Abstract: Collision delay intervals are modified in Ethernet network devices transmitting priority data requiring a guaranteed latency by multiplying an integer multiple number of slot times with a fractional coefficient. A network device having priority data for transmission uses the conventional Truncated Binary Exponential Backoff (TBEB) algorithm during the first access attempt to calculate a collision delay interval from a randomly selected integer multiple of slot times. If the network device encounters another collision, the next randomly selected integer multiple of slot times is multiplied by the fractional coefficient. Use of the fractional coefficient during collision mediation on a half-duplex Ethernet network provides a bounded access latency for real-time and multimedia applications by granting the network device a higher probability of successfully accessing the network media.

Abstract: Delay times are modified in Ethernet network devices by adding an integer multiple of a delay interval to the minimum interpacket gap (IPG) interval, and decrementing a deferral counter storing the integer in each network station in response to detected activity on the media. Each station independently determines the number of stations active on the network media by counting the number of successful packet receptions following a corresponding detected collision. Once the number of detected collisions equals the number of stations (N) minus one, each station independently establishes a unique integer value from the range of zero to the number of detected collisions, i.e., up to the number of stations (N) minus one, by resetting the deferral counter to (N-1) after a successful transmission, and by decrementing the deferral counter upon detection of a successful transmission without collision by another station.

Abstract: Efficient communication in a network having a minimum data transmission time interval wherein a data packet is transmitted beginning at a start of the minimum data transmission time interval. An end of the minimum data transmission time interval is determined and then at least one next data packet is transmitted after the data packet if the end of the minimum data transmission time is after the end of the data packet.

Abstract: Delay times are modified in Ethernet network devices by adding an integer multiple of a delay interval to the minimum interpacket gap (IPG) interval, and decrementing the integer in each network station in response to detected activity on the media. Each station has a unique integer value from the range of zero to the number of stations (N) minus one. The unique integer value ensures that each station has a different delay interval in accessing the media after sensing deassertion of the receive carrier. The station having a zero integer value will have its integer counter reset to (N-1) after a station transmits a data packet on the network, and the stations having nonzero integer values decrement their respective integer counters. Each network station also includes a deferral timer that counts the maximum delay interval of (N-1) delay intervals plus the minimum IPG value, and thus establishes a bounded access latency for a half-duplex shared network.

Abstract: A network includes a combination of carrier-sense stations and Universal Multiple Access (UMA) stations using a time slot multiple access protocol. The network is configured to include assigned time slots for the respective UMA stations and unassigned time slots reserved for the carrier-sense stations to access the shared network media. Each of the UMA stations is provided with a corresponding assigned time slot and the total number of time slots. Since the UMA stations access the media only during the assigned time slot, the carrier-sense stations can contend for access to the media after waiting a minimum interpacket gap (IPG) after sensing deassertion of the receive carrier on the media. The UMA stations may also be modified to attempt access of the media using Ethernet-compliant, carrier-sense multiple-access with collision detection (CSMA/CD) protocol when a current time slot corresponds to a mixed-use time slot.

Abstract: A network system includes end nodes which are connected to a plurality of cascaded hubs. A two priority protocol is provided for selecting end nodes to send network packets over the network. When at least one end node in the network system has a high priority network packet to send, each end node with a high priority network packet is acknowledged in turn. Each end node, when acknowledged, sends its high priority network packet through the network. When no end nodes have a high priority network packet, and at least one end node in the network system has a normal priority network packet to send, each end node with a normal priority network packet is acknowledged in turn. This includes a root hub acknowledging in turn each second level hub which is connected to an end node which has a normal priority network packet to send. Each second level hub, when acknowledged, proceeds to acknowledge in turn each end node which is connected to the second level hub and which has a normal priority network packet.