Ensuring Seamless Handoff in SIGMA

Mobile IP, a IETF standard to handle mobility of Internet hosts has some existing problems like high handover latency, packet loss, inefficient routing etc. To overcome these problems, we designed alternative novel approach called Seamless IP diversity based Generalized Mobility Architecture (SIGMA), which utilizes multihoming and uses a transport layer protocol, Stream Control Transmission Protocol (SCTP). In our previous work, we have achieved a low latency handoff when MN moves between adjacent wireless network. Our analysis of our system showed that Mobile Node (MN) in SIGMA suffers some instability during handoff (i.e.,) MN makes use of multiple interface cards while in the overlapping region of the wireless network, which is due to the in-efficient handoff scheme of SIGMA. This instability can be eliminated by using a efficient handoff scheme, thus enhancing the stability of the SIGMA. So the objective of this paper is to design an efficient handoff scheme for SIGMA to overcome instability. We implemented a handoff scheme (SINHYR-handoff scheme) based on Signal to Noise Ratio (SNR), hysteresis and route cache flushing. We obtained results experimentally, which shows that the instability of SIGMA is avoided, thus enhanced the stability of during SIGMA handoff.