Link Emulation on the Data Link Layer in a Linux-based Future Internet Testbed Environment

In: Proceedings of the 10th International Conference on Networks~(ICN)
(2011), S. 92-98
ISBN: 978-1-61208-002-4
Buchaufsatz / Kapitel / Fach: Informatik
Zentrale wissenschaftliche Einrichtungen » Institut für Experimentelle Mathematik (IEM) Essen
Fakultät für Wirtschaftswissenschaften » Fachgebiet Wirtschaftsinformatik
Protocol design and development is not a straightforward
process. Each approach must be validated for interactions
and side-effects in the existing network environments.
But the Internet itself is not a good test environment, since its
components are not controllable and certain problem situations
(like congestion or error conditions) are difficult to reproduce.
Various testbeds have been built up to fill this gap. Most of these
testbeds also support link emulation, i.e. using software to mimic
the characteristic behaviour of certain kinds of network links
(like bandwidth bottlenecks or error-prone radio transmissions).
The most popular link emulation systems are the Linux-based
NETEM and DUMMYNET, which are e.g. applied on the IP layer
of Planet-Lab and various other testbeds. However, the restriction
to the OSI Network Layer (here: IP) is insufficient to test new
non-IP Future Internet protocols.
In this paper, we first introduce DUMMYNET and NETEM.
After that, we will present our approach of adapting DUMMYNET
for Linux to support link emulation on the Data Link Layer.
Finally, we evaluate the applicability and performance of DUMMYNET
and NETEM for link emulation on the Data Link Layer,
in a Planet-Lab-based testbed environment. Our goal is to outline
the performance and limitations of both approaches in the context
of Planet-Lab-based testbeds, in order to make them applicable
for the evaluation of non-IP Future Internet protocols.1