Abstract: Automatic detection by a port of the type of device connected by a cable to the port is accomplished by transmitting a control packet by the device, where the control packet has a nonstandard format. The port examines received packets for the nonstandard format. Upon detection of a packet having the nonstandard format, the port recognizes that the source device of the packet is of a predetermined type which transmits control packets of the nonstandard format. Further, by choosing the nonstandard format so that typical forwarding devices will not forward the nonstandard packet, the port is assured that the source device is attached to the port by a cable. That is, by choosing a nonstandard packet which is not forwarded by a bridge or router, the port is assured that the packet has not been forwarded from a remote part of the network.

Abstract: A method implemented by a computer network adapter for automatic retransmission of any packet involved in an unsuccessful transmission attempt due to transmit buffer underflow conditions entails the steps of (a) stopping the transmission; and (b) retrying another transmission of the packet for up to a predetermined number of attempts with an increased transmit threshold. The transmit threshold is the number of bytes of data of the packet involved in the transmission that are stored in the transmit buffer prior to start of transmission. Preferably, for the initial transmission attempt, the adapter requires only a small number of bytes of the packet to be stored in the transmit buffer. After occurrence of a buffer underflow condition, the adapter attempts a retry in accordance with the algorithm only after a substantially larger portion of the packet has entered the transmit buffer for transmission. If any retry succeeds, the adapter need not issue an interrupt.

Abstract: A system for controlling the transmission of cells from a network node over multiple Virtual Circuits (VCs) is disclosed. The system performs traffic shaping, as required by connection based systems such as Asynchronous Transfer Mode (ATM), for each VC connected with a network node, so that the Quality of Service (Qos) parameters established when the connection was established are not exceeded. The system includes a process for scheduling the transmission of cells from the network node. The scheduling process periodically scans a table having entries corresponding to virtual circuits connected with the network node. During each scan of the table, the scheduler increments a sustainable rate accumulator field and a peak rate accumulator field of each table entry that corresponds with a virtual circuit that is open, and for which there is a cell ready to be transmitted.

Abstract: A system for controlling the transmission of cells from a network node over multiple virtual circuit is disclosed. The disclosed system performs traffic shaping for all virtual circuits connected with the network node. The system includes a virtual circuit table with one or more entries. Each virtual circuit table entry corresponds to a virtual circuit established with the network node. Each virtual circuit table further includes one or more Cell Rate Accumulator fields and a Time Stamp field. The system includes a schedule table having one or more entries. Each schedule table entry further includes one or more Cell Rate Accumulator fields and corresponding predetermined value fields. A schedule table loading process determines a virtual circuit on which a packet is to be transmitted, and then calculates a time elapsed since a last previous write of a virtual circuit table entry corresponding with that virtual circuit.

Abstract: An Asynchronous Transfer Mode (ATM) network device having a receiver portion capable of receiving ATM cells on one of a number of virtual circuits (VCs) from an upstream ATM switch, a local memory used to store the ATM cells, a management system to manage the local memory using a number of queues, a system for assembling ATM cells into packets, a system for transmitting the packets to a host memory, and a transmitter portion having a system for indicating the transmitting of packets to the host memory to the upstream ATM switch.

Abstract: The invention improves the efficiency of buffer descriptor processing by performing descriptor prefetches, where multiple descriptors are read within the same descriptor bus transaction. The invention reads multiple buffer descriptors each time the bus is accessed. This allows for a smaller FIFO in a cut-through network adapter because it reduces the number of bus transactions needed to transfer data.

Abstract: A method providing automating detection of configuration between an adapter device and a DRAM device. Such a method a determines, in the adapter memory, the DRAM configuration, making it easier to change DRAM configuration in an existing board without the need to modify configuration pins in the existing board. A method for determining a configuration type in an Asynchronous Transfer Mode (ATM) communications network comprising the steps of providing an ATM adapter, the ATM adapter having an ATM adapter memory, providing a DRAM device, the DRAM device having a DRAM configuration, providing a link to connect the ATM adapter and the DRAM device, assuming, in the ATM adapter memory, a first DRAM configuration, verifying the step of assuming, and repeating the steps of assuming and verifying until the first DRAM configuration is determined.

Abstract: A system for controlling the transmission of cells from a network node over multiple Virtual Circuits (VCs) is disclosed. The system performs traffic shaping, as required by connection based systems such as Asynchronous Transfer Mode (ATM), for each VC connected with a network node, so that the Quality of Service (Qos) parameters established when the connection was established are not exceeded. The system includes a process for scheduling the transmission of cells from the network node. The scheduling process periodically scans a table having entries corresponding to virtual circuits connected with the network node. During each scan of the table, the scheduler increments a sustainable rate accumulator field, a peak rate accumulator field, and a latency accumulator field of each table entry that corresponds with a virtual circuit that is open, and for which there is a cell ready to be transmitted.

Abstract: A host system and an ATM network adapter using a chaser packet are presented. The adapter receives cells over a virtual connection on the network and generates, in response to the host system, a chaser packet which allows the host to detect that all data has been transferred form the adapter buffers to host memory. When all data has been transferred, the host may release the virtual connection without data loss. The host and adapter may also transmit data. In data transmission, the chaser packet is used to determine that all data has been transmitted out onto the network before the sending host releases the virtual connection. The chaser packet is also used for resynchronization of credits where the ATM network uses credit-based flow control. The adapter uses the chaser packet to drain the local queue so that the link between the adapter and a source system may be resynchronized.