A Dense Wireless LAN Case Study

Abstract

While usage and trends for campus wireless LANs have been extensively studied through various deployment instances, very few studies have been done to study short term deployments of wireless LANs, such as those provisioned at the conference venues. We conduct a detailed study of a dense wireless LAN consisting of $82$ access points (APs) deployed to serve over 5000 SuperComputing 2004 users. By studying traffic generated by all layers of the TCP/IP protocol stack, we make several observations that differ from those made by the previous wireless LAN studies. In particular, we find that: applications lacking congestion control were more popular than previously reported, channel error rates were higher, a very high percentage of broadcast traffic was present, and that the client mobility was higher than what was previously observed. The two novel features of our custom traffic analyzer that made these observations possible are: 1) it looks at traffic both from the perspective of the total number of bytes, as well as the total number of packets and 2) it conducts a bi-directional traffic analysis from wireless clients to APs and from APs to clients.