Shaojian Fu

Signaling cost and performance of SIGMA: A seamless handover scheme for data networks

Department of Technology Education, Korea National University of Education, San 7-1, Darakri, Chongwon-Gun, Chungbuk, 363-791, KoreaSummaryMobile IPhasbeendeveloped to handlemobility of Internet hosts at thenetworklayer.MobileIP(MIP),however,suffers from a number of drawbacks such as requirement of infrastructure change, high handover latency, highpacket loss rate, and conflict with network security solutions. In this paper, we describe and evaluate theperformance of SIGMA, a Seamless IP diversity-based Generalized Mobility Architecture. SIGMA utilizesmultihoming to achieve seamless handover of mobile hosts, and is designed to solve many of the drawbacks ofMIP, including requirement for changes in infrastructure. We first evaluate the signaling cost of SIGMA andcomparewiththatofhierarchicalMobileIPv6(anenhancementofMobileIP)byanalyticalmodeling,followedbycomparison of handover performance of SIGMA and Mobile IPv6 enhancements. Criteria for performanceevaluation include handover latency, packet loss, throughput, and network friendliness. Our results indicatethat in most cases SIGMA has a lower signaling cost than Hierarchical Mobile IPv6. Moreover, for a typicalnetwork configuration,SIGMA hasahigherhandoverperformanceoverMobileIP.Copyright#2005JohnWiley& Sons, Ltd.KEY WORDS: mobile handover; SIGMA; mobile IP; IP diversity; signaling cost1. IntroductionMobile IP (MIP) [1] has been designed to handlemobility of Internet hosts at the network layer tomanage mobile data communication. It allows aTCP connection to remain alive when a mobile host(MH) moves from one point of attachment to another.Several drawbacks exist when using MIP in a mobilecomputing environment, the most important onesidentified to date are high handover latency, highpacket loss rate [2], and requirement for change ininfrastructure. MIP is based on the concept of homeagent (HA) and foreign agent (FA) (which requiresmodificationtoexistingroutersinInternet)forroutingpackets from previous point of attachment to the newone. An MH needs to complete the following foursteps before it can receive forwarded data from theprevious point of attachment: (i) perform layer 2 (L2)handover, (ii) discover the new care of address (CoA),(iii) registering the new CoA with the HA, and (iv)

Architecture and performance of SIGMA: a seamless mobility architecture for data networks

The Internet Engineering Task Force has developed Mobile IP to handle the mobility of Internet hosts at the network layer. Mobile IP, however, suffers from a number of drawbacks such as high handover latency, packet loss, and conflict with network security solutions. We describe and evaluate the performance of SIGMA (seamless IP diversity based generalized mobility architecture). SIGMA utilizes IP diversity to achieve the seamless handover of a mobile host, and is designed to solve many of the drawbacks of Mobile IP. Various aspects of the performance of SIGMA and Mobile IPv6 enhancements have been compared. Criteria for performance evaluation include handover latency, packet loss, throughput, and network friendliness.

SCTP: state of the art in research, products, and technical challenges

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. The 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.

Effect of delay spike on SCTP, TCP Reno, and Eifel in a wireless mobile environment

Eifel has been proposed as a solution to enhance the performance of TCP during delay spikes in a wireless mobile environment. This paper evaluates and compares the performance of SCTP, TCP, and Eifel during delay spikes. We have shown that although Eifel performs better than TCP Reno and SCTP when there are no packet losses, the opposite is true when packets are lost in the presence of delay spikes. Our results also show that a higher link bandwidth does not always increase the data throughput of SCTP, TCP Reno, and Eifel.

SCTP over satellite networks

The stream control transmission protocol (SCTP) has recently been standardized as a new transport layer protocol in the IP suite. In addition to the core features of TCP, SCTP incorporates a number of advanced and unique features which are not available in TCP. The paper investigates the suitability of SCTP for data communications over satellite links. We describe SCTP features that allow SCTP to utilize the bandwidth of satellite networks better, while at the same time avoiding congestion collapse in a shared network. Finally, we provide recommendations on the use of SCTP over satellite networks.

Handover latency comparison of SIGMA, FMIPv6, HMIPv6, FHMIPv6

In our earlier study, we proposed SIGMA, a seamless IP diversity based generalized mobility architecture. SIGMA utilizes IP diversity to achieve a seamless handover of a mobile host, and is designed to solve many of the drawbacks of mobile IP. In this paper, we compare the handover latency of SIGMA and recent MIPv6 enhancements, namely, FMIPv6, HMIPv6, and FHMIPv6. Various parameters are considered such as layer 2 handover/setup latency, IP address resolution latency, layer 2 beacon period, and mobile host moving speed. Our results show that SIGMA handover latency is insensitive to layer 2 setup latency, IP address resolution latency and beacon periods. Moreover, SIGMA is able to seamlessly handle relatively high speed movement of mobile host

Performance modeling of SCTP multihoming

Stream control transmission protocol (SCTP) is a new transport layer protocol which is being standardized by IETF. Multi-homing, one of the most attractive features of SCTP, makes it competitive in high-availability and mobile environments. In this paper, we propose an analytical model for evaluating the performance of SCTP multi-homing. The proposed model has been validated against and found to agree well with simulation results.

Improving end-to-end throughput of Mobile IP using SCTP

Mobile IP is the IETF-proposed standard to offer seamless mobile computing. A new transport layer protocol, called stream control transmission protocol (SCTP), has recently been accepted by IETF as a proposed standard to address a number of TCP limitations. Most of the previous research on end-to-end throughput over Mobile IP has been carried out on TCP-Reno. Both TCP and SCTP can use selective acknowledgment (SACK) for error recovery. The effect of SCTP on the improvement of throughput during handovers in Mobile IP is analyzed. We show that SCTP has a better performance than TCP-Reno and TCP-SACK due to its support for unlimited number of SACK blocks. We conclude that SCTP can be used to improve the end-to-end throughput when the bottleneck link bandwidth is low.

Performance of DNS as location manager for wireless systems in IP networks

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.

Performance of DNS as location manager

Domain name system (DNS) maps domain names to IP addresses in the Internet. DNS can, however, be used as a location manager (LM) for mobility management in wireless mobile networks. The suitability and performance of DNS as a LM for locating mobile hosts (MH) has not been studied in the past. In this paper, we develop an analytical model to measure the performance of DNS as LM for IP diversity based mobility management. We have used success rate, which takes into account the radius of the subnet, the residence time of a MH in a subnet, velocity of MH, network latency, DNS processing delay and the overlapping distance between two neighboring subnets as performance measures. Our analysis shows that for a reasonable overlap between cells, DNS can serve as a LM with very high success rate even under high network latency