Routing arbitration for shared resources

In a data communication device having a plurality of inputs and at least one output, the data communication device operating to receive data at the plurality of inputs for re-transmission from the output, apparatus for selecting among a number of the plurality of inputs having data for communication to and from the output, the apparatus comprising:

• for each the plurality of inputs:
• (a) an arithmetic unit coupled to receive an assigned value to produce therefrom a modified value that is changed by the assigned value when such one of the plurality of inputs participates in arbitration for access to the output;
• (b) a counter coupled to the arithmetic unit to increment a count when the modified value equals or exceeds a predetermined value;
• and
• arbiter logic to receive the count from each of the plurality of inputs to select a one of the number of inputs for communication of data from the one of the number of inputs to the output according to a first order when the count is a first value, and to select the one of the number of inputs according to a second order when the count from any of the plurality of inputs is not the first value.

A method of granting one of a number of data elements access to a shared communication medium, the method including the steps of:

• for each of the number of data elements,
• providing the data element with an assigned bias value;
• developing from the assigned bias value an accumulated value;
• maintaining a count value that is indicative of each time the accumulated value realizes a predetermined value;
• selecting the one of the data elements for access to the shared medium on a first predetermined basis when the counts of the data elements are equal;
• selecting the one of the data elements for access to the shared medium on a second predetermined basis when the count values of the data elements are all not equal.