Method and apparatus for integrated local and express routing in a

Abstract

A router for routing a message among nodes in an N dimensional network of processor nodes. The router includes a message logic unit determining in which direction the message is traveling in the network. The router features a number of (D) of express ports, each express port having an input for inputting and an output for outputting the message in a corresponding one of (D) express directions. A routing logic unit in the router is capable of transmitting the message in a selected express direction through a corresponding local port, each local port inputting and outputting the message in one dimension of the network. The routing logic unit also includes express routing logic that is capable of transmitting the message in the selected express direction through a corresponding express port. The message logic unit includes detection logic for determining the distance in each dimension remaining to be traveled by the message to a destination node. The routing logic unit transmits the message in the express direction through the express port if the remaining distance in the express direction is greater than or equal to a quantity S, where S is greater than or equal to 2N/D. The routing logic unit transmits the message in the express direction through the local port if the remaining distance in the express direction is less than S.