Scheme for avoiding deadlock in multi-ring interconnect, with additional application to congestion control

A network comprising:

• at least one source station;
• at least one target station;
• at least one source slotted ring interconnect comprising a plurality of slots, the source station operably connected to the source slotted ring interconnect;
• at least one target slotted ring interconnect comprising a plurality of slots, the target station operably connected to the target slotted ring interconnect, wherein the target slotted ring interconnect and the source slotted ring interconnect are different;
• and
• at least one ring connector connecting the source slotted ring interconnect and the target slotted ring interconnect,
• wherein the source station is configured to transmit a message to one of the plurality of slots of the source slotted ring interconnect such that the message travels around the source slotted ring interconnect,
• wherein, if the ring connector or the target station is able to receive the message, the ring connector or the target station is configured to remove the message from the source slotted ring interconnect, otherwise the ring connector or the target station is configured to mark the message with a negative flag, and the source station is configured to remove the message marked with the negative flag from the source slotted ring interconnect, such that the message travels no more than one time around the source slotted ring interconnect before removal.

A method to avoid multi-ring deadlock comprising:

• putting a message from a source station in a slot of a source slotted ring interconnect directed to a target station on a target slotted ring interconnect, wherein the source slotted ring interconnect and the target slotted ring interconnect are not the same;
• allowing the message to travel around the source slotted ring interconnect;
• and
• if the target station is able to receive the message, removing the message from the source slotted ring interconnect either with a ring connector connecting the source slotted ring interconnect and the target slotted ring interconnect or by the target station, and
• if the target station is not able to receive the message, marking the message with a negative flag and removing, by the source, the message marked with the negative flag from the source slotted ring interconnect, such that the message travels no more than one time around the source slotted ring interconnect before removal.