Method for distributing multipath flows in a direct interconnect network

A method of routing a flow of packets from a source node to a destination node, the method comprising:

• (a) commencing routing packets in a flow of packets from a source node to a destination node along multiple pathways, and including metadata with the packets describing the routing distribution of the packets along the multiple pathways, said metadata comprising a number of packets sent on each pathway within the multiple pathways, a Last Round Distribution (LRD) vector indicating paths used in a previous round of packet distribution, and a Round Sequence Number (RSN) that is incremented with each new round;
• (b) monitoring relative packet skew between the multiple pathways at the destination node, wherein the destination node counts the number of packets that arrive on each pathway within the multiple pathways, compares the number of packets that arrive on each pathway to the number of packets sent on each pathway as per the metadata, and determining path skew status based on this comparison, wherein the path skew status comprises per-path skew counter values that are incremented based on the LRD for packets sent on each path and decremented for packets arriving on each path;
• (c) using a backwards multipath control flit mechanism to send the path skew status from the destination node to the source node;
• and
• (d) implementing a weighted path distribution mechanism at the source node to dynamically reduce the use of or avoid any skewed pathways in the multiple pathways when routing packets from the source node to the destination node along multiple pathways.