Fast IP Handoff Support for VoIP and Multimedia Applications in 802.11

Wireless LANs (WLANs) have edged into numerous mobile and wireless users ’ daily experience worldwide as a mainstream connectivity solution for a broad range of applications. Even though WLANs offer very high channel bandwidth, they show long network-layer handoff latency. This is a restraining factor for mobile clients using interactive multimedia applications such as voice over IP (VoIP) or video streaming. This paper presents an 802.11-dependent fast IP handoff method which quickly restores IP connectivity for mobile clients running next generation WLAN applications such as Voice over WLANs (VoWLAN). This method outperforms other existing proposed IP mobility solutions in 802.11 WLANs as verified from real performance testing, while introduces insignificant compulsory additions to the existing 802.11 wireless LAN framework. 1

Engineering and Informatics,

Abstract: This paper presents an effective and simple solution to the problem of Layer 3 (L3) handover in IEEE 802.11 wireless LANs (WLANs), so as to extend the IP mobility area of 802.11 wireless Stations (STAs). The IEEE 802.11f Inter-Access Point Protocol (IAPP), handles the Layer 2 (L2) mobility of STAs during L2 (intra-network) handovers, and offers IP connectivity via L2 specific methods. Instead of using a different protocol for the L3 mobility management of STAs, such as Mobile IP (MIP) [4] or a MIP-variant, the IAPP protocol is extended so as to also support the inter-network (L3) movements of 802.11 STAs. The proposed IAPP-based mechanism supports host mobility and offers substantial uninterrupted wireless IPconnectivity, even after L3 movements. The cornerstones of this mechanism are the zero-delay IP movement detection and the zero over-the-air IP signaling during IP handover establishment, which lead to seamless (very fast) and smooth IP handoffs. This fast IP-handoff method is especially suitable to 802.11 systems, as it has better performance than traditional MIP-based methods (shorter handover delays, near zero packet loss), while makes IP roaming transparent to the mobile STAs