7 research outputs found
QoS in Node-disjoint Routing for Ad Hoc Networks
PhDA mobile ad hoc network (MANET) is a collection of mobile nodes that
can communicate with each other without using any fixed infrastructure.
It is necessary for MANETs to have efficient routing protocol and quality
of service (QoS) mechanism to support multimedia applications such as
video and voice.
Node-Disjoint Multipath Routing Protocol (NDMR) is a practical protocol
in MANETs: it reduces routing overhead dramatically and achieves
multiple node-disjoint routing paths.
Because QoS support in MANETs is important as best-effort routing is
not efficient for supporting multimedia applications, this thesis presents a
novel approach to provide that support.
In this thesis NDMR is enhanced to provide a QoS enabled NDMR that
decreases the transmission delay between source and destination nodes.
A multi-rate mechanism is also implemented in the new protocol so that
the NDMR QoS can minimise the overall delays. It is shown that these
approaches lead to significant performance gains. A modification to
NDMR is also proposed to overcome some of the limitations of the
original
Multipath routing and QoS provisioning in mobile ad hoc networks
PhDA Mobile Ad Hoc Networks (MANET) is a collection of mobile nodes that can
communicate with each other using multihop wireless links without utilizing any
fixed based-station infrastructure and centralized management. Each mobile node
in the network acts as both a host generating flows or being destination of flows
and a router forwarding flows directed to other nodes.
Future applications of MANETs are expected to be based on all-IP
architecture and be capable of carrying multitude real-time multimedia
applications such as voice and video as well as data. It is very necessary for
MANETs to have an efficient routing and quality of service (QoS) mechanism to
support diverse applications.
This thesis proposes an on-demand Node-Disjoint Multipath Routing protocol
(NDMR) with low broadcast redundancy. Multipath routing allows the
establishment of multiple paths between a single source and single destination
node. It is also beneficial to avoid traffic congestion and frequent link breaks in
communication because of the mobility of nodes. The important components of
the protocol, such as path accumulation, decreasing routing overhead and
selecting node-disjoint paths, are explained. Because the new protocol
significantly reduces the total number of Route Request packets, this results in an
increased delivery ratio, smaller end-to-end delays for data packets, lower control
overhead and fewer collisions of packets.
Although NDMR provides node-disjoint multipath routing with low route
overhead in MANETs, it is only a best-effort routing approach, which is not
enough to support QoS. DiffServ is a standard approach for a more scalable way
to achieve QoS in any IP network and could potentially be used to provide QoS
in MANETs because it minimises the need for signalling. However, one of the
biggest drawbacks of DiffServ is that the QoS provisioning is separate from the
routing process. This thesis presents a Multipath QoS Routing protocol for
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supporting DiffServ (MQRD), which combines the advantages of NDMR and
DiffServ. The protocol can classify network traffic into different priority levels
and apply priority scheduling and queuing management mechanisms to obtain
QoS guarantees
Exploiting the power of multiplicity: a holistic survey of network-layer multipath
The Internet is inherently a multipath network: For an underlying network with only a single path, connecting various nodes would have been debilitatingly fragile. Unfortunately, traditional Internet technologies have been designed around the restrictive assumption of a single working path between a source and a destination. The lack of native multipath support constrains network performance even as the underlying network is richly connected and has redundant multiple paths. Computer networks can exploit the power of multiplicity, through which a diverse collection of paths is resource pooled as a single resource, to unlock the inherent redundancy of the Internet. This opens up a new vista of opportunities, promising increased throughput (through concurrent usage of multiple paths) and increased reliability and fault tolerance (through the use of multiple paths in backup/redundant arrangements). There are many emerging trends in networking that signify that the Internet's future will be multipath, including the use of multipath technology in data center computing; the ready availability of multiple heterogeneous radio interfaces in wireless (such as Wi-Fi and cellular) in wireless devices; ubiquity of mobile devices that are multihomed with heterogeneous access networks; and the development and standardization of multipath transport protocols such as multipath TCP. The aim of this paper is to provide a comprehensive survey of the literature on network-layer multipath solutions. We will present a detailed investigation of two important design issues, namely, the control plane problem of how to compute and select the routes and the data plane problem of how to split the flow on the computed paths. The main contribution of this paper is a systematic articulation of the main design issues in network-layer multipath routing along with a broad-ranging survey of the vast literature on network-layer multipathing. We also highlight open issues and identify directions for future work
InfiniBand-Based Mechanism to Enhance Multipath QoS in MANETs
Mobile Ad-hoc Networks (MANETs), the continuous changes in topology and the big amounts of data exchanged across the network makes it difficult for a single routing algorithm to route data efficiently between nodes. MANETs usually suffer from high packet loss rates and high link failure rates, which also makes it difficult to exchange data in
effective and reliable fashion. These challenges usually increase congestion on some links while other links are almost free. In this thesis, we propose a novel mechanism to enhance QoS in multipath routing protocols in MANETs based on the InfiniBand (IB) QoS architecture. The basic idea of our approach is to enhance the path balancing to reduce congestion on overloaded links. This mechanism has enabled us to give critical applications higher priority to send them packet when
routing their packets across the network, effectively manage frequent connections and disconnections and thus help reduce link failures and packet loss rates, and reduce the overall power consumption as a consequence of the previous gains. We have tested the scheme on the (IBMGTSim) simulator and achieved significant improvements in QoS parameters compared to two well-known routing protocols: AODV and AOMDV.هناك نوع من الشبكات حيث يكون كل المكونات فيها عبارة عن اجهزة متحركة بدون اي بنية تحتية
تسمى "MANET "في هذا النوع من الشبكات تتعاون االجهزة ذاتيا لتحديد الطرق في ما بينها
والنها متحركة تقوم هذه االجهزة بحساب اكثر من طريق عو ًضا عن حساب طريق واحد لتقليل من
احتمالية فشل في االرسال حيث اذا تم فشل في طريق معينة تبقى الطرق االخرة سليمة.
وفي ناحية اخرى ولتنوع اهمية البرامج والخدمات التي توفرها هذه االجهزة هناك ما يسمى
"بجودى الخدمات Service of Quality" حيث يقوم المستخدم بوضع اولويات للبرامج
والخدمات من استهالك المصادر المتاحة, والطريق الشائعة هي ان يقوم المستخدم بوضع حدود على
سرعة استعمال الشبكة من قبل البرامج االقل اهمية لترك المصادر متاحة للبرامج الاكثر المهمة
بشكل اكثر وهذا الحل يحتوي على الكثير من المشاكل في هذا النوع من الشبكات, حيث ان
مواصفات الطرق غير معروفة وغير ثابتة وقد تحتوي او تتغير الى قيم اقل من الحدود الموضوعة
للبرمج الغير مهمة فتتساوى البرامج والخدمات االقل اهمية بالبرامج االكثر اهمية مما يعني فشل في
جودة الخدمات.
من خالل بحثنا عن حلول ودراسة انواع مختلفة من الشبكات وجدنا نوع من تطبيق جودة الخدمات
في نوع الشبكات المسمى بInfiniBand حيث يتم تطبيق جودة الخدمات من خالل تغيير عدد
الرسال المبعثة من قبل البرامج, حيث تقوم االجهزة بارسال عدد اكبر من الرسال التابعة للبرامج
المهمة مقارنة بعدد الرسال التابعة للبرامج االقل اهمية, ويتم ذلك باستخدام الصفوف, حيث تصطف
الرسال من البرامج المهمة بصف يختلف عن الصف الذي يحتوي على رسال البرامج الغير مهمة.
هذا الحل له فائدتان مهمتان االولى انه ال يوثر عالطريقة التقليدية ويمكن ان يستخدم معها والفائدة
الثانية انه وبخالف الطريقة التقليدية, الطريقة الجديدة ال تتاثر بصفات الطريق المحسوبة او بتغير
صفاتها فنسبة عدد الرسال تكون نفسها مهما اختلفت الطرق و صفاتها, بعد تطبيق هذا النوع
وجددنا تحسين في كفائة االرسال تصل الى 18 %في جودة التوصيل و 10 %في سرعة الوصول
مع العلم ان جودة الخدمات لم تفشل على غرار الطريقة التقليدية
A Hierarchical Structure towards Securing Data Transmission in Cognitive Radio Networks
Cognitive Radio (CR) technology is considered as a promising technology to overcome
spectrum scarcity problem in wireless networks, by sharing the spectrum between both unlicensed
users (secondary users, (SUs)) and licensed users (primary users, (PUs)), provided that the SUs
respect the PUs’ rights to use the spectrum exclusively.
An important technical area in cognitive radio networks (CRNs) is wireless security. A
secure CRN must meet different security requirements, which are: confidentiality, integrity,
availability and authentication. Data confidentiality is a mandatory requirement in cognitive radio
networks, generally to maintain the privacy of the data owner (PU or SU). Integrity means that
data is transmitted from the source to the destination without alteration. While availability is to
release the channels assigned to one SU as soon as a PU wants to use its spectrum. Authentication
in CRN means that each node has to authenticate itself before it can use the available spectrum
channels.
New classes of security threats and challenges in CRNs have been introduced that target
the different layers of OSI model and affect the security requirements. Providing strong security
may prove to be the most difficult aspect of making CR a long-term commercially-viable concept.
Protection of routes used for data transmission is a critical prerequisite to ensure the robustness of
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the routing process. Therefore, route discovery must be done in such a way that lets each node find
the best secure path(s) for its data transmission.
In this work, network security of CRN is improved through proposing different models that
are built to fulfil the security requirements mentioned above. Improving the network security
enhances the network performance, taking into consideration the quality of service (QoS) desired
by the different network nodes such as bandwidth and time delay. This work aims to combine the
spectrum sensing phase and the spectrum management phase, as well as to detect all the adversary
nodes that slow down the network performance by selectively holding and not forwarding packets
to their next hop(s). We measure the network node’s reliability for using network resources
through a value called belief level (BL), which is considered as the main parameter for our entire
work. BL is used to monitor the nodes’ behavior during the spectrum sensing phase, and then it is
used to form the best path(s) during the spectrum management phase. Particularly, this work
follows a hierarchical structure that has three different layers. At the bottom layer, a novel
authentication mechanism is developed to fulfil the authentication and the availability security
requirements, which ends assigning a belief level (BL) to each node. At the middle layer, the
nodes’ behavior during the spectrum sensing phase is monitored to detect all the adversary node(s).
Finally, at the top layer, a novel routing algorithm is proposed that uses the nodes’ security (BL)
as a routing metric. SUs collaborate with each other to monitor other nodes’ behavior. Users’ data
confidentiality and integrity are satisfied through this hierarchical structure that uses the cluster-based,
central authority, and nodes collaboration concepts. By doing so, the traffic carried in the
CRN is secured and adversary nodes are detected and penalized