Summary: 1
Achieving Stability in
Networks of Input­Queued Switches
Matthew Andrews Lisa Zhang
Abstract--- Recent research has generated many interest­
ing results on scheduling input­queued switches. However,
most of this work focuses on a single switch in isolation. In
this paper we study the problem of scheduling a network
of input­queued switches. We consider the Longest­Queue­
First and Longest­Port­First protocols that are stable for a
single switch [1], [2] and show that they can be unstable even
for a fixed traffic pattern in a simple network of eight input­
queued switches. Moreover, this result holds regardless of
how the traffic sharing the same port­pair is scheduled at
each switch.
On the positive side we present a protocol, Longest­
in­Network, that is stable in networks of input­queued
switches. This result holds even if the traffic pattern is al­
lowed to change over time.
I. INTRODUCTION

Source: Andrews, Matthew - Mathematics of Networks and Systems, Mathematical Sciences Research Center, Bell Laboratories

Collections: Mathematics; Computer Technologies and Information Sciences