Buffer Sizing in Wireless Mesh Networks
Kamran Jamshaid, Basem Shihada, Li Xia, and Philip Levis
Published in Proceedings of the 2011 IEEE Eighth International Conference on Mobile Ad-Hoc and Sensor Systems p272-281, October 2011.
We analyze the problem of buffer sizing for TCP flows in 802.11-based Wireless Mesh Networks. Our objective is to maintain high network utilization while providing low queueing delays. The problem is complicated by the time-varying capacity of the wireless channel as well as the random access mechanism of 802.11 MAC protocol. While arbitrarily large buffers can maintain high network utilization, this results in large queueing delays. Such delays may affect TCP stability characteristics, and also increase queueing delays for other flows (including real-time flows) sharing the buffer. In this paper we propose sizing link buffers collectively for a set of nodes within mutual interference range called the 'collision domain'. We aim to provide a buffer just large enough to saturate the available capacity of the bottleneck collision domain that limits the carrying capacity of the network. This neighborhood buffer is distributed over multiple nodes that constitute the network bottleneck; a transmission by any of these nodes fully utilizes the available spectral resource for the duration of the transmission. We show that sizing routing buffers collectively for this bottleneck allows us to have small buffers (as low as 2 - 3 packets) at individual nodes without any significant loss in network utilization. We propose heuristics to determine these buffer sizes in WMNs. Our results show that we can reduce the end-to-end delays by 6× to 10× at the cost of losing roughly 5% of the network capacity achievable with large buffers.
Talk (287KB), Paper (335KB)
BibTeX entry
@inproceedings{jamshaid2011, author = "Kamran Jamshaid and Basem Shihada and Li Xia and Philip Levis", title = "{Buffer Sizing in Wireless Mesh Networks}", booktitle = "{Proceedings of the 2011 IEEE Eighth International Conference on Mobile Ad-Hoc and Sensor Systems p272-281}", year = {2011}, month = {October} }