On the Fairness of Transport Protocols in a Multi-Path Environment

In: Proceedings of the IEEE International Conference on Communications (ICC 2012)
Buchaufsatz / Kapitel / Fach: Informatik
Zentrale wissenschaftliche Einrichtungen » Institut für Experimentelle Mathematik (IEM) Essen
Today, a steadily growing number of devices contains
multiple network interfaces. For example, nearly all
smartphones are equipped with at least W-LAN as well as
3G/4G interfaces. In consequence, there is a rising demand for
so-called multi-path transfer, which utilizes all of these interfaces
IEEE International Conference on Communications, June 10-15, 2012
simultaneously in order to maximize the payload throughput
of applications. Currently, this so-called multi-path transfer is
very actively discussed by the IETF, in form of the Multi-Path
TCP (MPTCP) extension for TCP as well as the Concurrent
Multi-path Transfer extension for SCTP (CMT-SCTP). Their
larger-scale deployment in the Internet is expected for the near
A key issue that prevents the standardization of these approaches
is the fairness to concurrent TCP flows. A multipath
transfer should behave “TCP-friendly”, i.e. cause no harm
to the performance of the very widely deployed TCP-based
applications. In this paper, we first extend the notion of “fairness”
from single-path transport to multi-path transport. Furthermore,
we introduce the relevant congestion control approaches in the
IETF context for single-path as well as multi-path transfer. We
simulatively analyze these approaches in a couple of interesting
network configuration scenarios, in order to show their behavior
with special regard to the fairness definitions. Particularly, we
also point out items of further discussion which are the result of the current approaches.
 IEEE International Conference on Communications, June 10-15, 2012