Title: Dynamic Server Selection using Bandwidth Probing in Wide-Area Networks
Authors: Robert L. Carter  and Mark E. Crovella
Date: February 2, 1996

Abstract: 

   Replication is a commonly proposed solution to problems of scale 
associated with distributed services. However, when a service is 
replicated, each client must be assigned a server. Prior work has 
generally assumed that assignment to be static. In contrast, we propose 
dynamic server selection, and show that it enables 
application-level congestion avoidance.

   To make dynamic server selection practical, we demonstrate the use 
of three tools. In addition to direct measurements of round-trip latency,
we introduce and validate two new tools: bprobe, which estimates 
the maximum possible bandwidth along a given path; and cprobe, which 
estimates the current congestion along a path.

   Using these tools we demonstrate dynamic server selection and compare it
to previous static approaches. We show that dynamic server selection 
consistently outperforms static policies by as much as 50%. Furthermore, 
we demonstrate the importance of each of our tools in performing dynamic 
server selection.