We consider an IEEE 802.11 based wireless LAN where an access point is used to connect a fixed number of users to the web or to a shared file system. Users alternate between activity periods (corresponding to the download of a file) and idle periods (corresponding to think times). We? first consider the interaction of TCP with the IEEE 802.11 MAC protocol, and get approximate expressions for the TCP throughput in presence of $n_c$ competing persistent connections. This result is then used to develop a queueing model, which is used to determine the mean session delay in presence of short\textendashlived flows. The analysis also accounts for the TCP delayed ACK option. Comparison with simulation outcomes is provided, validating the model and providing guidelines for network designers. A particular emphasis is devoted to the impact of the advertised window size; in particular, it is proved that setting it to a small value leads to insensitivity of mean file? transfer times to the file size distribution.<br />
A Queueing Model for HTTP Traffic over IEEE 802.11 WLANs
Daniele Miorandi;
2004-01-01
Abstract
We consider an IEEE 802.11 based wireless LAN where an access point is used to connect a fixed number of users to the web or to a shared file system. Users alternate between activity periods (corresponding to the download of a file) and idle periods (corresponding to think times). We? first consider the interaction of TCP with the IEEE 802.11 MAC protocol, and get approximate expressions for the TCP throughput in presence of $n_c$ competing persistent connections. This result is then used to develop a queueing model, which is used to determine the mean session delay in presence of short\textendashlived flows. The analysis also accounts for the TCP delayed ACK option. Comparison with simulation outcomes is provided, validating the model and providing guidelines for network designers. A particular emphasis is devoted to the impact of the advertised window size; in particular, it is proved that setting it to a small value leads to insensitivity of mean file? transfer times to the file size distribution.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
