Comparison of Rate-Controlled Static Priority and Stop-and-Go
	
                       Hui Zhang and Edward W. Knightly
	                      EECS Department
	              University of California, Berkeley
		                  and
 		   International Computer Science Institute

To support emerging real-time applications, high speed integrated
services networks need to provide end-to-end performance guarantees on
a per-connection basis in a networking environment. In addition to the
issue of how to allocate resources to meet diverse QOS requirements in
a single switch, resource management algorithms also need to account
for the fact  that traffic may get burstier and burstier as it
traverses the network due to complex interaction among packet streams
at each switch.  To address this problem,  several non-work-conserving
packet service disciplines have been proposed that fully or partially
reconstruct the traffic pattern of the original source inside the
network.  This is achieved by a policing or delay-jitter control
mechanism in which packets may be held at intermediate switches in
order to keep the traffic from becoming burstier.  In this paper, we
compare two non-work-conserving disciplines: Stop-and-Go and
Rate-Controlled Static Priority or RCSP. Stop-and-Go uses a multi-level
framing strategy to allocate resources in a single switch and to ensure
traffic smoothness throughout the network.  RCSP decouples the server
functions by having two components: a regulator to partially or fully
reconstruct the traffic pattern and a static priority scheduler to
allocate delay bounds in a single switch.  We compare the two service
disciplines in terms of traffic specification,  scheduling mechanism,
buffer space requirement, end-to-end delay characteristics, connection
admission control algorithms, and achievable network utilization.  The
comparison is first done analytically, and then using MPEG compressed
video traces for numerical investigations into the properties of
practical real-time network sources.