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8th International Workshop on the Design of Reliable Communication Networks, DRCN 2011, Krakow, Poland, 10-12 October, 2011; 01/2011
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Optical Switching and Networking. 01/2010; 7:115-126.
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IEEE Systems Journal. 01/2010; 4:561-572.
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IEEE 6th International Conference on Wireless and Mobile Computing, Networking and Communications, WiMob 2010, Niagara Falls, Ontario, Canada, 11-13 October, 2010; 01/2010
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Access Networks, 4th International Conference, AccessNets 2009, Hong Kong, China, November 1-3, 2009, Revised Selected Papers; 01/2009
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IEEE Communications Surveys and Tutorials. 01/2008; 10:70-86.
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Proceedings of the Global Communications Conference, 2007. GLOBECOM '07, Washington, DC, USA, 26-30 November 2007; 01/2007
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ABSTRACT: Multi-copy utility based routing strategies have been con-sidered the most applicable approaches to achieve message delivery in Delay Tolerant Networks (DTNs). They allow multiple message replicas to be launched to increase the ratio of message delivery or reduce its delay. This advan-tage, nonetheless, is at the expense of taking more buffer space at each node. The combination of custody and repli-cation entails high buffer and bandwidth overhead. There-fore, efficient scheduling policies are needed to decide which messages to forward first when the available bandwidth is limited, and which messages to drop first when the buffer operates close to its capacity. This paper investigates an efficient message scheduling and dropping policies based on the theory of the encounter-based message forwarding, and the expected number of copies of the message that have been disseminated in the network, such that the forwarding and dropping decisions result in optimal message delivery de-lays. Extensive simulations results, based on a synthetic mobility model and real mobility traces, show that the pro-posed scheduling framework can achieve superb performance against its counterparts in terms of delivery delay.
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ABSTRACT: This paper introduces a novel multi-copy routing protocol, called Self Adaptive Utility-based Routing Protocol (SAURP), for Delay Tolerant Networks (DTNs) that are pos-sibly composed of a vast number of miniature devices such as smart phones, hand-held devices, and sensors mounted in fixed or mobile objects. SAURP aims to explore the possibility of taking mobile nodes as message carriers in order for end-to-end delivery of the messages. The best carrier for a message is determined by the prediction result using a novel contact model, where the network status, including wireless link condition and nodal buffer availability, are jointly considered. The paper argues and proves that the nodal movement and the predicted collocation with the message recipient can serve as meaningful information to achieve an intelligent message forwarding decision at each node. The proposed protocol has been implemented and compared with a number of existing encounter-based routing approaches in terms of delivery delay, and the number of transmissions required for message delivery. The simulation results show that the proposed SAURP outper-forms all the counterpart multi-copy encounter-based routing protocols considered in the study.
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ABSTRACT: Delay tolerant networks (DTNs) are wireless networks in which an end-to-end path for a given node pair can never exist for an extended period. It has been reported as a viable approach in launching multiple message replicas in order to increase message delivery ratio and reduce message delivery delay. This advantage, nonetheless, is at the ex-pense of taking more buer space at each node. The combination of cus-tody and replication entails high buer and bandwidth overhead. This paper investigates a new buer management architecture for epidemic routing in DTNs, which helps each node to make a decision on which message should be forwarded or dropped. The proposed buer manage-ment architecture is characterized by a suite of novel functional modules, including Summary Vector Exchange Module (SVEM), Networks State Estimation Module (NSEM), and Utility Calculation Module (UCM). Extensive simulation results show that the proposed buer management architecture can achieve superb performance against its counterparts in terms of delivery ratio and delivery delay.
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ABSTRACT: The future optical Internet based on the Optical Burst Switching (OBS) technology is expected to provision ultra-dynamic bandwidth for multi-custom applications. Data bursts with variable lengths are delivered in the underlying optical layer based on an asynchronous operation mode. Under the framework of OBS routing and signaling, a novel protocol called Domain-based Resource Reservation Protocol (DRRP) is proposed. The proposed scheme partitions the OBS core network into multiple domains, each maintaining its local resource availability and routing information. A compromise is initiated between the throughput and the delay due to nodal processing by jointly considering Fixed Path Routing (FPR) and Hop-by-Hop Routing (HHR) in the inter-and intra domain path selection. Extensive simulations show that the proposed approach have improved the overall network throughput and reduced the average blocking probability thus reduces the retransmission delay.
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ABSTRACT: Due to the bufferless nature of Optical Burst Switched network, contentions occur even at low traffic loads, leading to burst losses. Contention resolution schemes, such as burst retransmission and deflection, can reduce burst losses, especially at low traffic loads. However, both schemes result in additional packet delay for the packets in bursts that are retransmitted or deflected. The additional packet delay affects the performance of delay-based TCP implementations that rely on packet delay to estimate available bandwidth in networks and to detect network congestion state. In this paper, we discuss the issues of TCP Vegas over OBS networks and propose a threshold-based TCP Vegas version that is suitable for the characteristics of OBS networks. The threshold-based TCP Vegas are able to distinguish whether the increases in packet delay are due to network congestion, or due to burst contentions at low traffic loads. Our simulation results show that the threshold-based TCP Vegas has higher throughput for a TCP connection compared to TCP Vegas and the loss-based TCP implementations, such as TCP Sack.
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ABSTRACT: We propose TMAC, a timestamp-ordered MAC protocol for Wireless Mesh Networks (WMNs). TMAC extends CSMA/CA by scheduling data packets based on their age. Prior to transmitting a data packet, a transmitter broadcasts a request control message appended with a timestamp to a selected list of neighbors. It can proceed with the transmission only if it receives a sufficient number of grant control messages from these neighbors. A grant message indicates that the associated data packet has the lowest timestamp of all the packets pending transmission at the local transmit queue. We demonstrate that a loose ordering of timestamps among neighboring nodes is sufficient for enforcing local fairness, subsequently leading to flow rate fairness in a multi-hop WMN. We show that TMAC can be implemented using the control frames in IEEE 802.11 stack, and thus can be easily integrated in existing 802.11-based WMNs. Our simulation results show that TMAC achieves excellent resource allocation fairness while maintaining over 90% of maximum link capacity in parking lot and large grid topologies.
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ABSTRACT: In this paper, a novel congestion control scheme with dynamic Burst-Contention Loss notifications in Optical Burst Switching (OBS) networks is proposed. The proposed scheme, called TCP-BCL, aims to handle various OBS bursty conditions that negatively affect TCP throughput performance and fairness. The basic design principle of the scheme is to tune the congestion control parameters α and β such that the congestion window sizes in the corresponding TCP senders can be adjusted with an explicit notification from the OBS edge node. The performance impact on TCP in terms of burst dropping due to random contention, which is also known as false congestion detection is considered and investigated. An analytical model is developed and further verified through extensive simulation.
Computer Networks.
