Method to route packets in a distributed direct interconnect network
The present invention provides a method and apparatus to route data packets across a torus or higher radix topology that has low latency, increased throughput and traffic distribution to avoid hot spots development. Disclosed is a method of routing packets in a distributed direct interconnect network from a source node to a destination node comprising the steps of: discovering all nodes and associated ports; updating the database to include the nodes and ports in the network topology; calculating the shortest path from every output port on each node to every other node in the topology; segmenting each packet into flits at the output port of the source node; as the flits are segmented, distributing said flits along the shortest path from each output port on the source node to the destination node using wormhole switching, whereby the packets are distributed along alternate maximum disjoint routes in the network topology; and re-assembling and re-ordering the packets at the destination node so that the packets accord with their original order/form.
1. A computer-implemented method of routing packets in a direct interconnect network from a source node to a destination node comprising the steps of:
discovering all nodes and all output ports on each node in a network topology;
including the discovered nodes and output ports in the network topology in a topology database in order to allow said nodes and ports to be included in shortest path routing computations;
calculating the shortest path from every output port on each node to every other node in the network topology based on those nodes and output ports contained in the topology database;
generating a source routing database on each node containing the shortest paths from every output port on said each node to all other nodes in the network topology;
receiving packets at the source node;
sending the received packets to the output ports of the source node in a round robin or weighted round robin manner, whereby each of said received packets is thereafter segmented into flits at the output port of the source node and distributed along the shortest path from the output port on the source node to the destination node, such that the packets are thereby distributed along alternate routes in the network topology; and
re-assembling and re-ordering the packets at the destination node so that the packets accord with their original form and order.
2. The computer-implemented method of claim 1 wherein the flits are forwarded to the destination node using wormhole switching.