Abstract: A network switch arrangement and method for providing a common architecture for queuing and dequeuing of data frames as they are transferred from a switch port to an external memory and similarly retrieved from the external memory to the switch port, irrespective of the particular data rate of the port. Logic controlling the actual data path is partitioned from logic responding to port data rate information by providing a “handshaking” communication arrangement between the two logics independent of the data rate. Hence, scalability of the data path over a wide range of data rates may be achieved while maintaining a single, common logic architecture.

Abstract: A method and apparatus in a network switch port for providing queuing of data frames as they are transferred from a switch port to an external memory. Multiple buffers within the external memory used to store a single data frame are linked together by writing a next buffer location in each buffer header. Storing linking information within each buffer eliminates the need for a separate memory for storing all the buffer locations used to store a data frame, thereby reducing the complexity and cost of the network switch port.

Abstract: The present invention is directed to methods and systems for estimating the log base-2 of a fixed point binary number using a single polynomial for an entire possible range of input numbers. An estimation of the log base-2 of a fixed-point binary number in either hardware or software may be implemented using a minimal number of parameters. In particular, a single 2nd order or greater polynomial may be sufficient to cover an entire range of input values for any arbitrary input word precision. The present invention provides a method and system for estimating a logarithm of a number where a linear approximation of a fractional part is determined and the linear approximation is implemented in a single polynomial function for estimating the fractional part for a range of input values.

Abstract: An arrangement and method of operating a network switch arrangement in a packet switched network connects a plurality of multiport network switches which is in a circular, serial manner so that data is transferable between the network switches only unidirectionally. When it is determined that data is to be transmitted from a first network switch to a port in a second network switch, the data is transmitted over an expansion bus from the first network switch to the second network switch in a continuous stream of data bursts. This extremely fast transmission between the networks switches allows multiple multiport network switches to be cascaded together to effectively form a single network switch with at least twice as many ports.

Abstract: A multiport data communication system for switching data packets between ports having a memory storing received data packets and a plurality of ports for transmitting and receiving data packets. Each transmit port has a transmit queue storing data packets to be transmitted from the respective port. The system includes a plurality of output queues, each corresponding to a respective port and storing frame pointers that point to where the data packets are stored in the memory. A plurality of dequeuing logic circuitry is provided corresponding to the plurality of ports. Each dequeuing logic circuitry reads respective frame pointers from the plurality of queues, reads the respective data packets corresponding to the respective frame pointers from the memory, and writes each read data packet to the corresponding transmit queue. The operations of each dequeuing logic circuitry are carried out in a pipelined manner in order to fully utilize the bandwidth of the external memory and speed up the dequeuing process.

Abstract: A network switch having switch ports for full-duplex communication of data packets with respective network nodes according to Ethernet (IEEE 802.3) protocol dynamically allocates external memory bandwidth slots between high data rate ports. An external memory interface determines if a high data rate port makes a request for a bandwidth slot and grants the request if made. The slot is taken from a selected group which is a subset of the total number of slots. If a request for the slot is not made, the external memory interface assigns the slot to another high data rate port. Lower data rate ports in the network switch are assigned fixed slots from those slots not from within the selected group of slots. The dynamic allocation of bandwidth slots between the high data rate port enables the efficient use of limited memory bandwidth resources.

Abstract: A multiport data communication system for switching data packets between ports comprising a plurality of receive ports for receiving data packets, a memory storing the received data packets, and a plurality of transmit ports each having a transmit queue. Logic circuitry for each transmit port controls reading from memory data corresponding to each data packet to be transmitted from the respective transmit port, reassembling the data read from the memory, and writing the reassembled data to the corresponding transmit queue. A monitoring circuit monitors the received data packets prior to storing them in the memory and determines whether a respective data packet should have the VLAN tag inserted/stripped/modified and/or the Device ID inserted/stripped.

Abstract: A multiport data communication system for switching data packets between ports includes a plurality of receive ports for receiving data packets, a plurality of transmit ports for transmitting data packets, circuitry deciding whether each received data packet is one of high priority and low priority, and a memory for storing each received data packet. A memory location designator is provided for each data packet indicating where the corresponding data packet is stored in the memory and a plurality of queuing devices corresponding to the plurality of transmit ports queue the memory location designators. Each queuing device has a high priority queue queuing memory location designators corresponding to data packets of high priority to be retrieved from the memory an transmitted by the respective transmit port and a low priority queue queuing memory location designators corresponding to data packets of low priority to be retrieved from the memory and transmitted by the respective transmit port.

Abstract: A network switch having switch ports for full-duplex communication of data packets with respective network nodes according to Ethernet (IEEE 802.3) protocol that allocates a prescribed number of external memory bandwidth slots between high data rate ports based on the compared amount of network traffic on the respective ports. A scheduler within an external memory interface initially assigns memory access slots to the respective high data rate ports according to a prescribed sequence. If the scheduler subsequently detects that the network data traffic on a port having less slots is higher than the traffic on a port having more slots, the slots are swapped between the high data rate ports. Additionally, a clock multiplexer in one of the high data rate ports adjusts the data rate of the port dependent upon the number of slots assigned to that port.

Abstract: A multiport data communication system for switching data packets between ports comprising a plurality of receive ports for receiving data packets, a memory storing the received data packets, and a plurality of transmit ports each having a transmit queue. Logic circuitry for each transmit port controls reading of a data packet from memory, provides a control signal indicating an end of reading the data packet from the memory, decides whether a length of the read data packet is to increase, decrease, or remain the same, controls writing the read data packet to a corresponding transmit queue in accordance with the decision, and provides a signal indicating an end of writing the data packet to the transmit queue.

Abstract: A network switch having a shared memory architecture for storing data frames has a set of programmable thresholds that specify when flow control should be initiated on a selected network port. The network switch includes a queue for storing free frame pointers, each specifying available memory locations in an external memory for storing data frames received from a network station. The network switch takes a frame pointer from a free buffer queue for each received data frame, and stores the received data frame in the location in external memory specified by the frame pointer while a decision making engine within the switch determines the appropriate destination ports.

Abstract: A method and arrangement for transmitting multiple copies of a frame from a network switch in a packet switched network stores a single copy of the frame received at the switch into external memory. The frame is stored at a location in memory pointed to by a frame pointer. In queuing multiple transmissions of the stored frame in the switch, the frame pointer, and not the frame itself, is replicated and queued for transmission in the network switch.

Abstract: An interface for use in a data forwarding device is connected between the receive ports and transmit ports of a device. The interface ensures that data being forwarded from a receive port to a transmit port has actually been received. The interface includes a queuing circuit and a de-queuing circuit. The queuing circuit receives data from the receive port, identifies the receive port, counts the data received, and buffers the data. The de-queuing circuit retrieves the buffered data at a scheduled time based on the receive port's mode, and forwards the data to a transmit port provided that the amount of data received by the queuing circuit is at least as great as the amount of data already forwarded by the de-queuing circuit plus a threshold safe level amount of data.

Abstract: Pharmaceutical compositions in topical or parenteral form containing specific organic mono- or dinitrates, some of them novel compounds, are effective in treating male impotence and erectile dysfunction through topical or intracavernosal administration to the penis. Methods of treatment utilizing the mono- or dinitrate-containing compositions are also disclosed.

Abstract: Pharmaceutical compositions in topical or parenteral form containing organic nitrites are effective in treating male impotence and erectile dysfunction through topical or intracavernosal administration to the penis. Methods of treatment utilizing the nitrite-containing compositions are also disclosed, as are certain novel organic nitrite compounds.

Abstract: A method of treating a patient suffering from a condition requiring vasodilator therapy, comprising long term, continuous adminstration of an organic nitrite to the patient in a dosage form capable of delivering a sufficient therapeutic amount of nitrite to the bloodstream of the patient thereby providing effective vasodilator therapy for at least 24 hours without the development of tolerance in the patient. The method of the invention is useful in treating conditions such as angina, particularly chronic, stable angina pectoris, ischemic diseases and congestive heart failure, and for controlling hypertension and/or impotence in male patients.

Abstract: The present invention provides a novel method of vasodilator therapy for treating a patient suffering from a condition, comprising long term, continuous administration of an organic nitrite to a patient suffering from the condition in a dosage form capable of delivering a sufficient therapeutic amount of nitrite to the blood stream of the patent thereby providing effective vasodilator therapy for at least 24 hours without development of tolerance in the patient. The method of the invention is useful in treating conditions such as, for example, angina, particularly chronic, stable angina pectoris, ischemic diseases, congestive heart failure, for controlling hypertension and/or impotence in male patients.Any conventional drug delivery system can be employed in carrying out the method of the invention. The drug delivery system can take virtually as many different forms as there are dosage forms available for delivery of nitrite to a patient.

Abstract: There is described an aqueous pharmaceutical solution comprising a steroid selected from prednisolone, prednisolone sodium phosphate, prednisone and methyl prednisolone, the steroid being present at a concentration of at least 0.3 mg/ml., the pH of the formulation between 5 and 8 and the formulation containing a pharmaceutically acceptable preservative, a pharmaceutically acceptable chelating agent, and being substantially free of ethanol.There is also described a method of treatment of a variety of conditions, particularly in children, using the solution.