4 research outputs found
Applying named data networking in mobile ad hoc networks
This thesis presents the Name-based Mobile Ad-hoc Network (nMANET) approach
to content distribution that ensure and enables responsible research on applying
named data networking protocol in mobile ad-hoc networks. The test framework
of the nMANET approach allows reproducibility of experiments and validation of
expected results based on analysis of experimental data. The area of application for
nMANETs is the distribution of humanitarian information in emergency scenarios.
Named-Data Networking (NDN) and ad-hoc mobile communication allow exchange
of emergency information in situations where central services such as cellular towers
and electric systems are disrupted.
The implemented prototype enables researchers to reproduce experiments on
content distribution that consider constraints on mobile resources, such as the
remaining power of mobile devices and available network bandwidth. The nMANET
framework validates a set of experiments by measuring network traffic and energy
consumption from both real mobile devices and those in a simulated environment.
Additionally, this thesis presents results from experiments in which the nMANET
forwarding strategies and traditional wireless services, such as hotpost, are analysed
and compared. This experimental data represents the evidence that supports and
validates the methodology presented in this thesis.
The design and implementation of an nMANET prototype, the Java NDN Forwarder
Daemon (JNFD) is presented as a testing framework, which follows the principles
of continuous integration, continuous testing and continuous deployment. This
testing framework is used to validate JNFD and IP-based technologies, such as
HTTP in a MANET using the OLSR routing protocol, as well as traditional wireless
infrastructure mode wireless.
The set of experiments executed, in a small network of Android smart-phones
connected in ad-hoc mode and in a virtual ad-hoc network simulator show the
advantages of reproducibility using nMANET features. JNFD is open source, all
experiments are scripted, they are repeatable and scalable. Additionally, JNFD
utilises real GPS traces to simulate mobility of nodes during experiments. This
thesis provides experimental evidence to show that nMANET allows reproducibility
and validation of a wide range of future experiments applying NDN on MANETs
A link-state based on-demand routing protocol supporting real-time traffic for wireless mobile ad hoc networks
Ankara : The Department of Computer Engineering and the Institute of Engineering and Science of Bilkent University, 2007.Thesis (Master's) -- Bilkent University, 2007.Includes bibliographical references leaves 200-212.Wireless ad hoc networks have gained a lot of popularity since their introduction
and as many wireless network interface cards provide support for ad hoc
networking, such networks have also seen real-life deployment for non-specialized
purposes. Wireless mobile ad hoc networks (MANETs) are currently the most
common type of ad hoc networks, and such networks are especially esteemed for
their mobility support and ease of deployment due to their ad hoc nature. As
most common network applications, such as the Web, FTP, email, and instant
messaging, are data-centric and do not operate under strict time constraints,
MANETs have been deployed to enable such non-real-time applications in the
past. However, with the increasing use of real-time applications over ad hoc
networks, such as teleconferencing, VoIP, and security and tracking applications
where timeliness is of importance, real-time traffic support in multi-hop wireless
mobile ad hoc networks has become an issue.
We propose an event-driven, link-state based, on-demand routing protocol to
enable real-time traffic support in such multi-hop wireless mobile ad hoc networks.
Our protocol, which is named Elessar, is based on link-state topology
dissemination, but instead of the more common periodic link-state messaging
scheme, we employ event-driven link-state messages in Elessar, where topology
changes are the events of interest. Through such an approach, we aim to lower the
overhead of our protocol, especially for low-mobility cases, which is currently the
most commonly encountered case with ad hoc networks deployed with machines
directly interacting with humans, such as PDAs and laptops. Due to its link-state
nature, our protocol is able to support non-real-time traffic without any further
action. In order to support real-time traffic, however, we employ a direct cost
dissemination mechanism, which only operates on-demand when there are one or
more real-time flows in the network. We aim to provide soft quality-of-service
(QoS) guarantees to real-time flows through intelligent path selection, without
any resource reservation. We also aim to provide such QoS guarantees throughout
the lifetime of a real-time flow, even in the face of node failures and mobility,
by dynamic path adaptation during the lifetime of the flow. Elessar is able to
support real-time and non-real-time traffic concurrently, as well as various different
types of concurrent real-time traffic, such as delay- and loss-sensitive traffic.
Our protocol, therefore, does not aim to support a single type of real-time traffic,
but rather a plethora of different types of real-time traffic. Elessar is completely
distributed, dynamic and adaptive, and does not require the underlying MAC
protocol to be QoS-aware.
We analyse our design choices and the performance of our protocol through
realistic simulation experiments conducted on the OMNeT++ discrete event simulation
platform, using the INET framework. We have used the IEEE 802.11b
MAC protocol during our simulations and have employed the random waypoint
mobility model to simulate mobility. Our experimental results show that Elessar
is able to efficiently provide real-time traffic support for different types of traf-
fic flows, even in the face of mobility. Our protocol operates best for smallto-medium-sized
networks where mobility rates are low-to-medium. Once the
mobility rate exceeds a certain threshold, intelligent path selection cannot cope
satisfactorily with the high dynamism of the environment and the overhead of
Elessar exceeds acceptable levels due to its event-driven link-state nature.Görbil, GökçeM.S
Data Storage and Dissemination in Pervasive Edge Computing Environments
Nowadays, smart mobile devices generate huge amounts of data in all sorts of gatherings.
Much of that data has localized and ephemeral interest, but can be of great use if shared
among co-located devices. However, mobile devices often experience poor connectivity,
leading to availability issues if application storage and logic are fully delegated to a
remote cloud infrastructure. In turn, the edge computing paradigm pushes computations
and storage beyond the data center, closer to end-user devices where data is generated
and consumed. Hence, enabling the execution of certain components of edge-enabled
systems directly and cooperatively on edge devices.
This thesis focuses on the design and evaluation of resilient and efficient data storage
and dissemination solutions for pervasive edge computing environments, operating with
or without access to the network infrastructure. In line with this dichotomy, our goal can
be divided into two specific scenarios. The first one is related to the absence of network
infrastructure and the provision of a transient data storage and dissemination system
for networks of co-located mobile devices. The second one relates with the existence of
network infrastructure access and the corresponding edge computing capabilities.
First, the thesis presents time-aware reactive storage (TARS), a reactive data storage
and dissemination model with intrinsic time-awareness, that exploits synergies between
the storage substrate and the publish/subscribe paradigm, and allows queries within a
specific time scope. Next, it describes in more detail: i) Thyme, a data storage and dis-
semination system for wireless edge environments, implementing TARS; ii) Parsley, a
flexible and resilient group-based distributed hash table with preemptive peer relocation
and a dynamic data sharding mechanism; and iii) Thyme GardenBed, a framework
for data storage and dissemination across multi-region edge networks, that makes use of
both device-to-device and edge interactions.
The developed solutions present low overheads, while providing adequate response
times for interactive usage and low energy consumption, proving to be practical in a
variety of situations. They also display good load balancing and fault tolerance properties.Resumo
Hoje em dia, os dispositivos móveis inteligentes geram grandes quantidades de dados
em todos os tipos de aglomerações de pessoas. Muitos desses dados têm interesse loca-
lizado e efêmero, mas podem ser de grande utilidade se partilhados entre dispositivos
co-localizados. No entanto, os dispositivos móveis muitas vezes experienciam fraca co-
nectividade, levando a problemas de disponibilidade se o armazenamento e a lógica das
aplicações forem totalmente delegados numa infraestrutura remota na nuvem. Por sua
vez, o paradigma de computação na periferia da rede leva as computações e o armazena-
mento para além dos centros de dados, para mais perto dos dispositivos dos utilizadores
finais onde os dados são gerados e consumidos. Assim, permitindo a execução de certos
componentes de sistemas direta e cooperativamente em dispositivos na periferia da rede.
Esta tese foca-se no desenho e avaliação de soluções resilientes e eficientes para arma-
zenamento e disseminação de dados em ambientes pervasivos de computação na periferia
da rede, operando com ou sem acesso à infraestrutura de rede. Em linha com esta dico-
tomia, o nosso objetivo pode ser dividido em dois cenários específicos. O primeiro está
relacionado com a ausência de infraestrutura de rede e o fornecimento de um sistema
efêmero de armazenamento e disseminação de dados para redes de dispositivos móveis
co-localizados. O segundo diz respeito à existência de acesso à infraestrutura de rede e
aos recursos de computação na periferia da rede correspondentes.
Primeiramente, a tese apresenta armazenamento reativo ciente do tempo (ARCT), um
modelo reativo de armazenamento e disseminação de dados com percepção intrínseca
do tempo, que explora sinergias entre o substrato de armazenamento e o paradigma pu-
blicação/subscrição, e permite consultas num escopo de tempo específico. De seguida,
descreve em mais detalhe: i) Thyme, um sistema de armazenamento e disseminação de
dados para ambientes sem fios na periferia da rede, que implementa ARCT; ii) Pars-
ley, uma tabela de dispersão distribuída flexível e resiliente baseada em grupos, com
realocação preventiva de nós e um mecanismo de particionamento dinâmico de dados; e
iii) Thyme GardenBed, um sistema para armazenamento e disseminação de dados em
redes multi-regionais na periferia da rede, que faz uso de interações entre dispositivos e
com a periferia da rede.
As soluções desenvolvidas apresentam baixos custos, proporcionando tempos de res-
posta adequados para uso interativo e baixo consumo de energia, demonstrando serem
práticas nas mais diversas situações. Estas soluções também exibem boas propriedades de balanceamento de carga e tolerância a faltas