Abstract: A system provides more cost and bandwidth efficient utilization of a SONET network having both a Working path and a Protection path by using both communication paths to carry data. A system for communicating data over a Synchronous Optical Network/Synchronous Digital Hierarchy, the system comprises an Optical Line Termination unit operable to interface with a plurality of Synchronous Optical Network/Synchronous Digital Hierarchy communication paths, and communicate different data on each of the plurality of Synchronous Optical Network/Synchronous Digital Hierarchy communication paths.

Abstract: A hash function for a MAC bridge filter that improves bridge performance by reducing overflow of the MAC bridge database and which reduces cost of the device by using relatively few hardware resources. A CRC hash function is used to randomize the search string in the MAC bridge filter so that a consistent bridge performance is achieved regardless of where the bridge is used. Using the CRC as a hash function also results in efficient hardware implementation. In addition, the present invention may be generalized to use a CRC-M as hash function for any bridge filter design.

Abstract: A communications network employs an optical communications medium carrying a synchronous communications transport signal including a number of time-division-multiplexed (TDM) channels. A number of bridges include respective interfaces to associated local area network (LAN) segments, and the bridges are coupled to the communications medium by associated add-drop circuits. Each add-drop circuit groups the TDM channels of the transport signal into bundles, each bundle being associated with a different bridge. Each add-drop circuit transmits data traffic originated by the associated bridge on only the bundle associated with the bridge, receives data traffic from the other bridges via the bundles associated with the other bridges, forwards the received data traffic to the associated bridge, and re-transmits at least some of the received data traffic on the bundles for receipt by another of the add-drop circuits.

Abstract: A communications network includes a communications medium with a synchronous communications transport signal including time-division-multiplexed (TDM) channels, bridges having respective interfaces to different local area network (LAN) segments, and add-drop circuits coupling associated ones of the bridges to the communications medium. Each add-drop circuit groups TDM channels of the communications transport signal into a bundle, and schedules the use of the bundle to carry data traffic originated by the associated bridge and to carry data traffic originated by the other bridges. Data traffic originated by the associated bridge and destined for the other bridges is transmitted on the bundle in accordance with the scheduling. For data traffic received from the other bridges via the bundle, it is determined whether the received data traffic is destined for the associated bridge, and if so then it is forwarded to the associated bridge.

Abstract: A network device transfers variable-length data frames across a synchronous network employing a multiple-channel synchronous transport signal. Encapsulation logic encapsulates each data frame in a point-to-point frame including a body portion of the data frame and a length value located in a beginning portion of the point-to-point frame. Segmentation logic divides each point-to-point frame into fixed-sized segments, a first segment carrying the beginning portion of the point-to-point frame. Transmitting circuitry transmits the frame segments as payloads of at least one channel of the synchronous transport signal, the payloads being marked so as to be identifiable. Receiving circuitry receives payloads of at least one channel of the synchronous transport signal and from each received set of payloads regenerates a corresponding point-to-point frame using the length value from the first segment thereof.

Abstract: A system and method provides a rate limiting technique in which user traffic is not thrown away and which provides improved performance over conventional techniques. A method of rate limiting in a Local Area Network/Wide Area Network interface comprises the steps of receiving data from the Local Area Network, storing the received data in a first buffer, transmitting the received data from the first buffer to the Wide Area Network, transmitting a PAUSE frame to the Local Area Network to cause the Local Area Network to stop transmitting data, if the first buffer fills to an upper threshold, and transmitting a PAUSE frame with PAUSE=0 to the Local Area Network to cause the Local Area Network to start transmitting data, if the first buffer empties to an lower threshold.

Abstract: A system provides more cost and bandwidth efficient utilization of a SONET network having both a Working path and a Protection path by using both communication paths to carry data. A system for communicating data over a Synchronous Optical Network/Synchronous Digital Hierarchy, the system comprises an Optical Line Termination unit operable to interface with a plurality of Synchronous Optical Network/Synchronous Digital Hierarchy communication paths, and communicate different data on each of the plurality of Synchronous Optical Network/Synchronous Digital Hierarchy communication paths.

Abstract: A LAN Service Unit (LANSU) backplane extender provides an inexpensive way to increase LANSU backplane bandwidth so that the performance degradation that may otherwise result can be avoided.

Abstract: A system and method provides flow control that can be implemented for any LAN/WAN technology combination. A Local Area Network Service Unit comprises a first device having a Local Area Network interface and a second interface, the first device operable to perform MAC level operation, statistics gathering, and bridging functions, and a second device having a Wide Area Network interface and a second interface to the second interface of the first device, the device operable to perform Wide Area Network data encapsulation and decapsulation and transmit and receive buffering.

Abstract: A network device transfers variable-length data frames across a synchronous network employing a multiple-channel synchronous transport signal. Encapsulation logic encapsulates each data frame in a point-to-point frame including a body portion of the data frame and a length value located in a beginning portion of the point-to-point frame. Segmentation logic divides each point-to-point frame into fixed-sized segments, a first segment carrying the beginning portion of the point-to-point frame. Transmitting circuitry transmits the segments frame as payloads of at least one channel of the synchronous transport signal, the payloads being marked so as to be identifiable. Receiving circuitry receives payloads of at least another channel of the synchronous transport signal and from each received set of payloads regenerates a corresponding point-to-point frame using the length value from the first segment thereof.

Abstract: A communications network includes a communications medium with a synchronous communications transport signal including time-division-multiplexed (TDM) channels, bridges having respective interfaces to different local area network (LAN) segments, and add-drop circuits coupling associated ones of the bridges to the communications medium. Each add-drop circuit groups TDM channels of the communications transport signal into a bundle, and schedules the use of the bundle to carry data traffic originated by the associated bridge and to carry data traffic originated by the other bridges. Data traffic originated by the associated bridge and destined for the other bridges is transmitted on the bundle in accordance with the scheduling. For data traffic received from the other bridges via the bundle, it is determined whether the received data traffic is destined for the associated bridge, and if so then it is forwarded to the associated bridge.

Abstract: A communications network employs an optical communications medium carrying a synchronous communications transport signal including a number of time-division-multiplexed (TDM) channels. A number of bridges include respective interfaces to associated local area network (LAN) segments, and the bridges are coupled to the communications medium by associated add-drop circuits. Each add-drop circuit groups the TDM channels of the transport signal into bundles, each bundle being associated with a different bridge. Each add-drop circuit transmits data traffic originated by the associated bridge on only the bundle associated with the bridge, receives data traffic from the other bridges via the bundles associated with the other bridges, forwards the received data traffic to the associated bridge, and re-transmits at least some of the received data traffic on the bundles for receipt by another of the add-drop circuits.

Abstract: LAN interface logic (33) receives frames from a LAN segment (32), and frame transport logic (40, 54, 56) transfers frames to and from an ATM network. Forwarding logic (36) is used to (i) determine whether a mapping between a destination address (DA) and a virtual connection (VC) in the ATM network exists, (ii) forward frames containing a known DA to the frame transport logic for transfer to the ATM network, (iii) forward frames containing unknown DAs to the frame transport logic for transfer to a broadcast and unknown server (BUS 74) in the ATM network, and (iv) pass unknown DAs to a LAN emulation client (LEC) processor (42, FIG. 5) to resolve the address. The LEC processor creates a LAN emulation address resolution protocol (LE_ARP) request message containing the unknown DA, and the LE_ARP request message is transferred to a LAN emulation server (LES 76). The LES returns an ATM address of a remote LEC via which the destination node can be reached.