Abstract: There is disclosed, for use in a communication device, such as an access concentrator, that performs high-speed data transfers between a group of M data drivers and a group of N data receivers, a space and time division multiplexing (STDM) bus interface in which each bus line is a single source/multidrop line that connects the output of only one driver to multiple receivers (i.e., a 1:N configuration). The disclosed invention minimizes the number of data reflections on each bus line by eliminating all but one of the stubs associated with the bus drivers. The disclosed device also eliminates a single point or failure situation. The bus interface also provides additional robustness by means of a “back-up” bus line that is coupled to alternate outputs on all data drivers and to inputs on all receivers (i.e., multisource/multidrop or M:N configuration).

Abstract: A method is given for deriving a backup path routing spare capacity template that is feasible, scalable, adaptive, much faster, and near global optimal in redundancy reduction. The method includes determining working paths, aggregating the working paths into a first matrix, determining backup paths, aggregating the backup paths into a second matrix, and deriving the template from the first and second matrices. A method is also given for successively approximating the optimal spare capacity allocation needed for a network. The method includes, determining the link cost associated with a selected traffic flow's backup path, determining an updated link cost that is less than the current link cost, determining a backup path with the updated link cost, and notifying the rest of the network of the backup path.

Abstract: A method and system for protecting virtual traffic travelling through a protected domain having of a bridge node connected to a selector node in working and protection paths. Upon detecting failure of the traffic channels in the working path, the detecting node transmits failure information to the selector node along the traffic channels and along an alarm channel in the working path. The selector node initiates protection switching of the traffic channels as soon as failure information is received along the alarm channel. The alarm channel has a sufficiently high priority relative to the traffic channels that protection switching is initiated before failure information is received along the traffic channels. Thus, the selector node can initiate protection switching before receiving alarm cells on traffic channels, which significantly reduces the time during which the traffic channels contain alarm cells. Advantageously, the invention helps prevent premature termination of the end-to-end traffic connection.

Abstract: The invention relates to a method of protecting a data link (1-10, 1-20) established via an access point (GGSN1, GGSN2, ROUTER1, ROUTER2) to a mobile subscriber node (MN). The invention further includes the steps in which: (i) a monitoring network element (HA) observes the operation of the data link (1-10, 1-20); and (ii) in case the operation of the data link (1-10, 1-20) becomes unsuitable for communication, the monitoring network element (HA) starts to set up an alternative data link (1-10, 1-20) via an alternative access point (GGSN1, GGSN2, ROUTER1, ROUTER2).

Abstract: A router in accordance with the principles of the present invention employs explicit routing protocols to establish a plurality of explicitly routed label switched paths between source and sink routers. The sink router selects one of these explicitly routed paths as a primary path and communicates along that path. Upon a failure in a path selected as a primary path, a secondary path is instantaneously selected as the new primary path. Since the new route has already been established, there is no need to re-compute the path at the time of a failure. Consequently, a new path is rapidly established in response to the failure of a path. One of the new routers may employ physical level maintenance information, such as loss of signal (LOS) or loss of pointer (LOP), for example, to detect such path failures. Additionally, the new router may employ provisioned flow information to propagate path failure alarms.

Abstract: An Ethernet protection system includes an Ethernet communication device operable to be connected to first and second Ethernet lines forming a parallel connection. The Ethernet communication device is able to select the first Ethernet line and transmit and receive data over the first Ethernet line, and upon detecting a failure in the first Ethernet line, automatically select the second Ethernet line and transmit and receive data over the second Ethernet line.

Abstract: A method and system for effectuating network routing over primary and backup channels. In one embodiment, a primary link is enabled to transfer customer traffic between network nodes, while a transmission quality of the link is monitored. Upon determining the primary link has entered a marginal state, the primary link is disabled such that the network immediately determines it is unavailable. Test traffic is sent over the primary link while monitoring the transmission quality to determine if the link returns to a non-marginal state, and in response thereto the primary link is re-enabled such that the network immediately determines it is available for routing customer traffic again. In one embodiment, rerouting the customer traffic is effectuated by opening and closing the primary link, such that it appears to the network to be disconnected and reconnected. In one embodiment, the primary link comprises a free space optical (FSO) link.

Abstract: In a method of providing protection switching in a meshed communications network, a protection path between two nodes on the network is only established, on demand, as it is required, after a fault along a working path between the two nodes has been detected. After the protection path is established, carriage of traffic from the working path is switched to the protection path. Once the working path is restored, traffic is switched back from the protection path to the working path, and the protection path is torn down. Switching between working and protection channels may be effected using a path establishment protocol or using protection switching mechanisms of existing network protocols, such as SONET or ATM APS. Software and network nodes embodying the method are also disclosed.

Abstract: A multi-channel network is disclosed in which channels can be designated as “active” or “inactive” and changes can be made from one channel to another based on a metric which is a function of various channel parameters such as throughput and stability. In one form, the metric is a linear combination of factors such as the mean of the round trip time sequence of previous packets (indicating throughput) and the sample variance of the sequence of retransmission timeout values computed for previous transmission attempts (indicating stability). Regardless of the specific form of the metric or the estimation procedures for the channel parameters, these factors are combined using user-specified weights which permit the user to emphasize the relative importance of individual factors, thereby characterizing the strategy whereby “active” or “inactive” paths are used.

Abstract: A back-up channel line card-installed ESF framing mechanism independently sources an FDL signaling channel for the transport of protection switch signaling information, taking advantage of the fact that DSL multiplexer equipment is capable of accepting and processing ESF framed digital data, including embedded FDL-based signaling information. Upon completion of transport of the FDL-based signaling information, the back-up channel is used for data transport in place of a faulty channel.

Abstract: A method, architecture and service of providing a multiple tiered pricing structure for providing a first service level to priority traffic where the priority traffic is protected via a 1:1 protection system, and a second service level for non-priority or extra traffic, wherein the extra traffic is normally propagated via the protection path, and is protected using a mesh restoration technique in the event of failure of the protection path or use of the protection path by the priority traffic.

Abstract: A system operating on a communication network for mapping service-level information comprising logical connections to physical-level information comprising working physical paths of the logical connections, where the physical-level information is obscured by activation of protect schemes within the communication network.

Abstract: Methods and systems for providing redundant network connectivity across a network using a tunneling protocol by dynamically moving a TLS tunnel between master and slave switches based on relative connectivity provided by the switches are disclosed. A standby routing protocol executes on the master and slave switches to monitor the relative connectivity. In response to detecting that the relative connectivity of the slave switch exceeds that of the master switch, the standby routing protocol reverses the roles of the master and slave switches, thus moving the TLS tunnel to the new master switch.

Abstract: In a method and a device for redundant transmission of protection commands between remote tripping devices (1, 8), useful information which represents a protection command or a rest signal is transmitted by a first remote tripping device (1) in at least two time slots via a first interface (2) to a first multiplexer (3), and is transmitted via different transmission paths (4, 5) by the multiplexer (3) based on the time slots. A second multiplexer (6) receives the useful information via the different transmission paths (4, 5), and transmits each useful information item via a time slot, which is allocated to the respective transmission path (4, 5), in a second interface (7) to a second remote tripping device (8).

Abstract: A method and apparatus for switching messages from a primary message channel to a secondary message channel in a message queuing system in which messages are placed in a first transmission queue of a local system for transmission to a remote system via a primary message channel. A local queue manager continuously checks to see whether a high water mark has been reached in the first transmission queue, indicating an apparent failure in the primary message channel. On determining such an apparent failure in the primary message channel, the queue manager determines whether the secondary message channel is associated with the first transmission queue. If so, the queue manager activates the secondary message channel to serve said first transmission queue. If, on the other hand, the secondary message channel is associated with another transmission queue, the queue manager transfers messages already in the first queue to the other queue and redirects any new messages intended for the first queue to the other queue.

Abstract: In a routing control method in a network supported by a shared restoration system, link data associated with nodes in the network are received and transmitted. The link data contains data of sharable backup band. The received link data is managed as a link data management table. The link data further contains data of an unreserved band for each of links associated with each of the nodes. Also, the sharable backup band data is managed for every share risk group. In this case, the sharable backup band data for the share risk group of a maximum bandwidth may be transmitted to at least a part of the nodes.

Abstract: A node of #B selects an ISDN line for backup in which a bulk transfer by a plurality of B channels is performed, out of a plurality of ISDN lines which can be set by a node of #A, by way of the pilot selection function on the ISDN switching network side. At this time, two nodes of #A and #B exchange both the child number of an ISDN line to be selected and the number of B channels to be transferred in bulk as user-user information in the D channel message of the ISDN line with each other, and select an ISDN line based on the information.

Abstract: A hitless switching system includes a sending apparatus and a receiving apparatus. The sending apparatus includes: a distributing part for dividing an original signal into a plurality of signals; and a transmitting part for transmitting the divided signals over one or a plurality of transmission lines with redundancy. The receiving apparatus includes: a phase difference detection part for detecting phase differences between signals sent from the sending apparatus; a phase difference absorbing part for absorbing phase differences detected by the phase difference detection part; selectors each of which selects one signal from a plurality of signals; and a restoring part for restoring the original signal from the signals output from the selectors.

Abstract: A multiplexer capable of automatically and dynamically selecting a correct or the best input out of a pre-configurable set of alternative inputs, based on the current status of the alternative inputs. An input status-sensitive, dynamic, M-by-M digital cross-connect can be formed out of an arrangement of M (an integer) instances of such input-controllable dynamic M:1 multiplexers. An application is an SDH/SONET cross-connect system that is able to perform a protection-switch for any number, up to all, of its output paths, simultaneously, if necessary, thereby enabling a short and deterministic latency for individual-path-granular protection-switch process for cross-connects of unlimited capacity. Another application is an SDH/SONET path that can be dynamically shared, even at a single time-slot granularity, among multiple path sources.

Abstract: A method for sharing a backup path in a MultiProtocol Label Switching (MPLS) network, a label switching router (LSR) for setting a backup path in an MPLS network, a system for setting a backup path in an MPLS network, and a recording medium therefor are provided. The method includes the steps of acquiring link configuration information of links included in a working path when the working path is set between a source node and a destination node, and allocating bands for a backup path using the link configuration information when the backup path is set between the source node and the destination node. In the method, an optimal band is allocated to each of links included in a backup path by calculating a band using information, which is obtained during setting of a working path, about at least one other working path sharing links with the working path when the backup path is set, thereby efficiently managing network resources without wasting them.

Abstract: To provide a label switching network in which the network resources and the operation cost can be reduced, and the scalability problem to a large scale network can be solved.

Abstract: A system and method for managing communication links connecting components in a network element is provided. The network element has a first component, a second component and at least two communication links. The communication links are adapted to provide a first connection and a second connection between the first component and the second component. The system includes, for each communication link of the at least two communication links connected to the first component and adapted to provide the first connection and the second connection, a detection module adapted to monitor a given communication link for an error. The system also includes, for each communication link connected to the second component and adapted to provide the first connection and the second connection, another detection module adapted to monitor another given communication link for an error.

Abstract: A stackable network unit comprises a ‘down’ port and an ‘up’ port, an arbitration path for data packets from the down port to the up port, a repeat path for data packets from the up port to the down port, a link detector for detecting tile absence of another operative unit connected to the down port to cause data packets on the return pat to bypass the down port and proceed on the arbitration path and for detecting the absence of another operative unit connected to the up port to cause data packets on the arbitration path to bypass the up port and proceed on the repeat path.

Abstract: The present invention concerns a communication node accommodating terminals for various kinds of media, and more particularly the invention provides an intranode alternate route generation method and apparatus for generating an alternate route as needed within the node when a failure or congestion occurs in line control equipment in a line accommodating section of the node.

Abstract: A method for providing automatic restoration of network access for user lines within a communication system. The user lines interface with groups of transmission lines that include dedicated transmission lines which are connected to the user lines, idle transmission lines and reserved transmission lines. The method includes steps for making a number of transmission lines among the groups of transmission lines available for user lines which have a dedicated transmission line in a group of transmission lines that fails and for coupling each of such user lines to a respective available transmission line. The method may also include steps for delaying the coupling of such user lines if a sufficient number of transmission lines are not available.

Abstract: A two-way communication system that can shorten the system recovery time when a link switching operation between a center station and a relay station occurs over two-way CATV networks, passive optical star networks and the like. A center station measures the round-trip propagation delay of a signal when a subscriber station starts its operation and then sets the transmission delay of the subscriber station so as to equalize the round-trip propagation delay to a fixed system delay. When a link switching operation occurs from a working system to a standby system, the center station measures the round-trip propagation delay of a signal for a subscriber station after the link switching operation and then resets transmission delays of all subscriber stations connected to the relay station to a time based on the difference between the measured delay and the round-trip propagation delay of a signal before the link switching operation.

Abstract: Disclosed is a method and apparatus for providing fault tolerance in Totem Networks by use of redundant fabrics. The above is accomplished in one embodiment of the invention by operating devices on the network in such a way that the devices mark the token to indicate when the token has been switched from one fabric to another in response to a timeout. A Ring Master device on the network determines, based on switching of the token by devices on the network whether a fabric or device on a fabric of the network has failed. In addition, fabrics that have failed are monitored to determine when they have become operational. Retransmission of improperly received messages as per token-message-order protocols are also provided for situations in which the token is received before all messages intended for a given device have been properly received.

Abstract: A method for distributed managing of restoration paths within a communication network having nodes connected by links; comprising the steps of: (a) establishing a spare link catalog identifying unassigned links connecting each selected node with an adjacent node; (b) sending a probe message from each node to each adjacent node over an unassigned link; (c) evaluating the probe message at each adjacent node according to predetermined criteria; (d) forwarding the probe message to subsequent adjacent nodes, or discarding the probe message, as determined by the evaluating; (e) appending message content to the probe message indicating the path sequence traversed by the probe message proceeding through the network; (f) evaluating the forwarded probe message at each said subsequent node according to the predetermined criteria; (g) repeating steps (d) through (f) for each forwarded probe message until it is discarded or is received by the probe message originating node; (h) the probe message originating node noting ea

Abstract: In prior art, equivalent switching of MPLS packets can result in maloperations. The inventive method provides a solution to the problem in the following manner: when a working entity fails, equivalent switching is controlled in accordance with priority criteria and logical link information for one single protection entity.

Abstract: A SONET format signal transport system and method providing an increased transport capacity. The transport system includes multiple low speed transport systems wherein each low speed transport system can have a pair of low speed terminals connected by N working channels and one protection channel. A clear channel high speed SONET transport system is connected between the low speed transport systems. The clear channel high speed SONET transport system has N+1 working channels that each terminate at a high speed terminal. The low speed system protection channels are multiplexed into a protection channel of the clear channel high speed system, while each working channel of each individual low speed system is multiplexed into different high speed channels.

Abstract: The preferred embodiment of the present invention is a cable modem apparatus for reliably providing a personal computer access to the Internet through a cable television link and a public switched telephone network link. The invention includes: a cable television link failure detector connected to the cable television link; a message generator connected to the cable television link failure detector, where the message generator is configured to generate at least one message responsive to the cable television link failure detector; and a message transmitter connected to the message generator, where the message transmitter is configured to transmit the at least one message through the public switched telephone network link to cause Internet communications to be communicated to the personal computer through the public switch telephone network link.

Abstract: A system and method are disclosed for processing digital signals in a telecommunications system that allow for hit-less switching between a first digital signal in which a first payload, a first pointer value, and a first frame are transported on a first channel, and a second digital signal in which a second payload identical to the first payload, a second pointer value, and a second frame are transported on a second channel. The present invention includes first and second pointer followers, first and second comparators, a delay buffer with control circuit, first, second, third and fourth multiplexers, and a pointer generator. The delay buffer control circuit further comprises a write counter, a read counter, a phase detector, and a leak-out mechanism for reinitializing the delay buffer. The present invention aligns the payloads of the first and second digital signals to allow for hit-less selection between them.

Abstract: An Ethernet protection system includes an Ethernet communication device operable to be connected to first and second Ethernet lines forming a parallel connection. The Ethernet communication device is able to select the first Ethernet line and transmit and receive data over the first Ethernet line, and upon detecting a failure in the first Ethernet line, automatically select the second Ethernet line and transmit and receive data over the second Ethernet line.

Abstract: An optical receiver unit is connected to each of a work optical line and a protection optical line, and after an optical signal is converted to an electrical signal, only the overhead of the signal is extracted. Furthermore, bytes accommodated in the overhead are demultiplexed. K bytes are transferred to both an APS processing unit and a mismatching judgement unit. The mismatching judging unit judges whether or not a WTR, DNR, RR, etc. are set in the K1 byte received from the opposite station, compares the mode of the opposite station with the mode of its own station, and detects a mismatching between the modes of the opposite and own stations. The result of the detection is transferred to the APS processing unit, and if there is a mismatching, the mismatching is solved.

Abstract: A multiple endpoint path for providing endpoint redundancy is described. Selected active end nodes in a digital communications network are configured by a network management system to have compatible alternate endpoint paths. When one of the selected active endpoint paths fails, the network management system automatically switches the endpath from the previously active endpoint to the alternate end point path.

Abstract: A digital broadcast program broadcast with a first network is transmitted to a second network. A tuner 41 selects digital broadcast signal having a predetermined transmission frequency and ECC decoder 43 obtains MPEG2 TS packet S3 as the digital broadcast data on the digital satellite broadcasting. An NIT detecting circuit 44 detects NIT from the MPEG2 TS packet S3 and a control unit 31 changes the NIT to obtain a table NITb applicable to CATV. A NIT substitution circuit 48 detects NIT from the MPEG2 TS packet S3 and substitutes table the NITb for the NIT to obtain MPEG2 TS packet S4 as the digital broadcast data on the CATV. Then, an error correct code is added to the MPEG2 TS packet S4 and the added packet S4 is modulated. Then, modulated one is frequency-converted to obtain digital broadcast signal BS-1 having a predetermined transmission frequency for the CATV.

Abstract: A routing mechanism, service or system operable in a distributed networking environment. One preferred environment is a content delivery network (CDN) wherein the present invention provides improved connectivity back to an origin server, especially for HTTP traffic. In a CDN, edge servers are typically organized into regions, with each region comprising a set of content servers that preferably operate in a peer-to-peer manner and share data across a common backbone such as a local area network (LAN). The inventive routing technique enables an edge server operating within a given CDN region to retrieve content (cacheable, non-cacheable and the like) from an origin server more efficiently by selectively routing through the CDN's own nodes, thereby avoiding network congestion and hot spots.

Abstract: A method and system is provided for in-order delivery of frames in Fibre Channel communication networks during topology change. When a topology change has rendered an old path between two switches or end devices infeasible, a new path is determined to replace the old path. To ensure in-order delivery of frames, the new path is activated only after the lapse of a hold-down period. The hold-down period may be calculated as the maximum time required for frames within the old path immediately prior to the topology change to reach the destination switch or device. The calculation may utilize information available from the Fibre Channel shortest path first (FSPF) protocol.

Abstract: A method of restoring data transport following a network resource failure in a communication network includes searching for protection bandwidth in a data transport ring where the transport resource failure occurred, and the search is extended to protection bandwidth on adjacent data transport rings, as required, until protection bandwidth for restoring data transport are located or all adjacent rings have been searched. Thus the ratio of working:protection bandwidth is improved by elimination of protection bandwidth between matched pair nodes interconnecting adjoining BLSRs of the network. However, high reliability which is characteristic of a BLSR network is preserved by providing a recovery algorithm that promptly allocates protection bandwidth of one or more rings, as required, in order to circumvent a failed network resource.

Abstract: Link failure messages are sent through a network to accelerate convergence of routing information after a network fault. The link failure messages reduce the oscillations in routing information stored by routers, which otherwise can cause significant problems, including intermittent loss of network connectivity as well as increased packet loss and latency. For example, the link failure messages reduce the time that a network using a path vector routing protocol, such as the Border Gateway Protocol (BGP), takes to converge to a stable state. More particularly, upon detecting a network fault, a router generates link failure information to identify the specific link that has failed. In some types of systems, the router communicates the link failure information to neighboring routers as well as a conventional update message withdrawing any unavailable routes. Once other routers receive the link failure information, the routers do not attempt to use routes that include the failed link.

Abstract: In a communication network having a plurality of terminals, such as packet forwarding apparatus, and a transport network which provides a connection between the terminals, when the transport network performs a state transition associated with a brief disconnection, a brief disconnection begin notification signal is sent to a terminal prior to a state transition operation and a brief disconnection end notification signal is sent to the terminal after the state transition operation. The terminal reroutes communication data to a storage or a redundant transport route during the period between the receipt of the brief disconnection begin notification and the receipt of the brief disconnection end notification. Accordingly, the communication data loss due to the brief disconnection between terminals associated with the state transition of the transport network can be reduced or eliminated.

Abstract: A method and apparatus that carry out communication between a customer premises equipment and a target network service through any of a number of head ends. When a connectivity between the customer premises equipment and the target network through a first head end is lost, a call is initiated to a server using an Internet protocol network. A second, alternate, head end is selected based on the customer premises equipment, the first head end, the target network, the network service, the day and the hour. Subsequently, the customer premises equipment is coupled through the second head end to the target network.

Abstract: A Method for restoring traffic in a network. The network includes plural distinct nodes interconnected by plural distinct spans, each span having working links and spare links. Each node has a digital cross-connect switch for making and breaking connections between adjacent spans forming span pairs at a node. Cross-connections between spare links in adjacent spans are made such that sets of successive nodes through which the adjacent spans form span paths form closed paths. A method of finding and construction closed paths is described in which statelets are broadcast through the network. In a preferred method of implementation of the method, the statelet broadcast occurs not in response to a network failure, but across the entire network before any particular span failure and may be carried out during normal network operations as a continual re-configuration of the network.

Abstract: To ensure the integrity of a telecommunications network provisioned with a distributed restoration algorithm (DRA), a communications network is provided for routing signaling messages such as DRA restoration and maintenance messages among the various nodes of the network. Thus, while data is sent among the nodes via the working links interconnecting the various nodes, signal messages are communicated among the various nodes by way of the independent communications network, which may be a wide area network. By reallocating the signal messages to a separate network, an efficient telecommunications network is effected.

Abstract: A method of timing an attempt to establish a connection path between a first and second node in a communications network is provided. The method initiates the attempt to establish a connection path after a period of time has elapsed wherein the period of time is greater than another period of time which had previously elapsed between two previous attempts, if any, to establish the connection.

Abstract: Tis invention provides a ‘capacity slice’ nodal switching device (in the ADM-like sense) that is designed for deployment under the p-cycle concept. The device's key architectural properties are access, east and west interfaces, with one spare and working port, on each of these interface sides, plus at least two straddling side interfaces. The straddling side interfaces each have equal line capacity to those of east and west interfaces, but all are usable for working capacity. In application, the plug cards in the nodal switching device are supplied to provide up to two line signal units on the straddling side of the p-cycle device, per diverse span arriving at the site. Network level deployment and configuration of the devices requires that they be arranged in p-cycles.

Abstract: A packet network of interconnected nodes employs dynamic backup routing of a Network Tunnel Path (NTP) allocates an active and backup path to the NTP based upon detection of a network failure. Dynamic backup routing employs local restoration to determine the allocation of, and, in operation, to switch between, a primary (also termed active) path and a secondary (also termed backup) path. Switching from the active path is based on a backup path determined with iterative shortest-path computations with link weights assigned based on the cost of using a link to backup a given link. Costs may be assigned based on single-link failure or single element (node or link) failure. Link weights are derived by assigning usage costs to links for inclusion in a backup path, and minimizing the costs with respect to a predefined criterion. For single-link failure, each link in the active path has a corresponding disjoint link in the backup path.

Abstract: A transmission line duplexing processing method comprises the steps of installing duplex transmission line between a plurality of terminal devices, the duplex transmission line being duplicated by first and second transmission lines, making it possible to send and receive data of a stream unit train between the terminal devices by using a TCP protocol, sending the data of the stream unit train simultaneously to the transmission lines, receiving data, and handling only data which is included in the data sent at the sending step and which has arrived earlier, as received data, detecting an abnormality caused on either of the first and second transmission lines, and responding to detection of occurrence of the abnormality on the transmission line conducted at the abnormality detecting step, to close the transmission line having the abnormality and conduct sending and receiving by using a remaining normal transmission line.

Abstract: A distributed method for creating telecommunications paths in a network, particularly after a span failure. The network includes plural distinct nodes interconnected by plural distinct spans, each span having working links and spare links. Each node has a digital cross-connect switch for making and breaking connections between adjacent spans forming span pairs at a node. At least one of the end nodes of a path to be created broadcasts statelets. Each intermediate node between the end nodes broadcasts incoming statelets in a manner that favours use of restoration paths that eliminate the fewest other paths. Statelets that have traversed spans with greater spare capacity, considering the number of statelets competing to be broadcast along the spans, are preferentially broadcast.

Abstract: A switch is provided for use in a communications system for transmitting traffic from a first user to a second user. The first and the second users are interconnected by a primary communications path and a redundant communications path. The switch includes a first port configured to receive hello communications indicative of a proper operation of the primary communications path and a second port for receiving data communications. A switch control monitors the receipt of the hello communications, directs the forwarding of received data communications up to a threshold capacity and, if the received data communications exceed the threshold capacity, drops at least a portion of the received data communications such that forwarded data communications are below the threshold capacity.