INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING Int. J. Satell. Commun. Network. (in press) Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/sat.855 Transport layer protocols and architectures for satellit (original) (raw)
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Transport layer protocols and architectures for satellite networks
International Journal of Satellite Communications and Networking, 2007
Designing efficient transmission mechanisms for advanced satellite networks is a demanding task, requiring the definition and the implementation of protocols and architectures well suited to this challenging environment. In particular, transport protocols performance over satellite networks is impaired by the characteristics of the satellite radio link, specifically by the long propagation delay and the possible presence of segment losses due to physical channel errors. The level of impact on performance depends upon the link design (type of constellation, link margin, coding and modulation) and operational conditions (link obstructions, terminal mobility, weather conditions, etc.). To address these critical aspects a number of possible solutions have been presented in the literature, ranging from limited modifications of standard protocols (e.g. TCP, transmission control protocol) to completely alternative protocol and network architectures. However, despite the great number of different proposals (or perhaps also because of it), the general framework appears quite fragmented and there is a compelling need of an integration of the research competences and efforts. This is actually the intent of the transport protocols research line within the European SatNEx (Satellite Network of Excellence) project. Stemming from the authors' work on this project, this paper aims to provide the reader with an updated overview of all the possible approaches that can be pursued to overcome the limitations of current transport protocols and architectures, when applied to satellite communications. In the paper the possible solutions are classified in the following categories: optimization of TCP interactions with lower layers, TCP enhancements, performance enhancement proxies (PEP) and delay tolerant networks (DTN). Advantages and disadvantages of the different approaches, as well as their interactions, are investigated and discussed, taking into account performance improvement, complexity, and compliance to the standard semantics. From this analysis, it emerges that DTN architectures could integrate some of the most efficient solutions from the other categories, by inserting them in a new rigorous framework. These innovative architectures therefore may represent a promising solution for solving some of the important problems posed at the transport layer by satellite networks, at least in a medium-tolong-term perspective.
Advanced transport satellite protocol
2012 IEEE Global Communications Conference (GLOBECOM), 2012
Mitigation of Transmission Control Protocol (TCP) performance degradation over satellite has been extensively studied over the last two decades by the scientific community, which has come up with a large set of protocol and architecture solutions. This paper proposes a novel end-to-end (E2E) transport layer protocol, namely Advanced Transport Satellite Protocol (ATSP), which is built around consolidated control theory concepts already infused in Active Queue Management (AQM) control schemes. ATSP exploits the knowledge of the bandwidth allocated to each terminal, as available from the satellite network operator. Besides, the satellite network property of being completely under control allows the joint collaboration of sender, receiver and routers in order to acquire a complete knowledge of the network status and eventually optimize the overall performance. The performance analysis shows that ATSP achieves a fair bandwidth share for all the satellite users and outperforms TCP Hybla, which is optimized for satellite links, in terms of throughput.
Transport Protocol and Resource Management for Satellite Networks: Framework of a Project
The paper describes the protocol definition within the framework of the Project "Transport Protocol and Resource Management for Mobile Satellite Networks", funded by the European Space Agency ESA) and carried out by an Italian group composed of Marconi Mobile, CNIT and Etnoteam. In more detail, the Project is aimed at designing, implementing and testing a protocol stack adapted to the specific characteristics of a satellite communications system. The protocol stack is based on the TCP/IP suite adapted to the channel characteristics. The objective is the optimization of both the transport protocol performance for a satellite network environment and the efficient utilization of network resources. This has been achieved without re-designing the protocol interfaces, so that they will keep the same characteristics of the interfaces currently used. These characteristics should get the target of maximizing the system performance and, in the same time, allow the utilization of sta...
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The design of efficient communication mechanisms for small satellite networks is a challenging task, requiring the definition and implementations of specific protocols and architectures appropriate to space's critical conditions. In this paper, we have selected XSTP (eXtended Satellite Transport Protocol) as candidate protocol for nanosatellite networks. Foremost, we implement XSTP in NS-2 simulator. The initial simulations were done in a LEO satellite network scenario. According to our simulations, XSTP was shown to attain higher effective throughput, much lower overhead, and better channel efficiency as compare to TCP clones, in case of high BER conditions. As to low BER environment, all protocols have a comparable performance in terms of channel efficiency.
PETRA: Performance Enhancing Transport Architecture for Satellite Communications
IEEE Journal on Selected Areas in Communications, 2004
This paper presents a performance enhancing transport architecture for the satellite environment. This solution improves the network transport performance by overcoming the limits imposed by a transmission control protocol/Internet protocol (TCP/IP)-based stack suite, while maintaining the interfaces offered by it. This is an important issue since TCP/IP is widely used and most of the applications are based on it. The work starts from the state-of-the-art about the transport layer over satellite by distinguing two alternative frameworks: the black box (BB) and the complete knowledge (CK) approaches. In the former, the network is considered as a "black box" and only modifications in the terminal tools are permitted. In the latter, the complete control of any network element is allowed so as a performance optimization procedure is possible. The proposed architecture [called Performance Enhancing Transport Architecture (PETRA)] is designed in all details using the second approach. PETRA uses network elements, called relay entities, to isolate the satellite portions in case of heterogeneous networks, while a transport layer protocol stack is used to optimize the transport of information over satellite links. A special satellite transport protocol, that is part of the transport layer protocol stack, is used over such links to perform error recovery. Simulation results show that the proposed framework significantly enhances throughput performance.
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Current TCP Protocols have lower throughput performance in satellite networks mainly due to the effect of long propagation delays and high link error rates. In this paper a new congestion control protocol for satellite networks is proposed. The protocol uses a proactive approach and is composed of novel ideas like Proactive Slow Start, Proactive Congestion Avoidance and Decision based Error handling policies that are combined with traditional TCP algorithms like Fast Retransmit. The mainstay of our protocol is that the nature of the RTT pattern can give us probable indication of an incipient congestion in the network. This changing pattern of RTT is incidentally used to differentiate between congestion or link error, thus avoiding unnecessary rate throttle. In the initial phase necessary augmentation of ns2 simulator pertaining to the proposed protocol is carried out. This was essential to create a necessary test bed for exhaustive simulation of the protocol considering a GEO networ...
TRANSPORT PROTOCOL SUPPORT FOR AERONAUTICAL SATELLITE
2004
We recommend suitable transport protocols for an aeronautical network supporting Internet and data services via satellite. We study the characteristics of an aeronautical satellite hybrid network and focus on the problems that cause dramatically degraded performance of the Transport Protocol. We discuss various extensions to standard TCP that alleviate some of these performance problems. Through simulation, we identify those TCP implementations that can be expected to perform reasonably well. Based on the observation that it is difficult for an end-to-end solution to solve these problems effectively, we propose a new TCP-splitting protocol, termed Aeronautical Transport Control Protocol (AeroTCP). The main idea of this protocol is to use a fixed window for flow control and one duplicated acknowledgement (ACK) for fast recovery. Our simulation results show that AeroTCP can maintain higher utilization for the satellite link than end-to-end TCP, especially in high BER environment.
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IET Conference Publications, 2009
The ever growing use of Internet applications (e.g., email, file transfer, remote access and web browsing) is causing progressive congestion of telecommunication networks.