Method and arrangement for providing multi-level priority in a rotating priority arrangement for access to medium in an ethernet network

In network stations coupled to media of a network, a method of accessing the media, comprising:

• determining a priority level of a data packet to be transmitted;
• determining non-activity on the media;
• determining a wait time following the determination of non-activity on the media to transmit the data packet, the wait time being a function of the priority level of the data packet to be transmitted and a current priority of the network station among the network stations on the network for that data priority level;
• and
• transmitting the data packet on the medium after the determined wait time following the determination of non-activity on the media, if there is currently no activity on the media;
• wherein the priority levels of data packets include a low priority level and a high priority level, and further comprising the step of generating collision identification signals, said collision identification signals including a signal indicating a collision between a plurality of high priority level data packets, a signal indicating a collision between a plurality of low priority level data packets, and a signal indicating a collision between a high priority level data packet and a low level priority data packet.

A method of controlling access by network stations to a medium of a network, comprising the steps of:

• initializing a current priority for each network station, for a corresponding data packet to be transmitted by that network station from a selected one of multiple priority levels of data packets, each network station, maintaining its current priority for each corresponding data packet;
• each network station attempting access to the medium upon expiration of a period of time following the medium becoming available for transmission, if the medium is still available at the expiration of the period of time, the period of time for that network station being dependent on the current priority for that network station for a priority level of the corresponding data packet to be transmitted by that network station;
• and
• updating each period of time in each network station on the network after transmission of a data packet by one of the network stations, to thereby update the current priority in each network station from the multiple priority levels of data packets.

A network interface for connection with media of a network, comprising:

• a carrier sensor sensing deassertion of a carrier on the media;
• a programmable timer counting a wait time in response to the sensed deassertion of said carrier, the wait time including an interpacket gap interval and an integer multiple of a slot time;
• a memory that stores a plurality of the wait times for the network interface, with a separate wait time provided for each data priority level;
• a controller that programs the timer to count the wait time stored in the memory for the data priority level of a data packet to be transmitted by the network interface;
• and
• a transmitter outputting the data packet onto the media in response to a determined absence of activity by said sensor during the wait time.