A Network Emulator to Support the Development
of Adaptive Applications
Nigel Davies, Gordon S. Blair, Keith Cheverst and Adrian Friday
Distributed Multimedia Research Group,
Department of Computing,
Lancaster University,
Bailrigg, Lancaster, LA1 4YR, U.K.
telephone: +44 (0)524 65201
e-mail: nigel, gordon, kc, adrian@comp.lancs.ac.uk
Abstract
Mobile applications must operate in environments in which the network
connectivity, input/output devices, power and contextual information
available to them may all vary. Applications which react to changes in
these parameters in order to ensure continuing service to the user are
termed adaptive applications and have recently emerged as an area of
intense research activity. In this paper we describe the design and
implementation of a network emulator which facilitates research in
this field by allowing applications to be exposed to user controlled
fluctuations in network service. The emulator can be used with any
application which uses UDP and requires only minimal changes to the
application or, it may be used with applications written using the
ANSAware distributed systems platform in which case no changes are
necessary to the application. The design and implementation of the
emulator are described in this paper as our experiences of using the
emulator to model three distinct types of wireless network: GSM, an
analogue cellular service and a simple shared radio channel. The
source code for the emulator is freely available and instructions on
obtaining the code are also included.
Download the full text of this paper in
ASCII (35,429 bytes) and
POSTSCRIPT (158,875 bytes) form.
To Become a USENIX Member, please see our
Membership Information.