A Survey of Multicast Routing Protocols for Ad-Hoc Wireless Networks

Abstract Many network applications require transmitting the same single copy of data packets concurrently to many destinations, it is called multicasting. Wired and infrastructure-based wireless networks are supported by many multicast routing protocols. But, applying this concept in Mobile Ad hoc wireless NETworks (MANETs) is a big challenge. Ad hoc wireless networks composed of self-organized mobile nodes that can move arbitrarily without any preexisting communication infrastructure base stations. It causes producing dynamic and unpredictable network topology. Many proposals are introduced trying to solve multicast supporting problem in MANETs. In this paper, multicast routing protocols in MANETs that was proposed in recent years will be classified according to different view points such as multicast topology, topology initialization, topology maintenance, core or coreless approach, and dependency on unicast routing protocols

Satellite Networks: Architectures, Applications, and Technologies

Since global satellite networks are moving to the forefront in enhancing the national and global information infrastructures due to communication satellites' unique networking characteristics, a workshop was organized to assess the progress made to date and chart the future. This workshop provided the forum to assess the current state-of-the-art, identify key issues, and highlight the emerging trends in the next-generation architectures, data protocol development, communication interoperability, and applications. Presentations on overview, state-of-the-art in research, development, deployment and applications and future trends on satellite networks are assembled

サービスレベルネゴシエーションに基づくワイヤレスネットワークのサービス提供スキーム

Tohoku University加藤寧課

Integrating LEO Satellite Constellations into Internet Backbone

Low Earth Orbit (LEO) satellite constellations have been used for ubiquitous and flexible Internet access services. However, a number of problems related to the integration of terrestrial with satellite hosts should be resolved for the effective exploitation of LEO constellations. LEO constellations are different from terrestrial Internet because of its special properties, which result in a lot of problems. A key issue is how to route Internet packets to the LEO constellation. In the thesis (1) the background of LEO constellations was introduced; (2) the obstacles of routing between the satellites and Internet were outlined; (3) The particular problem, which must be solved, is the routing burst stream traffic in LEO satellite constellations. Two novel routing algorithmsCControl Route Transmission (CRT) and CRT with bandwidth allocation (BCRT)Cwere utilized to address the bursts routing problem. CRT is an adaptive protocol which is able to minimize the congestion in the constellations. BCRT is a CRT extension which is allowed to class the traffic (e.g. video) with different QoS requirements and guarantees. Both of CRT and BCRT work in time epochs. Routes are computed on the basis of a directed weighted graph representing the global traffic traveling in the constellations. Both CRT and BCRT were evaluated via simulation and compared with other proposals in the literatures. The results showed that CRT is a simple algorithm, but the strategy produced by CRT could avoid the congestion and enhance the global resource usage in different traffic conditions. Moreover, the explicit reservation and reroute of BCRT greatly improve the performance of CRT. In particular, the dropping rate of BCRT is very low and the average delivery time is comparable with other proposals in the literatures.Low Earth Orbit (LEO) satellite constellations have been used for ubiquitous and flexible Internet access services. However, a number of problems related to the integration of terrestrial with satellite hosts should be resolved for the effective exploitation of LEO constellations. LEO constellations are different from terrestrial Internet because of its special properties, which result in a lot of problems. A key issue is how to route Internet packets to the LEO constellation. In the thesis (1) the background of LEO constellations was introduced; (2) the obstacles of routing between the satellites and Internet were outlined; (3) The particular problem, which must be solved, is the routing burst stream traffic in LEO satellite constellations. Two novel routing algorithmsCControl Route Transmission (CRT) and CRT with bandwidth allocation (BCRT)Cwere utilized to address the bursts routing problem. CRT is an adaptive protocol which is able to minimize the congestion in the constellations. BCRT is a CRT extension which is allowed to class the traffic (e.g. video) with different QoS requirements and guarantees. Both of CRT and BCRT work in time epochs. Routes are computed on the basis of a directed weighted graph representing the global traffic traveling in the constellations. Both CRT and BCRT were evaluated via simulation and compared with other proposals in the literatures. The results showed that CRT is a simple algorithm, but the strategy produced by CRT could avoid the congestion and enhance the global resource usage in different traffic conditions. Moreover, the explicit reservation and reroute of BCRT greatly improve the performance of CRT. In particular, the dropping rate of BCRT is very low and the average delivery time is comparable with other proposals in the literatures

IP and ATM integration: A New paradigm in multi-service internetworking

ATM is a widespread technology adopted by many to support advanced data communication, in particular efficient Internet services provision. The expected challenges of multimedia communication together with the increasing massive utilization of IP-based applications urgently require redesign of networking solutions in terms of both new functionalities and enhanced performance. However, the networking context is affected by so many changes, and to some extent chaotic growth, that any approach based on a structured and complex top-down architecture is unlikely to be applicable. Instead, an approach based on finding out the best match between realistic service requirements and the pragmatic, intelligent use of technical opportunities made available by the product market seems more appropriate. By following this approach, innovations and improvements can be introduced at different times, not necessarily complying with each other according to a coherent overall design. With the aim of pursuing feasible innovations in the different networking aspects, we look at both IP and ATM internetworking in order to investigating a few of the most crucial topics/ issues related to the IP and ATM integration perspective. This research would also address various means of internetworking the Internet Protocol (IP) and Asynchronous Transfer Mode (ATM) with an objective of identifying the best possible means of delivering Quality of Service (QoS) requirements for multi-service applications, exploiting the meritorious features that IP and ATM have to offer. Although IP and ATM often have been viewed as competitors, their complementary strengths and limitations from a natural alliance that combines the best aspects of both the technologies. For instance, one limitation of ATM networks has been the relatively large gap between the speed of the network paths and the control operations needed to configure those data paths to meet changing user needs. IP\u27s greatest strength, on the other hand, is the inherent flexibility and its capacity to adapt rapidly to changing conditions. These complementary strengths and limitations make it natural to combine IP with ATM to obtain the best that each has to offer. Over time many models and architectures have evolved for IP/ATM internetworking and they have impacted the fundamental thinking in internetworking IP and ATM. These technologies, architectures, models and implementations will be reviewed in greater detail in addressing possible issues in integrating these architectures s in a multi-service, enterprise network. The objective being to make recommendations as to the best means of interworking the two in exploiting the salient features of one another to provide a faster, reliable, scalable, robust, QoS aware network in the most economical manner. How IP will be carried over ATM when a commercial worldwide ATM network is deployed is not addressed and the details of such a network still remain in a state of flux to specify anything concrete. Our research findings culminated with a strong recommendation that the best model to adopt, in light of the impending integrated service requirements of future multi-service environments, is an ATM core with IP at the edges to realize the best of both technologies in delivering QoS guarantees in a seamless manner to any node in the enterprise

Flow control of real-time unicast multimedia applications in best-effort networks

One of the fastest growing segments of Internet applications are real-time mul- timedia applications, like Voice over Internet Protocol (VoIP). Real-time multimedia applications use the User Datagram Protocol (UDP) as the transport protocol because of the inherent conservative nature of the congestion avoidance schemes of Transmis- sion Control Protocol (TCP). The e®ects of uncontrolled °ows on the Internet have not yet been felt because UDP tra±c frequently constitutes only » 20% of the total Internet tra±c. It is pertinent that real-time multimedia applications become better citizens of the Internet, while at the same time deliver acceptable Quality of Service (QoS). Traditionally, packet losses and the increase in the end-to-end delay experienced by some of the packets characterizes congestion in the network. These two signals have been used to develop most known °ow control schemes. The current research considers the °ow accumulation in the network as the signal for use in °ow control. The most signi¯cant contribution of the current research is to propose novel end- to-end °ow control schemes for unicast real-time multimedia °ows transmitting over best-e®ort networks. These control schemes are based on predictive control of the accumulation signal. The end-to-end control schemes available in the literature are based on reactive control that do not take into account the feedback delay existing between the sender and the receiver nor the forward delay in the °ow dynamics. The performance of the proposed control schemes has been evaluated using the ns-2 simulation environment. The research concludes that active control of hard real- time °ows delivers the same or somewhat better QoS as High Bit Rate (HBR, no control), but with a lower average bit rate. Consequently, it helps reduce bandwidth use of controlled real-time °ows by anywhere between 31:43% to 43:96%. Proposed reactive control schemes deliver good QoS. However, they do not scale up as well as the predictive control schemes. Proposed predictive control schemes are e®ective in delivering good quality QoS while using up less bandwidth than even the reactive con- trol schemes. They scale up well as more real-time multimedia °ows start employing them

Security-centric analysis and performance investigation of IEEE 802.16 WiMAX

fi=vertaisarvioitu|en=peerReviewed

Efficient Passive Clustering and Gateways selection MANETs

Passive clustering does not employ control packets to collect topological information in ad hoc networks. In our proposal, we avoid making frequent changes in cluster architecture due to repeated election and re-election of cluster heads and gateways. Our primary objective has been to make Passive Clustering more practical by employing optimal number of gateways and reduce the number of rebroadcast packets