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IEEE 802.11-based wireless local area networks (WLANs) have been set up in many public places in recent years. It provides convenient network connectivity to mobile nodes (MNs) and allows users moving from one wireless network to another. With mobility protocol support, such as Mobile IPv6 (MIPv6), people can roam across wireless IP subnets without loss of network-layer connectivity. However, the handover latency may make users uncomfortable in MIPv6. To support seamless handover, an enhanced MIPv6 scheme, Fast Handovers for Mobile IPv6 (FMIPv6) [1], was been proposed. In order to further reduce the handover latency, integration IEEE 802.11 and MIPv6 is necessary. Unfortunately, when integrating the IEEE 802.11-based standard with FMIPv6, FMIPv6 always fails to perform predictive handover procedure and results in reactive handover. It is because of the protocol nature of IEEE 802.11 and the weak relationship between IEEE 802.11 and FMIPv6. Furthermore, a MN can not receive packets destined to it as it sends the Fast Binding Update (FBU) to the original access router (OAR). This would cause unnecessary packet loss and make the predictive handover have more packet loss then reactive. Those issues will cause quality of services degradation and make real-time application unreachable. In this paper, a low-latency MIPv6 handover scheme will be proposed. It is an FMIPv6-based scheme, which is based on an active-scan scheme link layer assistance. It has the advantage of FMIPv6 and can reduce the unnecessary packet loss when the handover occurs. Also, with the active scheme assistance, it can avoid the longest phase that IEEE 802.11 will enter, and can lower the handover latency.

Keywords: handover, IEEE 802.11, FMIPv6, latency, wireless

Retrieve PDF document (200901_13.pdf)

Received March 12, 2007; revised May 14, 2007; accepted May 23, 2007.
Communicated by Makoto Takizawa.