TKN - Telecommunication Networks Group ... - of TKN - TU Berlin
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<strong>TKN</strong> - <strong>Telecommunication</strong> <strong>Networks</strong> <strong>Group</strong> - Pr<strong>of</strong>. Wolisz<br />
An IEEE 802.11e EDCA and CFB Simulation Model for ns-2<br />
Overview<br />
Sven Wiethölter, Christian Hoene<br />
The IEEE 802.11 standard supports two MAC mechanisms, the Distributed Coordination Function<br />
(DCF) and the Point Coordination Function (PCF). These mechanisms are considered to be<br />
insufficient for achieving a reasonable quality in scenarios with high background load. Thus, QoS<br />
enhancements are vividly studied and evaluated. The QoS enhancements developed by the IEEE<br />
802.11e WG have been under design for several years. The amendment to the 802.11 standard was<br />
finally approved and published in November 2005. Basically, IEEE 802.11e introduces two additional<br />
MAC modes: the Enhanced Distributed Channel Access (EDCA) and the HCF Controlled Channel<br />
Access (HCCA), which have been derived from their earlier versions EDCF (Enhanced Distributed<br />
Channel Function) and HCF (Hybrid Coordination Function) <strong>of</strong> previous drafts.<br />
On this web page, we present an open-source, verified simulation model <strong>of</strong> IEEE 802.11e's EDCF /<br />
EDCA mode for the network simulator (ns-2.26 / ns-2.28). We verified the model by comparing it with<br />
previous results, which have been published by Stefan Mangold et al. The 802.11e EDCA model is<br />
an easy adaptable, modular and documented solution. We added the contention free bursting (CFB)<br />
to our model, which allows the transmission <strong>of</strong> a train <strong>of</strong> small packets without intermediate<br />
contention. Sometimes CFB is also denoted as TXOP bursting.<br />
Our simulation model is based on the ns-802.11 DCF model. Actually, it extends the wireless and<br />
mobility code, which has been developed in the CMU Monarch project. We removed a couple <strong>of</strong><br />
bugs in the legacy model and expanded the queues as well as the MAC with its timer model into a<br />
multi-dimensional MAC. The bug description, a short introduction into the model implementation and<br />
its verification can be found here. Additionally, we provide a patch for the legacy 802.11 model <strong>of</strong> ns-<br />
2.28 that can be downloaded here. It includes all fixes to the bugs described in the technical report<br />
(<strong>TKN</strong>-03-019).<br />
The EDCA model lacks the HCCA, the block ACK mechanism, any management mechanisms like<br />
Association/Reassociation, Authentication/Deauthentication. In addition, no superframe structure<br />
with Beacon frames and no power-saving methods are supported.<br />
The RTS/CTS mechanism, which is included in the legacy ns-802.11 model, has never been tested<br />
and verified. Therefore we do not recommend to use RTS/CTS without reviewing the code in detail.<br />
We recommend to use the EDCA model for ns-2.28, since the older version is not compliant to the<br />
final 802.11e amendment. An installation instruction is included in the readme file.<br />
Download<br />
● Sourceforge project web page for EDCA model (includes CVS, bug reports and support)<br />
● Patch for 802.11 model (ns-2.28)<br />
Publications<br />
http://www.tkn.tu-berlin.de/research/802.11e_ns2/ (1 von 3)08.08.2011 17:50:04 Uhr<br />
❍ Technical Report <strong>TKN</strong>-03-019, Sven Wiethölter, Christian Hoene, "Design and<br />
Verification <strong>of</strong> an IEEE 802.11e EDCF Simulation Model in ns-2.26",<br />
<strong>Telecommunication</strong> <strong>Networks</strong> <strong>Group</strong>, Technische Universität <strong>Berlin</strong>, November 2003.<br />
(PDF)
<strong>TKN</strong> - <strong>Telecommunication</strong> <strong>Networks</strong> <strong>Group</strong> - Pr<strong>of</strong>. Wolisz<br />
http://www.tkn.tu-berlin.de/research/802.11e_ns2/ (2 von 3)08.08.2011 17:50:04 Uhr<br />
❍ Technical Report <strong>TKN</strong>-04-11, Sven Wiethölter, Christian Hoene, Adam Wolisz,<br />
"Perceptual Quality <strong>of</strong> Internet Telephony over IEEE 802.11e Supporting Enhanced<br />
DCF and Contention Free Bursting", <strong>Telecommunication</strong> <strong>Networks</strong> <strong>Group</strong>, Technische<br />
Universität <strong>Berlin</strong>, September 2004. (PDF)<br />
❍ Technical Report <strong>TKN</strong>-06-003, Sven Wiethölter, M. Emmelmann, Christian Hoene,<br />
Adam Wolisz "<strong>TKN</strong> EDCA Model for ns-2", <strong>Telecommunication</strong> <strong>Networks</strong> <strong>Group</strong>,<br />
Technische Universität <strong>Berlin</strong>, June 2006. (PDF)<br />
Publications refering to this model<br />
❍ Alessandro Andreadis, Giuliano Benelli, and Riccardo Zambon, „Evaluation <strong>of</strong> QoS<br />
Support for Multimedia Traffics in IEEE 802.11e “, in Proc. <strong>of</strong> S<strong>of</strong>tCOM, Split-Dubrovnik,<br />
Croatia, September 2006.<br />
❍ M. Thottan and M. C. Weigle, „Impact <strong>of</strong> 802.11e EDCA on Mixed TCP-based<br />
Applications“, in Proc. <strong>of</strong> the International Wireless Internet Conference (WICON),<br />
Boston, August 2006.<br />
❍ A. Banchs and L. Vollero, „Throughput analysis and optimal configuration <strong>of</strong> 802.11e<br />
EDCA“, Computer <strong>Networks</strong>, Volume 50, Issue 11, pp. 1749-1768, August 2006.<br />
❍ Yi-Wen Lan, Jui-Hung Yeh, Jyh-Cheng Chen, and Zi-Tsan Chou, „Performance<br />
Enhancement <strong>of</strong> IEEE 802.11e EDCA by Contention Adaption“, VTC 2005-Spring,<br />
Stockholm, Sweden.<br />
❍ C. Bettstetter, C. Preh<strong>of</strong>er, and A. Wolisz, "A Performance Comparison <strong>of</strong> QoS<br />
Approaches for Ad Hoc <strong>Networks</strong>: 802.11e versus Distributed Resource Allocation", In<br />
Proc. <strong>of</strong> European Wireless 2005, Nicosia, Cyprus, April 2005.<br />
❍ Carlos Calafate, Pietro Manzoni, Manuel Malumbres, "Supporting s<strong>of</strong>t real-time services<br />
in MANETs using distributed admission control and IEEE 802.11e technology", 10th<br />
IEEE Symposium on Computers and Communications (ISCC 2005), June 27-30, 2005,<br />
La Manga del Mar Menor, Cartagena, Spain.<br />
❍ Carlos T. Calafate, Pietro Manzoni, Manuel P. Malumbres. "On the Interaction Between<br />
IEEE 802.11e and Routing Protocols in Mobile Ad-Hoc <strong>Networks</strong>," 13th Euromicro<br />
Conference on Parallel, Distributed and Network-Based Processing (PDP'05), pp. 110-<br />
117, 2005.<br />
❍ L. Scalia, I. Tinnirello, “Differentiation mechanisms for heterogeneous traffic integration<br />
in IEEE 802.11 networks," BroadWin 2004, October 2004, San Jose, USA.<br />
❍ Carlos T. Calafate, M. P. Malumbres, Pietro Manzoni, "Assessing the effectiveness <strong>of</strong><br />
IEEE 802.11e in multi-hop network environments", 12th Annual Meeting <strong>of</strong> the IEEE /<br />
ACM International Symposium on Modeling, Analysis, and Simulation <strong>of</strong> Computer and<br />
<strong>Telecommunication</strong> Systems (MASCOTS), October 5-7 2004, Volendam The<br />
Netherlands.<br />
❍ Douglas J. Leith, Peter Clifford: Using the 802.11e EDCF to Achieve TCP Upload<br />
Fairness over WLAN Links. WiOpt 2005: 109-118<br />
❍ Ken Duffy, David Malone and Douglas J. Leith, „Modeling the 802.11 distributed<br />
coordination function in non-saturated conditions,“ to appear IEEE Communications
<strong>TKN</strong> - <strong>Telecommunication</strong> <strong>Networks</strong> <strong>Group</strong> - Pr<strong>of</strong>. Wolisz<br />
Letters (2005).<br />
❍ Lu Yang, “P-HCCA: A New Scheme for Real-time Traffic with QoS in IEEE 802.11e<br />
Based <strong>Networks</strong>,” APAN Network Research Workshop 2004 .<br />
❍ Andrea Alfieri, „Simulazione del modello Enhanced Distributed Coordination Function<br />
(EDCF) tramite NS-2“, Thesis, UNIVERSITA’ DEGLI S<strong>TU</strong>DI DI PARMA, Italy, 2005.<br />
Contact<br />
If you use our model, please send us a brief email with a reference to your publication.<br />
If you have any questions please mail them to the sourceforge.net or the ns-2 mailing list. We<br />
are sorry to announce that we are not going to answer any emails regarding 802.11e anymore.<br />
❍ Sourceforge IEEE802.11e ns/2 mailing lists<br />
❍ The ns/2 mailing lists<br />
Related Links<br />
http://www.tkn.tu-berlin.de/research/802.11e_ns2/ (3 von 3)08.08.2011 17:50:04 Uhr<br />
❍ IEEE 802.11 Working <strong>Group</strong><br />
❍ IEEE 802.11e HCCA simulation using the Network Simulator 2 by the Computer<br />
Networking <strong>Group</strong> <strong>of</strong> the University <strong>of</strong> Pisa<br />
❍ Stanford's 802.11e implementation for ns/2<br />
❍ Qiang Ni's EDCF/HCF implementations for ns/2<br />
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