394 research outputs found
Roaming Real-Time Applications - Mobility Services in IPv6 Networks
Emerging mobility standards within the next generation Internet Protocol,
IPv6, promise to continuously operate devices roaming between IP networks.
Associated with the paradigm of ubiquitous computing and communication, network
technology is on the spot to deliver voice and videoconferencing as a standard
internet solution. However, current roaming procedures are too slow, to remain
seamless for real-time applications. Multicast mobility still waits for a
convincing design. This paper investigates the temporal behaviour of mobile
IPv6 with dedicated focus on topological impacts. Extending the hierarchical
mobile IPv6 approach we suggest protocol improvements for a continuous
handover, which may serve bidirectional multicast communication, as well. Along
this line a multicast mobility concept is introduced as a service for clients
and sources, as they are of dedicated importance in multipoint conferencing
applications. The mechanisms introduced do not rely on assumptions of any
specific multicast routing protocol in use.Comment: 15 pages, 5 figure
New Mobility Trends in Data Networks
DizertaÄnĂ prĂĄce se zabĂœvĂĄ nĂĄvrhem novĂ©ho algoritmu ĆĂzenĂ handoveru v rĂĄmci protokolu Mobile IPv6, kterĂœ umoĆŸnĂ nasazenĂ tohoto protokolu v leteckĂœch datovĂœch sĂtĂch. ExistujĂcĂ algoritmy ĆĂzenĂ handoveru sice dosahujĂ dostateÄnĂ© vĂœkonnosti v konvenÄnĂch pozemnĂch bezdrĂĄtovĂœch sĂtĂch disponujĂch velkou ĆĄĂĆkou pĂĄsma a nĂzkou latencĂ, jako jsou WiFi nebo UMTS, ale jak ukazuje tato prĂĄce, nasazenĂ tÄchto algoritmĆŻ prostĆedĂ leteckĂœch datovĂœch sĂtĂ nepĆinĂĄĆĄĂ oÄekĂĄvanĂ© vĂœhody. AnalĂœza ukazuje, ĆŸe v ĂșzkopĂĄsmovĂœch leteckĂœch sĂtĂch trpĂ tyto algoritmy ĆĂzenĂ handoveru velkou latencĂ a zpĆŻsobujĂ znaÄnou reĆŸii. NovĂœ algoritmus ĆĂzenĂ handoveru v MIPv6 navrĆŸenĂœ v tĂ©to prĂĄci je zaloĆŸenĂœ na jednoduchĂ© myĆĄlence: ''JĂĄ jsem letadlo, jĂĄ vĂm, kam letĂm!'' To znamenĂĄ, ĆŸe pohyb letadla nenĂ nĂĄhodnĂœ, ale vysoce pĆedvĂdatelnĂœ. DĂky tomu je moĆŸno pĆedvĂdat handovery mezi pĆĂstupovĂœmi sĂtÄmi podĂ©l oÄekĂĄvanĂ© trajektorie letadla a vykonat nezbytnĂ© operace pro pĆĂpravu handoverĆŻ jiĆŸ na zemi, kde je letadlo pĆipojeno k ĆĄirokopĂĄsmovĂ© sĂti letiĆĄtÄ. Tato dizertaÄnĂ prĂĄce dĂĄle uvĂĄdĂ porovnĂĄnĂ existujĂcĂch algoritmĆŻ ĆĂzenĂ handoveru s novÄ navrĆŸenĂœm pomocĂ analytickĂ© metody ohodnocenĂ handoveru. DĂky tomu je moĆŸno kvantifikovat vĂœhody, kterĂ© novĂœ algoritmus pĆinĂĄĆĄĂ a taktĂ©ĆŸ popsat slabiny algoritmĆŻ existujĂcĂch.The doctoral thesis is focused on a design of novel Mobile IPv6 handover strategy suitable for deployment in aeronautical data networks. The current handover strategies provide sufficient performance in the conventional ground networks such as WiFi or UMTS that dispose high bandwidth and low latency. However, as this thesis shows, deploying these handover strategies in aeronautical data link environment does not bring desired benefits - the handover latency is high and the related overhead gets high as well. The novel MIPv6 handover strategy presented in this thesis is based on a simple thought: ''I am an aircraft, I know where I'm flying!'' This means that the movement of the aircraft is not random, it is highly predictable. Thanks to that, inter-network handovers may be anticipated and necessary IP handover related actions can be taken in advance, while the aircraft is connected via a broadband ground link at the origination airport. The thesis also presents a comparison of the existing handover strategies with the proposed new one conducted using an analytical approach. This allows to quantify the benefits of the novel handover strategy and the drawbacks of the current ones.
Scalable QoS-aware Mobility for Future Mobile Operators
Telecom operators and Internet service providers
are heading for a new shift in communications
paradigms. The forthcoming convergence
of cellular and wireless data networks is often
manifested in an âall IP approachâ in which all
communications are based on an end-to-end IP
protocol framework. The approach to network
design becomes user and service-centered, so
that continuous reachability of mobile users and
sustained communication capabilities are default
requirements for a prospective architecture. In
this article, we describe a network architecture
which is able to provide seamless communication
mobility, triggered either by the user or by the
network, across multiple technologies. The architecture
allows for media independent handovers
and supports optimized mobility and resource
management functions. The main focus of the
article is on major technical highlights of mobility
and quality-of-service (QoS) management subsystems
for converged networks.Publicad
Framework to facilitate smooth handovers between mobile IPv6 networks
Fourth generation (4G) mobile communication networks are characterised by heterogeneous access networks and IP based transport technologies. Different access technologies give users choices to select services such as levels of Quality of Service (QoS) support, business models and service providers. Flexibility of heterogeneous access is compounded by the overhead of scanning to discover accessible services, which added to the handoff latency. This thesis has developed mechanisms for service discovery and service selection, along with a novel proposal for mobility management architectures that reduced handoff latency.
The service discovery framework included a service advertisement data repository and a single frequency band access mechanism, which enabled users to explore services offered by various operators with a reduced scanning overhead. The novel hierarchical layout of the repository enabled it to categorise information into various layers and facilitate location based information retrieval. The information made available by the repository included cost, bandwidth, Packet Loss (PL), latency, jitter, Bit Error Rate (BER), location and service connectivity information. The single frequency band access mechanism further enabled users to explore service advertisements in the absence of their main service providers. The single frequency access mechanism broadcasted service advertisements information piggybacked onto a router advertisement packet on a reserved frequency band for advertisements. Results indicated that scanning 13 channels on 802.11 b interface takes 189ms whereas executing a query with maximum permissible search parameters on the service advertisement data repository takes 67ms.
A service selection algorithm was developed to make handoff decisions utilising the service advertisements acquired from the service discovery framework; based on a user's preference. The selection algorithm reduced the calculation overhead by eliminating unsuitable networks; based on interface compatibility, service provider location, unacceptable QoS (Quality of service) and unacceptable cost; from the selection process. The selection algorithm utilised cost, bandwidth, PL, latency, jitter, BER and terminal power for computing the most suitable network. Results indicated that the elimination based approach has improved the performance of the algorithm by 35% over non- elimination oriented selection procedures, even after utilising more selection parameters.
The service discovery framework and the service selection algorithm are flexible enough to be employed in most mobility management architectures. The thesis recommends Seamless Mobile Internet Protocol (SMIP) as a mobility management scheme based on the simulation results. The SMIP protocol, a combination of Hierarchical Mobile Internet Protocol (HMIP) and Fast Mobile Internet Protocol (FMIP), suffered hand off latency increases when undergoing a global handoff due to HMIP. The proposed modification to the HMIP included the introduction of a coverage area overlap, to reduce the global handoff latency. The introduction of a Home Address (HA) in Wireless Local Area Networks (WLAN) binding table enabled seamless handoffs from WLANs by having a redirection mechanism for the user's packets after handoff.
The thesis delivered a new mobility management architecture with mechanisms for service discovery and service selection. The proposed framework enabled user oriented, application centric and terminal based approach for selecting IPv6 networks
Mobile IP: state of the art report
Due to roaming, a mobile device may change its network attachment each time it moves to a new link. This might cause a disruption for the Internet data packets that have to reach the mobile node. Mobile IP is a protocol, developed by the Mobile IP Internet Engineering Task Force (IETF) working group, that is able to inform the network about this change in network attachment such that the Internet data packets will be delivered in a seamless way to the new point of attachment. This document presents current developments and research activities in the Mobile IP area
A network mobility management architecture for a heteregeneous network environment
Network mobility management enables mobility of personal area networks and vehicular networks across heterogeneous access networks using a Mobile Router. This dissertation presents a network mobility management architecture for minimizing the impact of handoffs on the communications of nodes in the mobile network. The architecture addresses mobility in legacy networks without infrastructure support, but can also exploit infrastructure support for improved handoff performance. Further, the proposed architecture increases the efficiency of communications of nodes in the mobile network with counter parts in the fixed network through the use of caching and route optimization. The performance and costs of the proposed architecture are evaluated through empirical and numerical analysis. The analysis shows the feasibility of the architecture in the networks of today and in those of the near future.Verkkojen liikkuuvudenhallinta mahdollistaa henkilökohtaisten ja ajoneuvoihin asennettujen verkkojen liikkuvuuden heterogeenisessÀ verkkoympÀristössÀ kÀyttÀen liikkuvaa reititintÀ. TÀmÀ vÀitöskirja esittÀÀ uuden arkkitehtuurin verkkojen liikkuvuudenhallintaan, joka minimoi verkonvaihdon vaikutuksen pÀÀtelaitteiden yhteyksiin.
Vanhoissa verkoissa, joiden infrastruktuuri ei tue verkkojen liikkuvuutta, verkonvaihdos tÀytyy hallita liikkuvassa reitittimessa. Standardoitu verkkojen liikkuvuudenhallintaprotokolla NEMO mahdollistaa tÀmÀn kÀyttÀen ankkurisolmua kiinteÀssÀ verkossa pakettien toimittamiseen pÀÀtelaitteiden kommunikaatiokumppaneilta liikkuvalle reitittimelle. NEMO:ssa verkonvaihdos aiheuttaa kÀynnissÀ olevien yhteyksien keskeytymisen yli sekunnin mittaiseksi ajaksi, aiheuttaen merkittÀvÀÀ hÀiriötÀ viestintÀsovelluksille.
EsitetyssÀ arkkitehtuurissa verkonvaihdon vaikutus minimoidaan varustamalla liikkuva reititin kahdella radiolla. KÀyttÀen kahta radiota liikkuva reititin pystyy suorittamaan verkonvaihdon keskeyttÀmÀttÀ pÀÀtelaitteiden yhteyksiÀ, mikÀli verkonvaihtoon on riittÀvÀsti aikaa. KÀytettÀvissa oleva aika riippuu liikkuvan reitittimen nopeudesta ja radioverkon rakenteesta. Arkkitehtuuri osaa myös hyödyntÀÀ infrastruktuurin tukea saumattomaan verkonvaihtoon. Verkkoinfrastruktuurin tuki nopeuttaa verkonvaihdosprosessia, kasvattaenmaksimaalista verkonvaihdos tahtia. TÀllöin liikkuva reitin voi kÀyttÀÀ lyhyen kantaman radioverkkoja, joiden solun sÀde on yli 80m, ajonopeuksilla 90m/s asti ilman, ettÀ verkonvaihdos keskeyttÀÀ pÀÀtelaitteiden yhteyksiÀ.
LisÀksi ehdotettu arkkitehtuuri tehostaa kommunikaatiota kÀyttÀen cache-palvelimia liikkuvassa ja kiinteÀssÀ verkossa ja optimoitua reititystÀ liikkuvien pÀÀtelaitteiden ja kiinteÀssÀ verkossa olevien kommunikaatiosolmujen vÀlillÀ. Cache-palvelinarkkitehtuuri hyödyntÀÀ vapaita radioresursseja liikkuvan verkon cache-palvelimen vÀlimuistin pÀivittÀmiseen. HeterogeenisessÀ verkkoympÀristossÀ cache-palvelimen pÀivitys suoritetaan lyhyen kantaman laajakaistaisia radioverkkoja kÀyttÀen. Liikkuvan reitittimen siirtyessÀ laajakaistaisen radioverkon peitealueen ulkopuolelle pÀÀtelaitteille palvellaan sisÀltöÀ, kuten www sivuja tai videota cache-palvelimelta, sÀÀstÀen laajemman kantaman radioverkon rajoitetumpia resursseja.
Arkkitehtuurissa kÀytetÀÀn optimoitua reititystÀ pÀÀtelaitteiden ja niiden kommunikaatiokumppaneiden vÀlillÀ. Optimoitu reititysmekanismi vÀhentÀÀ liikkuvuudenhallintaan kÀytettyjen protokollien langattoman verkon resurssien kulutusta. LisÀksi optimoitu reititysmekanismi tehostaa pakettien reititystÀ kÀyttÀen suorinta reittiÀ kommunikaatiosolmujen vÀlillÀ.
Esitetyn arkkitehtuurin suorituskyky arvioidaan empiirisen ja numeerisen analyysin avulla. Analyysi arvioi arkkitehtuurin suorituskykyÀ ja vertaa sitÀ aikaisemmin ehdotettuihin ratkaisuihin ja osoittaa arkkitehtuurin soveltuvan nykyisiin ja lÀhitulevaisuuden langattomiin verkkoihin.reviewe
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