Abstract: A method and structure for the distribution and utilization of synchronization within an asynchronous network is described herein. Synchronization is distributed through an asynchronous network via a synchronization symbol periodically inserted on the MAC layer. The priority of this symbol ensures that this symbol is inserted in the MAC layer data stream ahead of all other types of symbols. The insertion of the synchronization symbol in the middle of an ongoing data frame is supported. In addition, a method for synchronization symbol distribution throughout an asynchronous network is presented, along with a method for switching to a new synchronization path (in the event of loss of original synchronization path) based on minimum number of hops from the synchronization source.

Abstract: A method and system for synchronizing data between a management system (MS) and network elements (NE) in an optical network utilizes a table counter and row counters for each row in a NE table, and a table counter and row counter for each row in a MS table. The NE table counter increments when a change in the NE table occurs. Each NE row counter increments when its row is changed. The MS table counter increments when a change in the MS table occurs. Each MS row counter is incremented when its row is changed. The MS polls the NE table counter and compares it with its MS table counter. If they are different, then the MS compares each NE row counter with the corresponding MS row counter. For any of the row counters that do not match, the rows between the MS table and the NE table are synchronized.

Abstract: A communications network is described having a class-based queuing architecture. Shared class queues receive packet flows from different customers. In one embodiment, there are eight classes and thus eight shared queues, one for each class. A scheduler schedules the output of packets by the various queues based on priority. Each customer (or other aggregate of packet flows) is allocated a certain space in a class queue based on the customers' Service Level Agreement (SLA) with the service provider. A queue input circuit detects bits in the packet header identifying the customer (or other criteria) and makes selections to drop or pass packets destined for a shared queue based on the customers' (or other aggregates') allocated space in the queue.

Abstract: A system and method are disclosed for policy based accounting and billing for network services. In one embodiment, a packet forwarding device receives a packet to be forwarded over the network, accesses a policy table to identify a billing party associated with the packet, obtains billing information, and stores a record of the forwarded packet and the associated billing party.

Abstract: Error codes output from a serializer/deserializer in a node of a communications network are detected by error decode logic that assumes that each new error occurrence reflects a one bit error in the word giving rise to the error code. Each error occurrence is then counted. When the error count reaches a predetermined limit (e.g., 250 errors), the total bit count required to accumulate the 250 errors is then determined. The total bits can be determined based on a clock count (time). The BER is then calculated based upon the fixed error limit and the total bit count. This BER is then reported and used to determine the health of the network.

Abstract: The disclosed network includes two rings, wherein a first ring transmits data in a clockwise direction, and the other ring transmits data in a counterclockwise direction. The traffic is removed from the ring by the destination node. During normal operations (i.e., all spans operational), data between nodes flows on the ring that would provide the minimum number of hops to the destination node. Thus, both rings are fully utilized during normal operations. The nodes periodically test the bit error rate of the links (or the error rate is constantly calculated) to detect a fault in one of the links. The detection of such a fault sends a broadcast signal to all nodes to reconfigure a routing table within the node so as to identify the optimum routing of source traffic to the destination node after the fault.

Abstract: A dual addressing mode is described in which reduced-length addresses (referred to as short addresses) are substituted for standard addresses (referred to as long addresses) for traffic whose source or destination is internal to a given virtual network topology. The required length of short addresses used for a given virtual topology is dependent on the number of devices reachable within the topology. For a virtual topology with less than 256 addressable devices, for example, 8-bit short addresses can be used. When a node within the virtual network sees a packet with a short destination address in the header, the node understands the address to be within the virtual network and routes the packet accordingly. If a source address is a short address, the virtual network can identify the source within the virtual network. For packets originating in the virtual network whose destination is also in the virtual network, both the source and destination addresses can be short addresses.

Abstract: The disclosed network includes two rings, wherein a first ring transmits data in a clockwise direction, and the other ring transmits data in a counterclockwise direction. The traffic is removed from the ring by the destination node. During normal operations (i.e., all spans operational), data between nodes flows on the ring that would provide the minimum number of hops to the destination node. Thus, both rings are fully utilized during normal operations. The nodes periodically test the bit error rate of the links (or the error rate is constantly calculated) to detect a fault in one of the links. The detection of such a fault sends a broadcast signal to all nodes to reconfigure a routing table within the node so as to identify the optimum routing of source traffic to the destination node after the fault.

Abstract: An architecture for transport of multiple services in connectionless packet-based networks is described herein, along with the packet format used for data transport in this architecture. The architecture supports transport of both connectionless packetized data and framed data from synchronous leased lines. The architecture supports transparent packetization of incoming DS1 data. The architecture works for mesh architectures but is optimized for OSI Layer 1 (crossconnect) and Layer 2 (Virtual LAN, or VLAN) services and for ring topologies, since for these services in a ring no path setup is required using a label distribution protocol. In addition, it simultaneously supports OSI Layer 1, Layer 2, and Layer 3 services.

Abstract: An automatic network topology identification technique is described herein. Each node in the network periodically or constantly transmits its unique address to its neighboring node. Once a node receives a different message from its neighbor, the node identifies a topology change in the network. In one embodiment, a current topology is associated with a session number. When a change in the topology is detected, the detecting node increments the session number and broadcasts the change in topology. The other nodes, detecting the changed session number, now know that there has been a change in the network. In response, the nodes in the network modify routing tables and other information stored at the node related to the topology. In one embodiment, the technique is used to reassign shortened addresses to each device on the network to support a dual-addressing mode of the network.

Abstract: An automatic network topology identification technique is described herein. Each node in the network periodically or constantly transmits its unique address to its neighboring node. Once a node receives a different message from its neighbor, the node identifies a topology change in the network. In one embodiment, a current topology is associated with a session number. When a change in the topology is detected, the detecting node increments the session number and broadcasts the change in topology. The other nodes, detecting the changed session number, now know that there has been a change in the network. In response, the nodes in the network modify routing tables and other information stored at the node related to the topology. In one embodiment, the technique is used to reassign shortened addresses to each device on the network to support a dual-addressing mode of the network.

Abstract: A communications network is described having a class-based queuing architecture. Shared class queues receive packet flows from different customers. In one embodiment, there are eight classes and thus eight shared queues, one for each class. A scheduler schedules the output of packets by the various queues based on priority. Each customer (or other aggregate of packet flows) is allocated a certain space in a class queue based on the customers' Service Level Agreement (SLA) with the service provider. A queue input circuit detects bits in the packet header identifying the customer (or other criteria) and makes selections to drop or pass packets destined for a shared queue based on the customers' (or other aggregates') allocated space in the queue.