Nowadays in mobile and wireless networks environment, Mobile IP is the preferred standard in supporting IP mobility among several standards. However, several problems still need to be solved. One of them is the triangle routing problem. Although drafts have been proposed by the IETF (Internet Engineering Task Force) for solving this problem, the proposed solution can not be achieved unless the draft of the Mobile IP route optimization method becomes a typical standard of the Mobile IP. In this paper, we present an extended routing agent architecture to solve this problem. The Middle Mobility Agent (MMA) in the proposed architecture can intercept datagrams earlier and determine to tunnel the incoming packet or not than the MH¡¦s original home agent. This architecture can solve the triangle routing problem by reducing packet¡¦s routing length. An analytical model and a simulation environment were set up to evaluate and measure the packet¡¦s routing length and delay time of proposed architecture. The evaluation and simulation results demonstrate that the proposed method can reduce the routing length, delay time and solve the triangle routing problem.

Today¡¦s mobile IP supports host mobility by dynamic changing IP addresses while the mobile host roaming in the Internet. However, There still exists performance problems during handoffs, such as packet loss, throughput degradation, and so on. In this Thesis, we propose a mechanism to reduce packet loss during handoff. The packet buffering mechanism at a home agent is initiated by mobile hosts when the signal-to-noise ratio of the wireless link falls below some predefined threshold. Once the handoff has completed, the home agent immediately delivers the first packet in the buffer to the mobile host. The home agent then clears the buffered packets already received by the mobile host through the returned ACK such that no further duplicate packets are sent out. In addition, we propose a route-selection policy to reduce end-to-end transmission delay by sending out probe packets along the paths. For the purpose of demonstration, we implement the mechanism on Linux platform. Through the measurements from the experiment, we have shown that the proposed mechanism can improve the throughput and solve the packet retransmission problem while handoffs.

[pt] Em redes IP com mobilidade, uma conexão de transporte estabelecida com um dispositivo móvel pode ser interrompida devido a uma possível troca do endereço IP ocasionada por uma mudança de rede. O período compreendido entre o instante em que dispositivo percebe que está mudando de rede - momento em que se inicia o processo de alteração de seu endereçamento IP - até o momento do restabelecimento de suas conexões com outros dispositivos chama-se período de handoff, e sua duração é denominada latência do handoff. Existem especificações de protocolos que permitem que os nós móveis continuem acessíveis enquanto se movimentam na rede IPv6, como o MIPv6 (Mobility for IPv6). Porém, mesmo com a utilização do MIPv6, durante o período de handoff, pacotes trocados com o dispositivo móvel que se deslocou podem sofrer atrasos maiores do que o desejado ou até mesmo serem perdidos. Esse efeito acaba por diminuir a qualidade da comunicação, especialmente quando se está lidando com dados multimídia. O foco do presente trabalho é a implementação do protocolo Host Identity Protocol (HIP) numa ferramenta de simulação e a avaliação desse protocolo com o objetivo de estabelecer, de maneira quantitativa, o impacto do rompimento e restabelecimento da comunicação em ambientes móveis. A proposta do protocolo HIP é garantir a mobilidade usando uma nova identidade para os hosts de forma independente do endereço IP. São estudados, por meio de simulação, a latência e a perda de pacotes durante o handoff do protocolo HIP com o intuito de fundamentar novas investigações. / [en] In mobile IP networks, a connection of transport established with a mobile device may be interrupted due to a possible exchange of IP addresses caused by a change of network. The period between the moment when device realizes that the network is changing - time in which begins the process of changing its IP address - until the moment that it restores all connections with other devices is called period of handoff, and this period is called the latency of handoff . Some protocols specifications allow us to remain accessible while mobile move in IPv6 network, as the MIPv6 (Mobility for IPv6). But even with the use of MIPv6, during the handoff, exchanged packages with the mobile device could be delayed more than desired or even be lost. This effect diminish the quality of communication, especially when it is dealing with multimedia data. The focus of this work is the implementation of the Protocol Host Identity Protocol (HIP) in a tool for simulation to evaluate the protocol with the goal of establishing, quantitative way, the impact of disruption and restoration of communication in mobile environments. The proposed protocol ensures the mobility using a new identity for the hosts that is independent IP address. The latency and loss of packages are studied, by simulation, during the handoff of HIP protocol in order to justify further investigation.

Seamless communication is becoming the main aspect for the next generation of the mobile and wireless networks. Roaming among multiple wireless access networks connected together through one IP core makes the mobility support for the internet is very critical and more important research topics nowadays. Mobile IP is one of the most successful solutions for the mobility support in the IP based networks, but it has poor performance in term of handover delay. Many improvements have been done to reduce the handover delay, which result in two new standards: the Hierarchical MIP (HMIP) and the Fast MIP (FMIP), but the delay still does not match the seamless handover requirements. Finally Seamless MIP (S-MIP) has been suggested by many work groups, which combine between an intelligent handover algorithm and a movement tracking scheme. In This thesis, we show the handover delay reduction approaches, specifically the Seamless Mobile IP. The thesis studies the effects of the S-MIP in the handover delay and the network performance as well. A simulation study takes place to compare between the standard MIP and the new suggested S-MIP protocol in term of handover delay, packet loss and bandwidth requirement. The thesis concludes with the analyzing of the simulation results, evaluating the S-MIP performance and finally gives some suggestions for the future work. / 0046704623257

This thesis consists of theoretical and practical parts. The theoretical part contains an analysis of the problems of wireless networkssolutions individual standards and methodologies to ensure quality of service. In the practical part using the OPNET Modeler, a number of different simulation models and their evaluation. It is a model of individual standards, support mobility and interference effects on quality of service.

This report is the result of a masters degree project conducted at the Department of Teleinformatics at the Royal Institute of Technology starting from the autumn 1996. The area investigated is the Mobile Internet Protocol, especially its implementation under Windows NT environment. Network driver writing under Windows NT was practised. Recent development in improving Mobile IP protocol to support micro-mobility have also been investigated.

Nomadic computing aims to be a leading short term revolution in the Internet, however to succeed in this the infrastructure, the protocols, the handoff mechanisms have to be designed and implemented to provide mobile computing with both reliability and transparency. A good deal of the work is addressed by mobile IP itself, but addressing wireless diversity is perhaps the most important next step. Many different wireless technologies are available; while one technology might provide wide coverage, another provides higher bandwidth, but can only be deployed locally, even uni-directional ad-hoc links can be used to carry IP traffic. To take full advantage of the potential infrastructure, a mobile device, with multiple network interfaces, should be able to dynamically switch from one link technology to another; hopefully totally transparently to the user. Moreover, having multiple interfaces allows the device to choose, each time a new connection is established, which interface to select to route the datagrams through, based on the type of service desired. In this thesis a possible solution is presented, involving both vertical handoff optimization and policy management. Our testing device is the the SmartBadge v4, provided with a GPRS link and a 802.11b WLAN interface. / Nomadic Computing har för avsikt att revolutionera dagens Internet tillämpningar. För att lyckas måste dock infrastrukturen, IT protokollen och handoff procedurer utformas och implementeras med intentionen att förse mobilt dataöverföring med både driftsäkerhet och autonoma processer. En stor del av de nödvändiga förutsättningarna är tillgängliga tack vare Mobile IP, men mångfalden inom de befintliga Wireless teknologierna utgör fortfarande ett problem. Det stora antalet disponibla Wireless tekniker varierar från teknologierer som förser användaren med en stor täckningsgrad, till sådana som förser användaren med högre bandbredd, begränsad till lokala anv ändningområden. Även Uni-directional ad-hoc links kan läggas i denna lista av mångfald. För att förverkliga fördelarna med den tänkta infrastrukturen fullt ut måste den mobila enheten kunna utföra omkopplingar från den ena wireless teknologin till den andra, med syftet att vara osynlig för användaren. Utöver detta är det meningen att en apparat med många anslutningar ska kunna välja den anslutning som passar bäst, var gång en ny koppling ska göras, beroende på den tjänst som efterfrågas. Det här examensarbetet presenterar en möjlig lösning, som utnyttjar både Vertical Handoff optimering och Policy Management. Prototyp-enheten vi anv änder oss av för att genomföra undersökningen är Smart Badge v4, utrustad med GPRS och 802.11b Wireless LAN anslutningar.

As the coverage of modern wireless technologies expands, today’s mobile phones and PDAs often have a range of heterogeneous networks to which they may connect. It would benefit mobile applications to use the network which best corresponds to its need. However, making the handovers between networks transparent to allow communication sessions to survive is not trivial as the TCP/IP suite, used by most networking applications today, was initially not designed with mobility in mind. A Vinnova founded research project at Saab (together with associates1) has found that it could prove advantageous to monitor network quality together with the application’s needs and make intelligent decisions regarding what network to use. An algorithm for network classification and evaluation has been proposed. This thesis examined prerequisites and methods for implementing adaptive network connectivity through transparent handovers for mobile devices, resulting in a tentative model to demonstrate the mentioned research results. The prototype, implemented as a user space middleware, utilizes UDP encapsulation and a per-packet basis link evaluation, resulting in small overhead and fast context adaptation. Link monitoring ensures that server and clients are constantly updated about network quality and availability. The prototype yielded transparent handovers between networks, with short handover delays, at the cost of reduced performance for fast networks. 1 Blekinge Institute of Technology, Swedish National Testing and Research Institute, and SwedishRoad Administration / Täckningen av trådlösa nätverk ökar konstant, och dagens mobiltelefoner och handdatorer har ofta ett antal olika nätverk de kan ansluta till. Det skulle vara fördelaktigt för mobila applikationer att använda det nätverk som bäst passar dess behov. Att göra övergångarna mellan dessa nätverk transparenta så att pågående kommmunikationssessioner kan fortgå är dock inte helt trivialt, då TCP/IP protokollen från början inte var tänkta för mobila enheter. Ett av Vinnova finansierat forskningsprojekt utfört på Saab med flera1 har undersökt möjligheterna att övervaka kvaliteten på olika trådlösa nätverk samt kraven från applikationerna, och med detta som grund utföra intelligenta beslut om vilket nätverk som ska utnyttjas. En algoritm för att utföra dessa beslut har också föreslagits. Detta examensarbete undersökte möjligheterna för att implementera adaptiv nätverksroaming genom transparenta övergångar för mobila enheter, och resulterade i en demonstrator, som även kan visa resultaten från den nämnda forskningen. Prototypen, implementerad som en "middleware", använder UDP tunnling och en per-paket nätverksutvärdering, vilket resulterade i liten overhead och snabb anpassning till nya kommunikationssituationer. En länkövervakare såg till att server och klienter alltid var uppdaterade om kvaliteten och tillgängligheten av olika nätverk. Prototypen gav totalt transparenta övergångar mellan nätverk med relativt korta fördröjningar, med nackdelen av viss reducerad prestanda för snabba nätverk. 1 Blekinges Tekniska Högskola, Sveriges Provnings – och Forskningsinstitut, samt Vägverket

With the increasing use of electronic devices, the need for affordable wireless services specifically context-aware services, in a so-called Personal Area Network (PAN) is becoming an area with significant potential. Service discovery is a basic function. Even though a number of service discovery protocols have been implemented, a specific protocol for a PAN environment may need to be developed, as the characteristics of a PANs differ from other networking environments. Thus, the specific requirements for service discovery from a PAN perspective were studied. Methods for service discovery will be described that take into account both local and remote services. These methods will then be evaluated in a SIP telephony infrastructure to decide where a call should be delivered. The location of a person is done by using the implemented service discovery. / Med en ökad användning av elektroniska enheter blir behovet av trådlösa tjänster, speciellt context-medvetna tjänster i så kallade Personal Area Network (PAN), ett område med betydlig potential. Service Discovery är en grundläggande funktion. Även om flera service discovery protocols har implementerats finns det behov av ett specifikt protokoll för PAN-miljöer då egenskaperna hos ett PAN skiljer sig från andra nätverksmiljöer. Således studerades de specifika krav för service discovery från ett PAN perspektiv. Metoder för service discovery kommer att ta med i beräkningen båda lokala och avlägna tjänster. Dessa metoder utvärderas i en SIP telephony infrastructure för att avgöra var en påringning ska levereras. Lokalisering av en användare sker genom det implementerade service discovery-protokollet.

No / In this paper, the requirements for personal environments mobility are addressed from terminal and network perspectives. Practical mobility and Quality of Service (QoS) aware solutions are proposed for a heterogeneous network, comprising of satellite and terrestrial access networks connected to an IP core network. The aim, in adopting a heterogeneous environment, is to provide global, seamless service coverage to a specific area, allowing access to services independently of location. An important assumption is that nomadic user terminals attached to a particular segment should be able to exchange information with any other terminal connected to the network. This is to ensure transparency of device technology. Different communication scenarios are investigated in support of IPv4 and IPv6 operating on user platforms and over access segments. The heterogeneous network necessitates the need to perform handover between access segments to enable coverage extension and seamless connectivity. Handover procedures are analyzed, and an approach is presented that enables various operation and segment specific parameters to be taken into account when deciding upon the need to perform handover and in selecting the optimum access segment. In order to ensure transparency of network technology, the need for end-to-end QoS support is discussed, bearing in mind the deployment of both IntServ and DiffServ enabled routers in the core network. Following this, a new admission control scheme, named Gauge&Gate Reservation with Independent Probing (GRIP), is proposed. The paper concludes with a description of a laboratory testbed, which has been developed in order to verify the presented procedures, together with performance measurements of the handover and the GRIP algorithms.