Methods, apparatus, and products are disclosed for dispatching packets on a global combining network of a parallel computer comprising a plurality of nodes connected for data communications using the network capable of performing collective operations and point to point operations that include: receiving, by an origin
system messaging module on an origin node from an origin application messaging module on the origin node, a storage identifier and an operation identifier, the storage identifier specifying storage containing an application message for transmission to a target node, and the operation identifier specifying a
message passing operation; packetizing, by the origin
system messaging module, the application message into network packets for transmission to the target node, each
network packet specifying the operation identifier and an operation type for the
message passing operation specified by the operation identifier; and transmitting, by the origin
system messaging module, the network packets to the target node.