 
Summary: The zeroone principle for switching networks
Yossi Azar Yossi Richter y
Abstract
Recently, approximation analysis has been extensively used to study algorithms for routing
weighted packets in various network settings. Although dierent techniques were applied in the
analysis of diverse models, one common property was evident: the analysis of input sequences
composed solely of two dierent values is always substantially easier, and many results are known
only for restricted value sequences. Motivated by this, we introduce our zeroone principle
for switching networks which characterizes a wide range of algorithms for which achieving c
approximation (as well as ccompetitiveness) with respect to sequences composed of 0's and
1's implies achieving capproximation. The zeroone principle proves to be very eÆcient in
the design of switching algorithms, and substantially facilitates their analysis. We present
three applications. First, we consider the MultiQueue QoS Switching model and design a 3
competitive algorithm, improving the result from [6]. Second, we study the Weighted Dynamic
Routing problem on a line topology of length k and present a (k + 1)competitive algorithm,
which improves and generalizes the results from [1, 11]. As a third application, we consider
the work of [14], that compares the performance of local algorithms to the global optimum in
various network topologies, and generalize their results from 2value sequences to arbitrary value
sequences.
1 Introduction
