Abstract: A node apparatus in a ring network in which a protection path is provided that cycles around the ring network and transports a signal in a direction opposite to a signal transporting direction of the working path and in the event of a failure of the working path, a node apparatus adjacent to the failure loops back the signal flowing on the working path onto the protection path, the node apparatus comprising: allowable bandwidth storing unit which stores a maximum total bandwidth value, which represents the largest value among per-link total values of bandwidths that a plurality of working paths use on respective links connecting between the node apparatuses, as an allowable bandwidth for a shared path; and bandwidth control unit which controls the bandwidth of traffic flowing on the protection path, in accordance with the allowable bandwidth.

Abstract: The present invention discloses a method for controlling a physical bandwidth of a ring-based network by employing a ring application of a data link layer that operates in a physical layer. The method includes the steps of a) requesting each of a plurality of node apparatuses included in the ring-based network to confirm whether the bandwidth can be changed, b) instructing each node of the apparatuses to prepare for the bandwidth change upon receiving a confirmation that the bandwidth can be changed, c) reporting that the preparation for the bandwidth change is completed, and d) changing the bandwidth by using a bandwidth changing function of the ring application upon receiving the report of the completion of the preparation for the bandwidth change.

Abstract: A method that changes the selection of a 2:1 multiplexer that receives a first output signal from a first framer and a second output signal from a second framer. The first output signal is the same as the second output signal. An apparatus having a framer and a 2:1 multiplexer that receives an inbound signal from the framer. A first multiplexer receives at least one signal from another framer and the 2:1 multiplexer has an input coupled to an output from the first multiplexer. A second multiplexer receives at least one signal from the other framer and the second multiplexer has an output coupled to an input of the framer for an outbound signal.

Abstract: An optical ring network has one or more working wavelengths and multiple protection wavelengths adapted to support the working wavelength(s). Routing tables may be used in network nodes to assign traffic of a failed working wavelength to a protection wavelength. The protection technique may be applied to networks employing, for example, Dense Wave Division Multiplexing (DWDM).

Abstract: Extra traffic paths are provided in a communication network including at least two protection channels associated to respective transmission channels. Each protection channel admits an active state for carrying, in the presence of a failure in the associated transmission channel, traffic to be carried by the associated transmission channel, and a stand-by state, wherein the protection channel is adapted to carry extra traffic. The protection channels are run in a sub-network connection protection scheme, whereby one of the protection channels in its stand-by state is adapted to ensure recovery of extra traffic carried by the other protection channel while the other protection channel is switched to its active state or is subject to failure.

Abstract: A method of automatically provisioning a network-wide function using a plurality of network elements in a service provider network and using a sub-network level approach is provided. In one specific approach, a software wizard facilitates provisioning a bi-directional line switched ring (BLSR). First user input, specifying a plurality of ring attribute values that define attributes of a bi-directional line switched ring, is received. Second user input, specifying one or more working spans for the bi-directional line switched ring, is received. Each of the network elements is automatically configured to participate in the bi-directional line switched ring based on the parameter values. Embodiments may provide a software wizard for implementing the foregoing process.

Abstract: Provided is an operational status testing apparatus and method for an Ethernet-based APS process. A test command signal which contains a command to perform an operational test for the APS process of a first node and a second test response signal that indicates that the operation of the APS process of a second node is performed normally, from among far end request signals that are received from the second node connected to own first node via an Ethernet network, are filtered.

Abstract: A node within a network comprising a transport layer protocol for multicasting datagrams on a virtual ring. Each node on the virtual ring is logically connected to two neighbour nodes through virtual connections. A virtual ring datagram is sent to a downstream neighbour node on the virtual ring and a token is received. The virtual ring is identified and the token is forwarded to the downstream neighbour node. If the received datagram is a virtual ring datagram, the virtual ring is identified and the node originator of the received virtual ring datagram is checked. If the received virtual ring datagram has not been locally originated, data in the virtual ring datagram is processed and the virtual ring datagram is forwarded to the downstream neighbour node on the virtual ring. If the received virtual ring datagram has been locally originated, the virtual ring datagram is removed from the virtual ring.

Abstract: A network includes a plurality of redundant nodes and ordinary nodes. A first redundant node from among the redundant nodes sets a common address and setting information in a message packet and broadcasts the message packet over the network. The common address is commonly used by all the redundant nodes on the network. The setting information is indicative of the fact that the first redundant node is a redundant node. All the nodes have a topology table. The nodes that receive the message packet set in their topology table information indicating of presence of the first redundant node and the common address shared by the redundant nodes. When transmitting a packet to the first redundant node, a node sets the common address as a destination address of the packet.

Abstract: The synchronization of trunk failover between two FC-AL switches when a primary trunk failure occurs is disclosed. If primary trunk T1 should fail, S1 bypasses the cascade port and sends a MaRK (MRK) ordered set out over duplicate trunk T2 to switch S2. In response, S2 sends an acknowledgement MRK ordered set over T2 back to S1. S1 then reconfigures the switch to establish T2 as the primary trunk, and acts as a masters in the failover process and initiates LIP ordered sets which are communicated to all devices in the system to initialize them. Note that when S2 receives the MRK ordered set and acknowledges it by sending an acknowledgement MRK back to S1, it acts as a slave in the failover process and does not attempt to initiate LIPs, thereby eliminating the possibility of multiple Loop Initialization cycles and reducing the time in which data cannot be transmitted.

Abstract: Network traffic is sent via alternate paths in cases of network link or node failure. An alternate node responds to U-Turn traffic from a primary neighbor to select a further alternate. An algorithm for determining the alternate paths is provided to select loop-free neighbors.

Abstract: A cellular communications network architecture is disclosed. The architecture includes a mobile switching office, a first base transceiver station in communication with the mobile switching office via a first communications link, and a second base transceiver station in communication with the mobile switching office via a second communications link. A first optical switch is in communication with the first base transceiver station via a third communications link and a second optical switch is in communication with the second base transceiver station via a fourth communications link. A fiber optic communications link couples the first optical switch with the second optical switch. The first optical switch is physically located separate from the first base transceiver station and the second optical switch is physically located separate from the second base transceiver station.

Abstract: Methods and apparatus for processing a failure and a subsequent recovery in a ten Gigabit Ethernet (GE) optical transport network (OTN) wave division multiplexing (WDM) ring are disclosed. According to one aspect of the present invention, a device includes a plurality of ports, a sensing arrangement, and a processing arrangement. The ports include a first port that is initially configured to be in a forwarding state, and the sensing arrangement identifies whether the first port is facing or interfaced with a failure associated with the network ring. The processing arrangement being generates at least a first G.709 frame, and inserts at least one bit into the first G.709 frame that indicates that the failure associated with the network ring has been identified if the first port is facing a failure. The processing arrangement forwards the first G.709 frame through the second port.

Abstract: The present invention discloses a protection switching apparatus for nodes in a Resilient Packet Ring (RPR) network, including: a first switching module, for receiving inner ringlet data and transmitting data to the outer ringlet; a second switching module, for receiving outer ringlet data and transmitting data to the inner ringlet; and when it is in a normal mode, each of the switching modules transmits the received ringlet data to the other switching module connected to itself, and the received ringlet data are transmitted through normal data paths; when protection switching is required and frame boundaries of data are reached, the first and second switching modules directly switch data paths within themselves, and transmit the received ringlet data through WRAP data paths. At the same time, a protection switching method for nodes in an RPR network is provided.

Abstract: Methods and systems for identifying communication circuits are disclosed. In particular a communication circuit communicatively couples a first node to a second node. A virtual circuit identification is then obtained based on a first address associated with the first node and a second address associated with the second node. The communication circuit is then identified based on the virtual circuit identification.

Abstract: A ring network protection method for an optical transmission network relates to digital information transmission, and includes using the overhead byte APS/PCC in the ODUk to transmit the protection information of the APS. The method adds fields in the APS/PCC and further includes: (a) the network element in which the protection switching takes place in the OTN sends the protection switching information to other network elements through the fields set in the APS/PCC of the ODUk; and the network element which received the ODUk performs corresponding processing according to the fields carried by the APS/PCC in the ODUk and implements the protection switching for the OTN ring network.

Abstract: A loop detection system and method operable in an Ethernet network having a provider network and a customer network. In one embodiment, a provider edge (PE) entity is operable to generate a test frame with at least one of a destination address (DA) and source address (SA) that is unknown to the customer network. The test frame is broadcast to the customer network coupled to the PE entity. Upon determining that the test frame or its duplicates are received back by the PE entity within a first time period, loop location within the Network is deduced responsive to the determination.

Abstract: Embodiments of the present invention provide a method and a node for discovering topology structure automatically in a Multi Protocol Label Switching (MPLS) ring network. The method includes: when receiving a topology discovering message, determining, by a node in the MPLS ring network, whether the topology discovering message is sent by the node; if yes, updating information of topology structure of the MPLS ring network stored in the node according to information of topology structure of the MPLS ring network carried by the topology discovering message; otherwise, appending information of topology structure of the node to the topology discovering message and forwarding the topology discovering message to a next node. Thus, the network topology may not depend on the topology of the physical layer network and the speed of discovering topology structure of the ring network is increased.

Abstract: To restore a failed working path (WP) in a transport network, a restoration request is relayed between adjacent network elements (NE1, NE2) and the path set up hop by hop over spare resources by establishing local crossconnections (CC1, CC2) conforming to the request according to routing information locally stored within the network elements. During failure free operation, a low priority path (LPP A) for extra traffic with different signal structure is allowed on the spare resources and pre-empted in the case of a failure. The restoration request is forwarded using the old signal structure of the extra traffic path. Only after reception of a confirmation sent back by the peering node (NE2) using the new signal structure, the I/O port (211) is also reconfigured to the new signal structure.

Abstract: One embodiment in accordance with the invention is a method that includes detecting a failure in a ring network and transmitting a multicast message across the ring network that includes information regarding the failure. Additionally, a new ring master of the ring network is designated. Furthermore, a ring port coupled to the failure is blocked.

Abstract: In one embodiment, a method includes receiving a multicast join message at a node having a plurality of interfaces, identifying the interface at which the join message was received, and selecting one or more of the interfaces to transmit the join message based on whether the join message was received on a ring interface. If the join message was received on one of the ring interfaces, the join message is transmitted on another of the interfaces. If the join message was not received on one of the ring interfaces, the join message is transmitted on both of the ring interfaces. The method further includes receiving multicast data and transmitting the multicast data on the interface at which the join message was received.

Abstract: The present invention provides a data transfer network receiving a higher evaluation overall than conventional ones from various perspectives such as the number of effective nodes, the required number of links, and the required maximum node capacity. The present invention is a data transfer network of a hyper configuration in which each node is an element of m (m is 2 or more) different local networks. Further, at least one of the local networks to which the respective nodes belong is a hub network and, when a node belongs to a local network other than a hub network, the local network is a full mesh network.

Abstract: A bi-directional line switched mesh includes at least one bi-directional line switched ring (BLSR) sharing a common section with a partial bi-directional line switched ring (PBLSR). The partial bi-directional line switched ring has no working traffic along the common section, but may utilize the protection bandwidth associated with the common section of the BLSR in the event of a span failure of the PBLSR. Both electrical and optical PBLSR networks are also disclosed including methods of operating the asymmetrical ring nodes having unconfigured working ports (spans).

Abstract: A method and apparatus for load balancing and protecting data traffic in an optical ring is described. A method comprises configuring multiple spanning trees in a set of one or more network elements of an optical ring, load balancing with the multiple spanning trees data traffic transmitted in unprotected data channels provisioned through the optical ring, and protecting the unprotected data channels with the multiple spanning trees.

Abstract: The invention relates to a method for operating a network as well as a network comprising at least one switch (400) and network infrastructure devices that are connected to said at least one switch (400) which is controlled by a control unit (700). According to the invention, a redundant unit (550) that is connected between the switch (400) and the control unit (700) analyzes the data stream between the switch (400) and the control unit (700), and data is inserted into and/or is removed from the data stream in accordance with the result of the analysis.

Abstract: Packet-aware transport architecture and techniques for implementing same that enhance data volume by scaling effectively to rapid data growth are disclosed. For example, a technique for determining a route for a demand in a circuit-switched network comprises the following steps/operations. The demand to be routed in the circuit-switched network is obtained. The circuit-switched networks implements a packet ring (PR) model such that one or more demands are routable on one or more virtual data rings in the circuit-switched network. An Ethernet-Over-SONET (EOS) communication channel in the circuit-switched network suitable for accommodating the demand is specified. The EOS communication channel or one of the one or more virtual data rings is then identified as the new route for the demand.

Abstract: The invention discloses a method for dynamically allocating link bandwidth on resilient packet ring. This algorithm comprises the steps of measuring a group of variables in one advertisement interval, calculating the local fair rate using the measured variables, determining an advertising rate based on the local fair rate, and transmitting the data packets with the advertising rate. Compared with existing fairness algorithms, the new algorithm introduces integration for the idle rate to achieve 100% of bandwidth utilization. It also avoids using the concept of “congestion state” which is essential in the existing fairness algorithm.

Abstract: An ADM apparatus includes a first synchronism section for detecting synchronism when a reception frame received from a reception port is a first frame, a fault information detection section for detecting whether or not fault information is set in a first predetermined region of an overhead of the first frame and outputting a signal representative of whether or not the fault information is set, a second synchronism section for detecting synchronism when the reception frame is a second frame, a third synchronism section for detecting synchronism when the reception frame is a third frame accommodated in the second frame, and an inhibit section for invalidating the output signal of the fault information detection section if, when the synchronism is detected by the first and second synchronism sections, synchronism is detected with regard to the preceding frame by the second synchronism section.

Abstract: A building control or danger warning system includes a two-core circular bus for voltage supply and for communication with bus user circuits connected to the cores of the circular bus. The bus user circuits are looped-into the circular bus via FET (field effect transistor) polarity-reversal protection bridges, thereby simplifying connection of the bus user circuits to the circular bus. A bus user circuit is located between d.c. connection terminals and connected in parallel with two protection bridges. The bus user circuit measures the voltage conditions and polarity of the a.c. voltage input terminals of the bridges. According to the results of the measurement, the bus is relayed to the subsequent bus user circuit.

Abstract: According to the transmission method, labels to be used at the failure occurrence are previously and individually set to links in respective directions among all nodes on the one directional link connecting between adjacent nodes basis, and when a failure occurs, a failure notifying message is sent out onto a same directional ring from a termination node of a failed block, to be sequentially transferred to each downstream node, and a label table for connecting the links in cooperative with the reception of the failure notifying message is created in each node, and also, a bypassing path is formed by turning back the rings at both end nodes of the failed block. Thus, in a ring network of label switching system, it becomes possible to easily perform the label table management and also to set a bypassing path in a short time at the failure occurrence.

Abstract: Methods and apparatus for switching Fiber Channel Arbitrated Loop Systems is provided between a plurality of Fiber Channel Loop devices. In one aspect of the invention, the system switches based at least in part on arbitrated loop primitives. An exemplary interconnect system may include a first port and a second port, both including port logic to monitor certain arbitrated loop primitives, a connectivity apparatus, a route determination apparatus including a routing table consisting of ALPA addresses and their associated ports, the route determination apparatus coupled to each port and the connectivity apparatus, where the connectivity apparatus creates paths between the ports based on arbitrated loop primitives. In one embodiment, the connectivity apparatus is a crossbar switch. Examples of the arbitrated loop primitives that cause the switch to create paths between ports includes one or more of the following: ARB, OPN and CLS.

Abstract: A method is described for enhancing a trail/path protection function in a SDH/SONET network, the network comprising a number of working resources and a number of protection resources and transmitting signal frames having a section overhead in SDH technology, or a Line OverHead in SONET technology, and a POH, said protection function comprising linear MSP N:1 trail protection function based on transmission of protection information through K1 and K2 bytes of Section OverHead in SDH or Line OverHead in SONET, wherein the method further comprises the step of mapping the content of said K1 and K2 bytes by protocol exchange into POH bytes of the path overhead in SDH or SONET, at Low Order and/or High Order level, so as to allow the handling of more than one protecting resource shared among different working resources, both in end-to-end handling and in intermediate handling.

Abstract: A method for automatic protection switching in a ring network detects a link failure at a first interface of a node, generates a first link down message and sends the first link down message along the second direction of the ring network. Upon generation or receipt of the first link down message by the redundancy manager, the redundancy manager is unblocked such that non-control frames of the at least one automatic protection switching domain are no longer blocked by the redundancy manager. Upon generation or receipt of the first link down message by one of the nodes, the node having at least one entry assigning an address to the second interface IF2, deletes only the entries in the forwarding database of the node which assign an address to the first interface of said node. Deleted entries are then updated in the forwarding database.

Abstract: The present invention discloses a method for routing in a ring network, the ring network comprising multiple connected nodes, wherein, the method includes: each node in the ring network acquiring topology information of the ring network, obtaining under-ring routings learnt by the other nodes from a under-ring network, calculating a main path and a backup path to each routing according to the acquired topology information of the ring network, creating an FRR switch table, and switching between the main path and the backup path according to the FRR switch table when a failure occurs in the ring network. Accordingly, the present invention also provides a node in the ring network. Adopting technical scheme provided by the present invention, a simple routing implementation for ring network and fast convergence when a failure occurs can be provided.

Abstract: A network element receives frames from multiple ring networks. Each ring network linked to the network element is supported by a designated support program. The received frames are monitored for conditions indicative of a failure in one of the ring networks. Upon detection of a failure condition, the designated support program for the failing ring network is determined and notified. The designated support program then addresses the failure condition by, for example, switching to a backup link. In one example, the multiple ring networks are SONET BLSR networks.

Abstract: A method for protecting Ethernet data packets transmitted over SDH/SONET traffic in a ring-like optical network formed by a number of nodes, the method includes utilizing MS-SPRING/BLSR system for SDH/SONET traffic protection and, in case of one or more network failures that result in at least one isolated node in the network, the method comprises preventing initiation of a squelching algorithm of the MS-SPRING/BLSR system with respect to the SDH/SONET virtual containers carrying the data Ethernet packets, while ensuring that the standardized use of byte J1 is prevented with respect to the same SDH/SONET virtual containers carrying the Ethernet packets.

Abstract: Embodiments of an apparatus and method for high-speed testing of a device under test are described herein, where the device under test is coupled to a tester via a limited passband communication channel. A plurality of test vector patterns is generated having characteristics such that when a given test vector pattern is transmitted electrically at a transmission rate via the communication channel, the test vector pattern has a frequency content that is less than the frequency content of a high frequency test vector pattern if the high frequency test vector pattern were to be transmitted electrically at the transmission rate via the communication channel, and such that the frequency content of each test vector pattern when transmitted electrically at the transmission rate via the communication channel falls within the passband associated with the communication channel.

Abstract: An object is to provide a redundant supervisory control system and a redundancy switching method thereof. In the redundant supervisory control system, remote I/O apparatuses are less likely to be inaccessible, even in a case where failures occur in plural locations. Thus, the reliability of the system is enhanced. The redundant supervisory control system including a plurality of first loop interface units in each of a pair of controllers, second loop interface units, and communication cables each connecting the plurality of first and second loop interface units with one another in a circular loop. The redundant supervisory control system is configured by connecting the controllers and the remote I/O units to one another in a plurality of loop networks. In a case where abnormality in the loop networks is detected by use of received data in the networks, the first and second loop interface units that can perform normal reception are automatically selected.

Abstract: In general, techniques are described for efficient management of ring networks with a system of two network devices. The first network device of the ring network is designated as an adjacent selective forwarding (ASF) device, and the second network device is designated as a master device. The master device monitors the ring network to determine whether a fault has occurred in the ring network and transmits via a secondary port of the master device a network status message to the ASF device based on the determination of whether the fault has occurred. The ASF device determines a status of the ring network based on the network status message and selectively forwards data traffic to the master network device based on the determination of the status. As a result, the master device more efficiently utilizes network resources by not consuming processor or memory resources to prevent traffic loops.

Abstract: The present invention provides an Ethernet ring system, transit node of Ethernet ring system, and initialization method thereof, wherein the method includes the following steps: step 1, generating a transit node of Ethernet ring protection domain by means of ring nodes; step 2, detecting the link state of two ring ports by means of the transit node: if neither of the two ring ports is detected as in-fault, then recording ring the link state as initialization state, blocking at least one of the ring ports, setting the at least one blocked port in prerelease state, and sending a ring state query packet to a master node, by means of the transit node; step 3, when the ring state query packet is received, sending a ring state packet recorded by the master node to the ring port that receives the ring state query packet, by means of the master node; and step 4, checking whether the ring state packet sent by the master node have been received by the transit node of which the ring state is the initialization state; if

Abstract: A real-time ring-loop surveillance network system is provided. By using digital communication network, multiple channels of media data and control data are transmitted in a ring-loop. The media data includes any forms of digital audio and video data, which is transmitted through 802.3/802.3u physical layer interface. The media data reaches all the stations in the network at the same time, and the number of the stations in the system depends on the system requirements. The number of the channels depends on the transceiver's speed. The present invention defines frames to encompass the media data and control data for transmission. The point-to-point delay is less than 0.15 ms. When 32 stations are connected in a ring-loop, the maximum delay is less than 5 ms. A backup mechanism is also included to detect and automatically switch to maintain the normal operation of the surveillance network system. The monitor signals are also encompassed in frames transmitted in the same network.

Abstract: A method for providing inter-ring protection in shared packet rings includes identifying an active node which is connected to a ring interconnect node on the same ring as the active node and connected to a peer node on a different ring with a ring interconnecting link. When the active node is in active mode and receives notification of a failure of the ring interconnecting link or peer node, the active node sends a message to the ring interconnect node so that the ring interconnect node switches from standby mode to active mode. The active node is then changed to standby mode.

Abstract: A communication network has an open-ended communication loop coupled to a communication ring at separate points on the ring. The communication network has wireless access points that are coupled to the loop. The wireless access points exchange user communications in a wireless communication format with user wireless communication devices. The wireless access points exchange the user communications with a service center over the communication loop and the communication ring. The wireless access points re-route the user communications to avoid a fault on the loop.

Abstract: In one embodiment, a method includes receiving a multicast join message at a node having a plurality of interfaces, identifying the interface at which the join message was received, and selecting one or more of the interfaces to transmit the join message based on whether the join message was received on a ring interface. If the join message was received on one of the ring interfaces, the join message is transmitted on another of the interfaces. If the join message was not received on one of the ring interfaces, the join message is transmitted on both of the ring interfaces. The method further includes receiving multicast data and transmitting the multicast data on the interface at which the join message was received.

Abstract: A network having a plurality of nodes interconnected by links (virtual communication channels) is disclosed. In one embodiment, the nodes may communicate with each other in a decentralized or peer-to-peer manner. A method for establishing the links among the nodes is disclosed. The links may be established such that the system is able to operate efficiently. In particular, the manner in which the nodes are interconnected by links may enable the system to efficiently route messages and efficiently recover from network failures.

Abstract: The invention described herein provides a system and method for fault isolation and auto-recovery in chained loop or ring networking systems (103). According to aspects of the method and the associated path-selection algorithms described, fault isolation and auto-recovery operations can be handled locally on each node on a loop and the overall fault recovery time under a link failure condition can be minimized. In addition, the method allows for auto-recovery operations that are transparent to the rest of network and to remote hosts.

Abstract: A novel fast and scalable protection mechanism for protecting hierarchical multicast service in ring based networks. The mechanism of the present invention is especially suitable for use in Multi-Protocol Label Switching (MPLS) ring based networks such as Metro Ethernet Networks (MENs). The mechanism provides fast protection for MPLS based point-to-multipoint (P2MP) Label Switched Paths (LSPs) in a scalable manner. Each multicast connection on each ring in the network is split into two sub-LSPs: a primary P2MP sub-LSP originating on a primary node and a secondary P2MP sub-LSP originating on a secondary node traveling opposite to the primary path. For each node to be protected, a point-to-point protection tunnel is provisioned from that node to a secondary node that forwards the packets to the secondary path on all child rings connected to that parent ring through the protected node and that are provisioned to receive the specific multicast connection.

Abstract: When a plurality of sub-processors are daisy chained in a loop, for example, to a main processor by a one-way bus, a command packet from the main processor addressed to itself is transmitted to the one-way bus which form a return path back to the main processor so as to easily specify a fault portion. If the command packet is returned to the main processor within a predetermined time, it is determined that no fault exists within the electronic device. When a fault exists, a test signal is transmitted to sub-processors via a dedicated signal line, separate from the one-way bus, to trigger a test packet that will be routed through the one way bus. The faulty portion in the electronic device is specified based on whether the test packet transmitted via the one-way bus in accordance with the test packet from each sub-processor is received within a predetermined time.

Abstract: A layer three enabled layer two network includes a multi service platform. The platform includes a layer two switching component and a layer three switching component and has a physical loopback connected between the layer two switching component and the layer three switching component. The layer two switching component is a terminating point for connections of the layer two network, enabling end-to-end layer two connections. The physical loopback enables the layer three features while increasing reliability of end-to-end connections across the network, and simplifying provisioning of layer three enabled layer two networks.

Abstract: Described are a system and method of communicating status and protection information between cards in a communications system. The system has a plurality of cards connected to a backplane. The plurality of cards includes a tributary card and a cross-connect card for forwarding data traffic between cards in the network element. The backplane has a link that is dedicated to carrying out-of-band signals between the tributary card and the cross-connect card. The tributary card transmits information to the cross-connect card in a first out-of-band signal over the link and the cross-connect card broadcasts the information to the plurality of cards in the network element in a second out-of-band signal.