Dual-Routing with Multiple Radios Handoff in 80211 Wireless Networks

802.11 wireless networks have gained ever greater popularity nowadays. At the same time, wireless modules´ prices have fallen dramatically. In order to support real-time applications such as VoIP in an 802.11 Wireless LAN, an efficient handoff mechanism using multi-radio module is proposed when a mobile client moves from one Access Point to another. In this paper, we present a method of multi-radio module dual-routing mode in hard handoff at network layer unlike current method that is based on soft handoff or traditional break-before-make. We let two wireless cards send data and only one receives data. Since the MAC layer is work, we just handoff at network layer. By the way, modified OSPF routing protocol should be enabled to ensure route can be immediately updated. Real experiments are conducted to show the superiority of our method on seamless handoff.