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With its new features such as multi-homing and multi-streaming the Stream Control Transmission Protocol (SCTP) has become a promising candidate as a general-purpose transport layer protocol. Multi-homing in an SCTP association can make concurrent multi-path transfer an appealing candidate to satisfy the ever increasing user demands for bandwidth. Multiple streams provide an aggregation mechanism to...
New advanced transmission protocols are required to fulfill the cost-efficiency objective of next generation mobile communications systems. This paper presents the study and performance evaluation of a two-relay assisted cooperative transmission protocol which could make a good candidate technique to improve the capacity and the quality of service of future cellular networks. Simulation results obtained...
This paper presents transport methods that overcome loss and contention in radio networks while servicing multiple applications in a System of Systems environment. UDP with application-level retry avoids TCP's tendency to misinterpret loss as contention. Prioritized FIFO queues combine various data streams (Unicast and Multicast, reliably delivered and send once, low and high priority, small messages...
The RED scheme allows to prevent global synchronization of the sources associated with drop-tail buffers. But the drop-tail discipline could lead to strong oscillations and complex behavior of the system. In this paper, a model of TCP network using RED is described, including RED drop function and model of TCP source. Secondly, the linear analysis of a single link topology is focused. Finally, a sufficient...
Computational grids have emerged as a new paradigm for solving large complex problems over the recent years. The problem space and data set are divided into smaller pieces that are processed in parallel over the grid network and reassembled upon completion. Typically, resources are logged into a resource broker that is somewhat aware of all of the participants available on the grid. The resource broker...
In this paper, we propose a new variant of TCP with an early retransmission scheme as an enhancement to make it more suitable for streaming media. We call this new protocol TCP-ER. We performed extensive ns2 simulations to show that: 1) The early retransmission scheme can considerably reduce the number of retransmission timeouts and packet delay jitter in a variety of network environments. 2) TCP-ER...
The steadily growing importance of Internet-based applications and their resilience requirements lead to a rising number of multi-homed sites. The idea of Concurrent Multipath Transfer (CMT) is to exploit the existence of multiple paths among endpoints to increase application data throughput. However, handling the congestion control of each path independently lacks of fairness against non-CMT flows...
Without proper receiving buffer assignment, Concurrent Multipath Transfer (CMT) could result in either not being able to achieve aggregate bandwidth or being a waste of memory resources. This paper analyses buffer requirement for CMT and find that receive buffer requirement is linearly correlated to ratio of round trip time of different path. Based on buffer requirement analysis, this paper proposes...
In wired-cum-wireless networks, one of the main design challenges for TCP is to accurately distinguish congestion losses from random losses caused due to channel noise and interference. TCP Veno has been widely deployed in wireless networks to address this challenge. TCP Veno has been demonstrated to show better performance than TCP Reno in wired-cum-wireless environments. However, TCP Veno does not...
While Transmission Control Protocol (TCP) is the most popular transport protocol used in terrestrial networks, its performance is not adequate in wireless networks with long delay, e.g., satellite networks. Though some improvements of TCP and new transport protocols have been proposed, we focus on Variable-structure congestion Control Protocol (VCP) designed for high Bandwidth Delay Product (BDP)...
Various studies have shown that regular TCP is inefficient in high-speed networks. This paper proposes F-TCP, a delay-based TCP variant, which is able to operate efficiently in high-speed networks. The slowstart phase of F-TCP continues until a threshold determined from probing the available bandwidth. When competing with loss-based flows F-TCP reduces it's window to a value derived from the available...
We study three scheduling problems (file redistribution, independent tasks scheduling and broadcasting) on large scale heterogeneous platforms under the Bounded Multi-port Model. In this model, each node is associated to an incoming and outgoing bandwidth and it can be involved in an arbitrary number of communications, provided that neither its incoming nor its outgoing bandwidths are exceeded. This...
The cognitive radio networks or CogNets poses several new challenges to the transport layer protocols, because of many unique features of cognitive radio based devices used to build them. CogNets not only have inherited all features of wireless networks, but also their link connections are intermittent and discontinuous. Exiting transport layer protocols are too slow to respond quickly for utilizing...
High-performance sockets implementations such as the Sockets Direct Protocol (SDP) have traditionally showed major performance advantages compared to the TCP/IP stack over InfiniBand (IPoIB). These stacks bypass the kernel-based TCP/IP and take advantage of network hardware features, providing enhanced performance. SDP has excellent performance but limited utility as only applications relying on the...
Worldwide Interoperability for Microwave Access (referred to as WiMAX) is a MAC and physical layer wireless communications technology for outdoor broadband wireless coverage. In collaboration with the Clemson University Police Department, we have deployed an 802.16d WiMAX network that operates at 4.9 GHz at Clemson University. In this paper, we present the results from a performance analysis we have...
We propose a prefetching mechanism at the iSCSI initiator to improve the memory cache hit rate and attain better bandwidth utilization. By monitoring the scheduler run queue, the iSCSI initiator is able to move pages to the iSCSI initiator memory cache from the iSCSI target before a page fault occurs. To increase the effectiveness of prefetching, a small striped disk is used to keep more copies of...
Layered streaming can be used to adapt to the available download capacity of an end-user, and such adaptation is very much required in real world HTTP media streaming. The multiple layer codec has become more refined, as SVC (the scalable extension of the H.264/AVC standard) has been standardized with a bit rate overhead of around 10% and an indistinguishable visual quality, compared to the state...
This paper presents a novel transport protocol, CUSP, specifically designed with complex and dynamic network applications in mind. Peer-to-peer applications benefit in particular, as their requirements are met by neither UDP nor TCP. While other modern transports like SCTP or SST have also tried to combine the advantages of TCP and UDP, CUSP overcomes their technical and conceptual shortcomings. CUSP...
This paper presents a novel scheme, Layered Internet Video Engineering (LIVE), in which network nodes feedback virtual congestion levels to video senders to assist both media-aware bandwidth sharing and transient loss protection. The video senders respond to such feedback by adapting the rates of encoded H.264/SVC streams based on their respective video rate-distortion (R-D) characteristics. The same...
In recent years high performance computing has evolved from large and expensive supercomputers to network based environments or workstation clusters and to grid computing. A grid is composed by geographically sparse resources that join to form a virtual computer. The resources (computers, networks, storage devices, etc.) of the grid are heterogeneous and reside in differentiated domains. An important...
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