Ring interconnect system architecture

An improved computer system interconnection for use within a computer system, the computer system including a plurality of components, the interconnection comprising a plurality of nodes, each node being associated with one of the plurality of components, each node being coupled to an upstream node via a first transmission means, the first transmission means receiving information from other nodes, each node being coupled to a downstream node via a second transmission means, the second transmission means transmitting information to the other nodes, the information including:

• a multiplicity of symbol streams, each symbol stream including a multiplicity of symbols of data, each symbol having a type, symbol types including data symbols and access symbols, access symbols including voucher symbols and ticket symbols, each voucher symbol representing a request for reservation of data space in a target node, each symbol including a target bit indicative of a target node, a source bit indicative of source node and urgency bits indicative of a level of urgency of the symbol data, each node comprising:
• 1) source buffering means for receiving information from the node's associated component, the source buffering means organizing information from the node according to streams and urgency bits, streams coming from the node having a first source level urgency or a second source level urgency, the first source level urgency and the second source level urgency each being one of the levels of urgency, the first source level of urgency being a greater level of urgency than the second level of source urgency, symbols from the source buffering means having a third priority;
• 2) relay buffering means for relaying symbols received from the first transmission means whose target bits indicate that they are targeted at other nodes, the relay buffering means including one buffering means for each level of urgency, symbols from the relay buffering means having the third priority;
• 3) voucher generation means for generating voucher symbols when the node's associated component inputs information targeted at other nodes, symbols from the voucher generation means having a second priority;
• 4) a first routing means responsive to voucher symbols received via the first transmission means targeted at the node, the routing means determining whether the node's associated component is able to receive information;
• 5) target handling means responsive to the determination that the node's associated component is able to receive information, the target handling means responding by generating a ticket symbol indicating reservation of data space, symbols from the target handling means having a first priority;
• 6) source handling means responsive to receipt of ticket symbols indicating that a target node is prepared to receive information from the node, the source handling means responding by enabling the source buffering means to release information to be transmitted to the target node associated with the ticket received;
• and
• 7) a downstream routing means for coupling to the second transmission means symbols from the source buffering means, relay buffering means, voucher generation means and target handling means according to symbol priority and urgency level, the downstream routing means coupling symbols with lowest priority to the second transmission means before symbols with higher priority and when symbols have equal priority levels the downstream routing means coupling symbols with higher urgency levels before symbols with lower urgency levels.