On the performance of Redundant Traffic Elimination in WLANs

Redundant Traffic Elimination (RTE) detects and removes repeated chunks of data across network flows, protocols, and applications, with the purpose of reducing bandwidth usage. In this paper, we explore the effectiveness of RTE in WLAN, compare it to RTE in Ethernet, and investigate specific issues affecting RTE in WLAN. Our results show that applying RTE to WLAN links is promising and can potentially yield high bandwidth savings, although RTE is not as effective in WLAN as in wired networks. However, to exploit the full potential of RTE, it is necessary to deal with specific challenges, such as longer headers, control and management frames, retransmissions, and dropped frames. We find that including parts of MAC headers in RTE can increase overall bandwidth savings by up to 53% in a public WLAN. To handle dropped frames, which can severely compromise the effectiveness of RTE, we make a case for MAC-layer RTE, which detects frame loss at the sender. This preserves 23% more savings than a previous approach. However, frame retransmissions generate additional traffic at MAC layer, which reduces the effectiveness of RTE in general case.