Asynchronous transfer mode ring system with coupler and station at each node of network includes rationalized system of packet buffering priorities

摘要

Each coupler at a ring- and station input includes a direction- and priority controller. This forwards a packet (structured data cell) in accordance with its destination. It also outputs its priority to a buffer or directly to at least one ring- or station output. Direction and priority control is provided to forward the packet of highest priority classification (priority) which originates from a ring, and for the storage of packets having lower priority, in a ring buffer. A multiplexer coupled to the ring output forwards packets in accordance with the following descending priorities. Forwarding takes place first of a packet of the highest priority, originating from a ring input. It takes place next in priority from a station input originating packets of the highest priority, given that no highest priority packet from a ring input exists. Lower priority packets are forwarded next (given nothing of higher priority). Ultimately, packets originating from a station input of lower priority are forwarded, again in default of any higher priority packets.