End-to-end versus explicit feedback measurement in 802.11 networks

Higher layer protocols in wireless networks need to dynamically adapt to observed network response. The common approach is that each session employs end-to-end monitoring to estimate quantities of interest, like delay, delay jitter and available bandwidth. A less conventional approach is to employ lower layer explicit feedback mechanisms in place or in aid of end-to-end efforts. Available bandwidth measurements are known to follow multi-modal distributions and therefore are especially difficult to measure and filter, even in wired networks. In 802.11-based multi-hop networks obtaining usable end-to-end measurements is questionable. They are affected by a combination of a large number of transient variables due to the virtual carrier sense, head of line problems on each link and mobility. Motivated by this, we are developing a network explicit feedback mechanism. Our study of this accurate network feedback architecture aids in the cost/benefit analysis of an important trade-off: deployment of network support mechanisms for transports and QoS, versus the simple, scalable and easily deployable end-to-end solution. We test our solution in: (i) multimedia adaptation and (ii) measurement based call admission. Loss rates of end-to-end adaptive video and audio connections have been more than 4 times higher than in the network feedback case. A simple call admission strategy has also proved very effective using the feedback. In our experiments it led the network to a maximal performance and stable operating point.

[1]  J. Oksman,et al.  Filtrage des signaux à échantillonnage non uniforme Digital filters for non-uniformly sampled signals , 2001 .

[2]  Charles E. Perkins,et al.  Ad-hoc on-demand distance vector routing , 1999, Proceedings WMCSA'99. Second IEEE Workshop on Mobile Computing Systems and Applications.

[3]  Vaduvur Bharghavan,et al.  Achieving MAC layer fairness in wireless packet networks , 2000, MobiCom '00.

[4]  Mario Gerla,et al.  GloMoSim: A Scalable Network Simulation Environment , 2002 .

[5]  Mark Crovella,et al.  Server selection using dynamic path characterization in wide-area networks , 1997, Proceedings of INFOCOM '97.

[6]  Henning Schulzrinne,et al.  RTP: A Transport Protocol for Real-Time Applications , 1996, RFC.

[7]  Parameswaran Ramanathan,et al.  What do packet dispersion techniques measure? , 2001, Proceedings IEEE INFOCOM 2001. Conference on Computer Communications. Twentieth Annual Joint Conference of the IEEE Computer and Communications Society (Cat. No.01CH37213).

[8]  Vern Paxson,et al.  End-to-end Internet packet dynamics , 1997, SIGCOMM '97.

[9]  Mary Baker,et al.  Measuring bandwidth , 1999, IEEE INFOCOM '99. Conference on Computer Communications. Proceedings. Eighteenth Annual Joint Conference of the IEEE Computer and Communications Societies. The Future is Now (Cat. No.99CH36320).

[10]  M. Gerla,et al.  On fairness and efficiency of adaptive audio application layers for multihop wireless networks , 1999, 1999 IEEE International Workshop on Mobile Multimedia Communications (MoMuC'99) (Cat. No.99EX384).

[11]  Allen H. Levesque,et al.  Quality of service support in mobile ad-hoc IP networks , 1999, MILCOM 1999. IEEE Military Communications. Conference Proceedings (Cat. No.99CH36341).

[12]  Sung-Ju Lee,et al.  Permissible throughput network feedback for adaptive multimedia in AODV MANETs , 2001, ICC 2001. IEEE International Conference on Communications. Conference Record (Cat. No.01CH37240).

[13]  Jeong Geun Kim,et al.  Investigation of the IEEE 802.11 medium access control (MAC) sublayer functions , 1997, Proceedings of INFOCOM '97.