Mobile IP has been developed to handle mobility of Internet hosts at the network layer. Mobile IP, however, suffers from a number of drawbacks such as requirement of infrastructure change, high handover latency, high packet loss rate, and conflict with network security solutions. In this paper, we describe and evaluate the performance of SIGMA, a Seamless IP diversity based Generalized Mobility Architecture. SIGMA utilizes multihoming to achieve a seamless handover of a mobile host, and is designed to solve many of the drawbacks of Mobile IP, including requirement for changes in infrastructure. We first evaluate the signaling cost of SIGMA and compare with that of Hierarchical Mobile IPv6 (an enhancement of Mobile IP) by analytical modeling, followed by comparison of handover performance of SIGMA and Mobile IPv6 enhancements. Criteria for performance evaluation include handover latency, packet loss, throughput, and network friendliness. Our results indicate that in most cases SIGMA has a lower signaling cost than Hierarchical Mobile IPv6. Moreover, for a typical network configuration, SIGMA has a higher handover performance over Mobile IP.

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Abstract-Domain Name System (DNS) can be deployed in the network as a Location Manager (LM) for mobility management. The suitability of Domain Name System (DNS) as an LM can be measured by how successfully it can serve to locate a mobile host. In this paper, we developed an analytical model to measure the performance of DNS as LM for mobility management techniques with IP Diversity support based on success rate which takes into account the radius of the subnet, the residence time of MH in that subnet, latency in the network and the overlapping distance of two neighboring subnets. Our analysis shows that for a reasonable overlapping distance, DNS can serve as an LM with very high success rate even under some high network latency.

Abstract-TCP has been found to perform poorly in the presence of spurious timeouts (ST) caused by delay spikes which are especially more frequent in today's wireless mobile networks than in traditional wired network. Because STs do not frequently occur in wired networks, and are generally considered to represent a transient state, previous research did not consider the effects of ST on the steady state performance of TCP. However, ST is more frequent in wireless mobile environments, and must be considered explicitly to accurately model the steady state sending rate and throughput of TCP. In this paper, we propose an analytical model for the sending rate and throughput of TCP Reno as a function of packet error rate and characteristics of spurious timeouts. The accuracy of the proposed model has been validated against simulation results. The accuracy of the model has also been compared with previous models, and has been found to be more accurate than previous models in the presence of spurious timeouts.

Abstract-The Stream Control Transmission Protocol (SCTP)is being standardized by IETF as a reliable transport protocol to address a number of limitations of TCP. Due to its attractive features such as multi-streaming and multi-homing, SCTP has received much attention from the research community and industry. This paper serves as a tutorial by introducing the main features of SCTP, and discussing the state of the art in SCTP research activities. We also provide a survey on the available products which implement SCTP. Finally, the challenges faced by SCTP research community are identified with a view to stimulating further research.