoint Infrastructure Transport (MINT) protocol in a data network. The present invention includes a method for distributing data in a data network. The data network connects a plurality of nodes and at least a portion of the plurality of the nodes form a multicast group. One of the nodes in the multicast group is designated as a rendezvous node. The method includes a step of maintaining a data store containing a group state at each of the nodes in the multicast group. State updates, received at the rendezvous node are used to update the group state in the data store at the rendezvous node. The state updates are propagated, using a reliable protocol, from the rendezvous node to the other nodes in the multicast group. Finally, the group states in the data stores at the other nodes in the multicast group are updated.

Abstract: Layer 7 switching may be accomplished using one or more caches placed throughout a computer network. Changes to a file on a server may be detected and propagated throughout the network. At the switch or router level, once notification of changes to a file is received, the content may be retrieved from the server and placed in a connected cache. A routing table entry may be created for the content and also placed in the cache. The routing table entry may contain an original location field identifying the original location of the content, a distance field indicating a distance from the cache to the server, and a field indicating a version number of the content. Additional fields may also be contained within the routing table entry. When a user requests a specific file, rather than forward the request directly to the server containing the original file, the request may be handled by the router closest to the user which has a connected cache containing the content.

Abstract: A method for configuring a wireless network comprised of a control node and a multiplicity of individual nodes includes the steps of logically organizing the network into a plurality of bands Bi, wherein each of the bands Bi includes a plurality of the individual nodes and is located a number i of hops away from the control node, where i=0 through N, and N?1, and then assigning a logical address to each of the individual nodes, and storing the assigned logical addresses in the respective individual nodes. The assigned logical address for each individual node includes a first address portion which indicates the band Bi in which that individual node is located, and a second address portion that identifies that node relative to all other individual nodes located in the same band. The network is preferably a packet-hopping wireless network in which data is communicated by transferring data packets from node-to-node over a common RF channel.

Abstract: An algorithm on a computer readable medium for efficiently creating a message efficient virtual backbone in a wireless ad hoc network utilizes three phases to establish an efficient network among the independent transceivers of a wireless ad hoc network. Independent transceivers within the transmission range of each other are neighbors. A leader election and tree construction phase constructs a tree of neighboring transceivers with one transceiver being designated the root and with each transceiver establishing and recording its location in the tree structure and the identifiers of its neighbors; and reporting when the tree is established. A level calculation phase determines the level of each transceiver away from the root transceiver, with each transceiver recording the level of its neighbors.

Abstract: Several sub-switching units are provided in a switching apparatus for routing data packets, which according to the transmission protocol used have protocol packet data in addition to utilizable data in each case. In order to be able to centrally perform the processing work in connection with routing the data packets in a few and particularly in a single sub-switching unit, switching packet data are produced in at least one first sub-switching unit and assigned to the data packets. The switching packet data are analyzed in another second sub-switching unit and used for routing or processing the data packets. In this way, tasks can be centralized on a few and particularly on a single sub-switching unit.

Abstract: A shaper 201 and a scheduler 203 are combined to determine a target tree 203 and insert 207 a tag into a data structure, wherein the tag is associated with a packet that has reached the head of line (HOL) of a queue in a packet router. A tag may become an eligible tag and be placed in a set of tags to be searched. Such tags are searched for the smallest tag. A packet associated with the smallest tag is transmitted if the output link is available.

Abstract: A mobile unit managing network is provided which is capable of supporting a communication area being wider than ever by one highest-layer router. A radio base station transfers a path updating notification fed from a mobile terminal to a lowest-layer router. The lowest-layer router establishes a path in which a network address to the mobile terminal exists in the radio base station and transfers path information to an intermediate-layer router serving as an upward router. The intermediate-layer router establishes a path in which the network address to the mobile terminal exists in the lowest-layer router and transfers path information to the highest-layer router. The highest-layer router, when having received path information notification from the intermediate-layer router, establishes a path in which the network address to the mobile terminal exists in the intermediate-layer router.

Abstract: A frame based data communications network is interfaced to a synchronous digital hierarchy network via a plurality of frame based data port cards incorporated into a plurality of synchronous multiplexers. Each port card comprises a conventional frame based data port, a frame switch, a rate adapter means and a mapping means for mapping data frames into a plurality of SDH virtual containers. Frame based data is incorporated directly into a synchronous virtual container without encapsulation in an intermediate protocol. A number of topologies of a frame based data channel network are possible, overlaid on the underlying synchronous transport network, including an open loop topology, a ring mode topology, and a backhaul topology.

Abstract: A routing method with routing algorithms applicable to a one-level hierarchical network, including a first algorithm in which a shortest one among all paths established in association with one destination is selected, a second algorithm in which the first method is conducted in a distributed fashion to achieve a fast routing, and a third algorithm in which any one of paths established in association with one destination may be selected as a shortest path when the QoS value calculated in association therewith is more optimum than a required reference QoS value, for preventing problems caused by errors at the single path. The method also provides algorithms that are modified versions of the second and third algorithm for the multi-level hierarchical network. Accordingly, the method is advantageous in that users can select an algorithm, most suitable for the system environment, from the above algorithms.

Abstract: A method and apparatus are provided for routing a packet within a plurality of n nodes arranged in a line or tree (or a combination of the foregoing), given a maximum stack depth, s. A fixed stack process for routing packets on a line given a stack depth, s, initially divides a line of n nodes into segments, such as n1/s approximately equal segments. A unique label is assigned to each segment and, within each segment, one of up to n1/s labels is assigned to each node. A fixed stack process for routing packets on a tree, given a target stack depth, s, initially identifies a subset, S, of at nodes from the tree, such as at most 3n1/s nodes, such that after the subset, S, is removed, each remaining subtree has at most n(s-1)/s nodes. A unique label is assigned to each of the nodes in the subset S and, within each remaining subtree, one of up to n(s-1)/s labels is assigned to each node.

Abstract: A method for detecting a routing loop when repairing a bidirectional multicast distribution tree is disclosed. According to the method, a splice message is launched from an originating node attempting to join a bidirectional multicast tree and is sent to a root-node to find out if a routing loop is formed when a node is joining the multicast distribution tree. Depending on the multicast application requirement, when a routing loop is detected during the repairing of a multicast distribution tree, the severed node may abort, or the repair can be deferred until the connection to the root-node is re-established. The loop detection and loop prevention method of the invention may be used as a loop avoidance mechanism with any protocol for repairing a partitioned tree.

Abstract: Method and system for implementing an inter-domain constraint-based shortest path first (“IrD-CSPF”) technique for supporting hierarchical routing in interconnected multi-domain OTNs are described. In one embodiment, the invention is a method for calculating a network path in an interconnected multi-domain network. The method comprises receiving a path setup request message for a new traffic flow in the network identifying a source node in one domain of the network and a destination node in a second domain of the network; determining a common ancestor hierarchical routing domain that includes ancestor nodes of both the source and destination nodes; calculating an inter-domain path from one ancestor node to the other ancestor node that determines, for each lower-level domain, border nodes in the domain from the source node to the destination node; and for each bottom-level domain, calculating an intra-domain path between the border nodes that were determined for the domain.

Abstract: A method for building a hierarchical multicast tree which is centered around a specific node in an Internet Protocol (IP) communications network. The method on a subnetwork comprising dynamically electing a subnetwork leader node for each subnetwork using multicast communications confined to the subnetwork. Receiving a configuration file containing a list of all the network addresses of the nodes in a network. Receiving a number of permissible connections each subnetwork leader node in the network is permitted with other subnetwork leader nodes. And establishing a multicast connection between each subnetwork leader node as identified in the configuration file so that there is a multicast connection path from each subnetwork leader node for each subnetwork and a subnetwork containing a network leader node. In another embodiment, a system and computer readable medium is disclosed to carry out the above method.

Abstract: A method for the self-organization of a plural-node communication network which involves (1) selecting a central coordinator (CCo) node from a collection of nodes initially lacking a CCo, (2) employing the selected CCo to oversee a procedure for discovering, from the mentioned node collection, all nodes which are optimally capable of being organized into a network, in the sense that all such discovered, capable nodes may effectively be organized to communicate bidirectionally with all other nodes, and (3), with respect to such discovered, organizable nodes, creating a network-global connectivity database in the form of a network-organizing communication topology table that describes enablement of bidirectional communication between all nodes.

Abstract: A high-speed IP routing system (1) for searching a best route for an object IP address by the use of a binary tree comprises a volatile memory (15) storing the binary tree exclusively comprising a plurality of route nodes each of which has route information, a next node selection circuit (2) for successively selecting, with respect to the object IP address, every next nodes as selected nodes starting from a root node of the binary tree stored in the volatile memory (15), and an adopted route determining circuit (4) for comparing the route information of each of the selected nodes selected by the next node selection circuit (2) and the object IP address to determine an adopted route IP address to be adopted as a next route.

Abstract: The invention provides methods (300) for organizing and assigning network address to network nodes in clusters (108, 110, 112, 114, 116, 118, 120, 212, 214, 216, 218, 220), and forming new clusters and also provides a method 700 for routing messages in clusters. According to the invention, clusters are organized into hierarchical tree arrangements, with addresses assigned in a manner that facilitates routing messages.

Abstract: A routing table for use with a router in a world-wide network, includes an existing routing table with a multicast-destination (MD) column.

Abstract: A method as apparatus for controlling the number of egress points at an ingress node in a multicast tree in a differentiated services network is described. A resource management entity is provided in each edge node in the entity. The resource management entity in the ingress node stores data from a service level specification that specifies the bandwidth, type of service and a limit on the number of egress points that can be grafted to the ingress node. The grafting of egress points to the node is controlled by the limit. If a new egress point cannot be grafted to the ingress node, the downstream node requesting the graft is preferably provided with graft redirect options to permit the downstream node to graft to an existing branch of the multicast tree. The advantage is automated, dynamic control of the multicast tree so that service is delivered in accordance with a service level agreement that governs service delivery for the dynamic multicast tree.

Abstract: A method for generating display correction waveforms for a CRT display comprises the steps of selecting one of a plurality of trace portions for forming part of a correction waveform, the trace portions having different average values. Completing each of the correction waveform by combining each selected trace portion with a respective retrace portion such that all completed correction waveforms have a predetermined average value. The correction waveforms may have vertical and/or horizontal rates.

Abstract: A method and system for providing multilevel information about multicast distribution. The method comprises the steps of generating a display, on a computer display screen, of a tree having a plurality of nodes, and embedding in the nodes information about the multicast distribution. The tree may display information about one or more of a variety of aspects of the multicast distribution. These aspects include display of the members of each of a plurality of particular multicast groups, group and/or member connectivity, group parameters, group statistics control, monitor and maintenance; acknowledge and/or operational status, etc. As a specific example, the nodes may represent capacities of a defined aspect. Displays may allow users having particular privileges to add, delete and/or modify nodes. Geometric shapes, having geometric aspects, may be used to represent the nodes; and the aspects of these shapes may be used to represent predetermined aspect of the multicast distribution.

Abstract: The invention relates to a hierarchical radio network operations system (OS) and a method for controlling a mobile communications network by a hierarchical radio network OS, the hierarchical radio network OS comprising at least one radio network OS on a subordinate level and a radio network OS on a superior level, wherein after a controlling action is initiated a demand for data depending on the controlling action is forwarded from the superior level OS to at least one subordinate level OS. The latter in response to the call forwards the demanded data to the radio network OS on the superior level.

Abstract: A technique for reliably multicasting a message within a router network in a sequenced order with other messages is provided. At least one special router in the network has associated persistent storage for sequencing a message being routed to one or more clients. When a message is received at this sequencer node, the sequencer places a sequence number for the message in persistent storage and sends a sequencing acknowledgment back to those routers to which the message was originally routed, as well as back towards the source of the message. The sequencer acknowledgment includes the message id, and the sequencing number. When the sequencer acknowledgment is received by a router, it looks up the routing information from the original message, and sends the acknowledgment to those neighboring routers to which the original message was sent, excluding the link from which the sequencer acknowledgment was received.

Abstract: A method (and system) of creating a multicast packet by a source node in a world-wide network, includes providing each multicast packet with a predetermined indicator indicating that the packet includes a multicast packet, one of a plurality of multicast destinations being placed in a packet destination field and a list of remaining multicast destinations being provided in a packet header. A conventional router receiving a multicast packet handles it as a unicast packet and routes it in a conventional manner. A multicast-capable router receiving a multicast packet goes through a packet regeneration and routing process, creating multicast packets and/or unicast packets and then routing them using the conventional routing table.

Abstract: A computer-implemented method for filtering, responsive to a logical specification of a network farm and a communication model for the farm, a tree topology network specification to obtain a filtered tree topology network specification is disclosed. The filtered tree topology network specification has fewer devices therein relative to the tree topology network specification, devices needed for constructing the farm being available in the filtered tree topology network specification. The method includes removing a first set of devices and a first set of switching elements from the tree topology network specification starting at the lowest level of the tree topology network specification and working toward the root node of the tree topology network specification. Each device in the first set of devices represents one of a redundant device, a device having a type unneeded by the farm, and a device unavailable for constructing the farm.

Abstract: Methods and apparatus for creating a network farm from a tree topology network are disclosed. One method includes receiving a logical specification of the farm, the logical specification specifying at least one of device types required by the farm and a number of devices for each of the device types. The method further includes receiving a communication model for the farm, the communication model specifying expected bandwidth usage for devices of the farm. The method additionally includes ascertaining, responsive to the logical specification and the communication model, a solution set of devices among devices of the tree topology network for constructing the farm.

Abstract: A system for controlling multicast traffic in a multiprocessing system is disclosed. The multiprocessing system includes a general-purpose processor, a plurality of network processors and a switch fabric. The system comprises a multicast identifier (MID) manager to manage a distributed database of MIDs. The distributed database includes at least one compound MID. The at least one compound MID structure further comprises a plurality of MIDs representing at least two multicast groups. The system also includes a MID processor which traverses the at least one compound MID and resolves it into its associated simple MIDs. Accordingly, the present invention provides for a system and method for efficiently controlling multicast transmissions when different types of multicast groups are to receive the multicast transmissions. In this system and method a new type of multicast identifier (MID) is provided, a compound MID. The compound MID is a single MID but references multiple MIDs.

Abstract: A multi-terminal electrical differential line protection system wherein each of the terminals had a receiver and a transmitter and the receiver of each terminal is connected to the transmitter of an adjacent terminal to provide a unidirectional data communications link between all of the terminals in a ring on which communications between all of the terminals is in a first direction. Each of the terminals may also have an additional receiver and a transmitter and the additional receiver of each terminal is connected to the additional transmitter of an adjacent terminal to provide a unidirectional data communications link between all of the terminals on another ring on which the direction of communication is opposite the first direction.

Abstract: The present invention comprises a method for permitting fully detailed advertising of reachability information for some addresses in a network while efficiently summarizing reachability information for other addresses. In one embodiment, the invention is implemented as part of a process used by logical nodes for advertising reachability information for members of a group of nodes represented by the logical node. The invention may be used with any network that involves the aggregation of nodes and nodal elements (such as reachability information) into logical nodes, including, without limitation, networks using the PNNI and IP protocols.

Abstract: A method and apparatus to measure multicast performance over a network is described. A data coordinator coordinated a multicast protocol test between a data sender and a plurality of data receivers. A first shortest path tree is created from an intermediate device to the plurality of data receivers. A second shortest path tree is created from the intermediate device to the data sender. A group shortest path tree is formed including the first shortest path tree and the second shortest path tree to support transmission of test packets from the data sender to the data receivers. The data coordinator receives a test report from each of the data receivers. The data coordinator prepares a loss report using the test reports.

Abstract: In a first embodiment, multi-speed concatenated packet strings are transmitted by a first node on a serial bus. To accommodate multi-speed packets, a speed signal is transmitted immediately prior to the packet. In a second embodiment, ACK-concatenation is used to allow a node to transmit a data packet immediately after transmitting an acknowledge signal on the bus. The data packet need not be related to the ACK packet. In a third embodiment, a node which receives a first data packet followed by a data end signal on a child port, concatenates a second data packet onto the first data packet during retransmission. The second data packet is also transmitted down the bus in the direction of the node which originally transmitted the first data packet.

Abstract: Bridges (10, 12, 14) are used to interconnect local area networks transparently. In the IEEE 802.1D standard for bridges, a spanning tree is built among the bridges for loop-free frame forwarding (FIG. 10). Although this approach is simple, it does not support all-pair shortest paths. A novel bridge protocol is employed that attempts to find and forward frames over alternate paths that are shorter than their corresponding tree paths on the standard spanning tree, and makes use of the standard spanning tree for default forwarding. The protocol, referred to as the Spanning Tree Alternate Routing (STAR) Bridge Protocol, is backward compatible with the IEEE 802.1D standard and has a complexity that is comparable to that of the standard and other existing protocols and further includes an ability to prioritize the forwarding of frames over at least two different paths responsive to a priority value carried by a frame to be forwarded.

Abstract: In a multicast network, a method is employed for selecting a low cost multicast conference tree subject to an end-to-end delay constraint for transmissions between any two nodes in the tree that terminate conference participants. The method employs a constrained minimum cost Steiner tree selection technique that integrates facilities costs and a delay constraint into a single objective function to be minimized as the tree is incrementally configured. The method also incorporates a unique path delay metric (delta diameter) that indicates the effect on end-to-end delay resulting from the incremental addition of a next node to the Steiner tree.

Abstract: A lookup table for searching for a longest prefix match for a key is disclosed. The lookup table provides a match for a key in a single search cycle. The number of matches stored in the lookup table is maximized by storing each match in only one location in the lookup table. The binary tree is divided into a plurality of levels and each level has a plurality of subtrees. A subtree descriptor stored for a subtree includes a field for each node in the subtree. The state of the field indicates whether an entry for the node is stored in the table. The bit vector allows indexing of the single match stored for the key.