"Smooth Scheduling in a Cell-Based Switching Network"
Thomas L. Rodeheffer and James B. Saxe
Report #150, February 19, 1998
36 pages.

This paper describes a method for scheduling data cell traffic through a
crossbar switch in such a way as to guarantee that the time slots for
each flow, and optionally for certain aggregates of flows, are
approximately uniformly distributed throughout the duration of the
scheduling frame.  Such a "smooth" schedule achieves reductions in both
the latency of data flows and the need for associated buffering memory. 
The method can be used to compute smooth schedules even under conditions
of maximum load, where the bandwidth re-quirements of the flows to be
scheduled are sufficient to consume the entire capacity of the switch. 
This method has been implemented for a working high-speed ATM switching
network, AN2.  We describe the implementation, its performance, and
possible future improvements.