|Haibo Wang||TsingHua University, P.R. China|
|Jilong Wang||Tsinghua University, P.R. China|
|Weizhen Dang||Tsinghua University, P.R. China|
|Jingan Xue||Tsinghua University, P.R. China|
|Fenghua Li||Tsinghua University, P.R. China|
Dynamic Host Configuration Protocol (DHCP) is widely used to dynamically assign IP addresses. However, due to little knowledge on the behavior and performance of DHCP, it is challenging to configure a proper lease time in complicated wireless network. In this paper, we conduct the largest known measurement on the behavior and performance of DHCP based on the wireless network of T University (TWLAN). TWLAN has more than 59,000 users, 10,000 wireless access points and 130,000 IP addresses. We find the performance of DHCP is far from satisfactory: (1) The non-authenticated devices lead to a waste of 25% of IP addresses at the rush hour. (2) A device does not generate traffic for 67% of the lease time on average. Meanwhile, we find devices of different locations and operating systems show diverse online patterns. A unified lease time setting could result in an inefficient utilization of addresses. To address the problems, taking account of authentication information and device online patterns, we propose a new leasing strategy. The results show it reduces the number of assigned addresses by 24% and reduces the time during which an IP address is occupied by 17% without significantly increasing the DHCP server load.