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Enhancing TCP Over Satellite Channels Using Standard Mechanisms
Abstract
The Transmission Control Protocol (TCP) provides reliable delivery of data across any network path, including network paths containing satellite channels. While TCP works over satellite channels there are several IETF standardized mechanisms that enable TCP to more effectively utilize the available capacity of the network path. This document outlines some of these TCP mitigations. At this time, all mitigations discussed in this document are IETF standards track mechanisms (or are compliant with IETF standards).
... Затем алгоритм быстрого восстановления управляет восстановлением данных до тех пор, пока не будет подтвержден последний переданный сегмент при входе в режим быстрой повторной передачи. Этот аспект в основном отличает TCP Reno и NewReno (стандарт описан в 2004 г.) от TCP Tahoe и Old Tahoe (алгоритм управления потоком, ранний ва- (4) риант TCP) [12]. Алгоритмы быстрой повторной передачи и быстрого восстановления обычно реализуются вместе (TCP Reno) следующим образом: ...
... Протокол TCP Hybla [4,31] был задуман с целью противодействия ухудшению производительности, вызванного длительным RTT, типичным для спутниковых соединений. Протокол состоит из набора процедур, которые включают: усовершенствование стандартных алгоритмов управления перегрузкой как для фаз медленного запуска, так и для фазы предотвращения перегрузки, обязательное принятие принципа SACK, принятие оценки пропускной способности канала, использование временных меток и реализация методов разделения пакетов. ...
... Другие кривые TCP NewReno показывают зависимость производительности от RTT. Конечно, выбор «правильного» значения для RTT 0 для TCP Hybla может быть проблемой, по крайней мере, в открытых сетях, где задержки на пути наземных соединений значительно различаются [4]. ...
This is a systematic review of modern and promising network protocols of the transport layer in digital satellite communication systems. The specificity of satellite communications consists in rather large delays in data transmission due to the long distances and high-energy flows (interference). Therefore, the study pays special attention to the organization of efficient data transmission in networks containing satellite segments, as well as highlights approaches to the development of new solutions based on traditional network protocols. The interaction of the TCP protocol with the protocols of the underlying layer is described. The analysis of protocols with architecture inherited from TCP is carried out: TCP Peach, TCP Westwood, TCP Hybla, CK-STP, SCTP. Modern ways to improve the performance of the TCP protocol are described. Promising protocols for use in satellite communication systems (QUICK, STEP, STP) are described.
... We conclude that TCP is entirely capable of running on IEEE 802. 15.4 networks and low-cost embedded devices in LLN application scenarios ( §9). Since our improvements to TCP and the link layer maintain seamless interoperability with other TCP/IP networks, we believe that a TCP-based transport architecture for LLNs could yield considerable benefit. ...
... Since the introduction of TCP, a vast literature has emerged, focusing on improving it as the Internet evolved. Some representative areas include congestion control [9,51,62,76], performance on wireless links [15,27], performance in highbandwidth environments [11,30,53,65,78], mobility [124], and multipath operation [115]. Below, we discuss TCP in the context of LLNs and embedded devices. ...
... Although the term LLN can be applied to a variety of technologies, including LoRa and Bluetooth Low Energy, we restrict our attention in this paper to embedded networks using IEEE 802. 15 [77], Wi-Fi [27], cellular [25,100], and satellite [15,25] links. While an 802.15.4 radio can in principle be added as a NIC to any device, we consider only embedded devices where it is the primary means of communication, running operating systems like TinyOS [68], RIOT [24], Contiki [45], or FreeRTOS. ...
Low-power and lossy networks (LLNs) enable diverse applications integrating many resource-constrained embedded devices , often requiring interconnectivity with existing TCP/IP networks as part of the Internet of Things. But TCP has received little attention in LLNs due to concerns about its overhead and performance, leading to LLN-specific protocols that require specialized gateways for interoperability. We present a systematic study of a well-designed TCP stack in IEEE 802.15.4-based LLNs, based on the TCP protocol logic in FreeBSD. Through careful implementation and extensive experiments , we show that modern low-power sensor platforms are capable of running full-scale TCP and that TCP, counter to common belief, performs well despite the lossy nature of LLNs. By carefully studying the interaction between the transport and link layers, we identify subtle but important modifications to both, achieving TCP goodput within 25% of an upper bound (5-40x higher than prior results) and low-power operation commensurate to CoAP in a practical LLN application scenario. This suggests that a TCP-based transport layer, seamlessly interoperable with existing TCP/IP networks, is viable and performant in LLNs.
... However, to achieve optimum performance and effective utilisation of available capacity of SatCom and hybrid ISTN, there is a need to address performance problems which lead to underutilisation, degraded Quality of Service (QoS) and poor Quality of Experience (QoE). These problems are associated with the widely used/de-facto data Transmission Control Protocol over the Internet Protocol (TCP/IP) network environment, which could involves a satellite channel [10]. [5] Originally, the TCP design concepts were first described in [11], to be connection-oriented and end-to-end (E2E) reliable, and fitting into a layered hierarchy architecture of the IP and supporting multi-network applications [12]. ...
... Today, TCP has become the most widely used data transport protocol over IP (TCP/IP), which transports 80-90% Internet traffic [14]- [18]. However, emerging and evolving network technologies characterised by high-speed (Bandwidth/Capacity) and long distance networks with long Round-Trip-Time (RT T ) such as satellite, and wireless links with high link errors introduced new challenges to the performance of TCP, which led to underutilisation of the available capacity [10,19]. The effective performance of TCP depends on the product of the transfer rate and RT T known as Bandwidth-Delay Product (BDP ), which is directly linked to the available capacity [20]. ...
... Reliable Internet data delivery across any E2E network path can be achieved using de-facto TCP; this includes a hybrid ISTN path. However, the key attributes of Satellite links such as long RT T , high error rates, and high BDP , particularly the GEO HTS, present a serious negative impact on the performance and behaviour of TCP-based transport protocols, posing challenges to Internet connectivity [10,21]. This performance degradation leads to low channel capacity utilisation of the satellite channel's extreme capacity. ...
... However, it is well-known that TCP performance is limited over satellite links. The performace is limited due to the long propagation delays and the congestion control features together with the slow-start mechanism of TCP, Allman et al. (2020) (accessed December 2, 2020. Therefore, several extensions to TCP have been developed that are known as "TCP acceleration features" and which are usually implemented in the satellite modem as the interface between the satellite and terrestrial network. ...
... However, it is well-known that TCP performance is limited over satellite links. The performace is limited due to the long propagation delays and the congestion control features together with the slow-start mechanism of TCP, Allman et al. (2020) (accessed December 2, 2020. Therefore, several extensions to TCP have been developed that are known as "TCP acceleration features" and which are usually implemented in the satellite modem as the interface between the satellite and terrestrial network. ...
5G New Radio (NR) is the 3rd Generation Partnership Project (3GPP) radio access technology for the next generation mobile communications network. A major evolution of 5G constitutes the integration of non-terrestrial networks including geostationary and low Earth orbit satellites. The seamless integration of satellites in the terrestrial mobile network requires significant adaptations within the radio access network and the development of new features in the core network to cope with the specific satellite channel characteristics. To date, the 5G control and data plane has been standardized to handle only continuous backhaul communication between the network components. However, a mobile satellite enabled next generation Node B (gNB) located in a vehicle or in a moving aerial platform needs to be able to handle frequent backhaul outages of various duration as well as longer signal delays as opposed to short terrestrial connections via fiber. In this paper, we report the results of an over-the-air (OTA) field trial comprising a mobile edge node connected to the 5G standalone core network components over a geostationary satellite. We analyze Transmission Control Protocol (TCP) acceleration and GPRS Tunneling Protocol (GTP)/TCP/Internet Protocol (IP) header compression features through the GTP. Moreover, the influence of short and long interruptions in the communication between the edge node and the central components on the entire system performance is investigated. The header compression and TCP acceleration modules were implemented on the satellite modems and are now part of the protocol stack of these devices. The results show up to 12% higher data rates for the 5G user equipment (UE), on a 1.5 MHz single carrier return link compared to deactivated TCP acceleration and header compression. We increased the data rate by 20% on the 4.5 MHz DVB-S2X forward link between the UE and 5G core. Moreover, our measurements reveal that even satellite-enabled gNB mobility is possible with the current Release 15 standard. After a short outage of the satellite connection due to shadowing, the UE can successfully re-establish the user plane connection to the core network. Our results will facilitate the full integration of satellite components in 5G through open and standard solutions.
... One example of this is the problems related to TCP on-top of IP. This topic has been addressed several times, for example in RFC2488 [144]. The long delay present in satellite networks impacts how acknowledgments are handled, and if the transmitting node does not receive the acknowledgment within the defined timeout, the TCP protocol at the transmitter will interpret this as network congestion or erroneous transmission of a link-layer frame. ...
... New IoT protocols are designed for networks with low data rates and where the link availability is not constant. These implement functionality that helps the already stated short-comings of, for example, TCP [142,144,145]. Proposed protocols, implications and implementations are discussed further in the papers [116,117]. ...
The Arctic and space are concepts that fascinate us. Both places seem remote and hostile, but are at the same time beautiful and exciting. Together, they form a part of the world comprised of daring challenges, but also of endless possibilities for science, recreation, wonder, knowledge and inspiration.
Several scientists would like access to more and frequently updated information about the Arctic area. Today, no adequate communication systems allowing this exists. Due to this, access to sensor data is often limited to traveling to the sensor node and retrieve its data.
This thesis aims to bridge parts of the Arctic and space. The work in this system study may bring the Arctic nearer to us by proposing a space communication system that can connect assets in the Arctic with people residing in less remote areas.
The main research motivation was to investigate if a system of small satellites could be a viable solution to bridge the communication gap in the Arctic. An important use case is to enable access to sensor data from sensors deployed in remote locations without having to physically be at the node to download the data. The main findings show that this can be possible, by establishing a communication system with small satellites. The small satellites have their challenges and limits, but by careful design, a system can be made to compare with other solutions, both in utility and cost.
The main contribution from this work is the proposal on how to use a freely flying swarm of small satellites to provide good and frequent coverage, without having to use satellites with propulsion systems. This saves component cost, mass and volume, which in turn contribute to a reduced launch cost. The deployment of a satellite swarm seems feasible both from a technical point of view, as well as from an economical point of view.
The coverage property for a swarm is not constant, and on average it is not as good as coverage by a constellation consisting of the same number of satellites. However, for services that do not require to transmit time-critical sensor data, this is of less concern and variations in responsiveness can be accepted.
Another contribution is a system study on how a heterogeneous communication architecture can be designed, ensuring interoperability between satellites, sensor nodes and unmanned vehicles. Different networks may be interconnected and joined, providing connectivity between sensor systems and operators through the Internet. This interconnection can be made possible by the use of standard Internet-of-Things protocols. These networks can consist of local networks linking sensor nodes, satellite links between sensor nodes, satellites and gateway stations, as well as other types of unmanned or manned vehicles acting as data mules; ferrying data from one part of the network to another.
A central topic of investigation in any radio communication system is the link budget. By carefully evaluating the various contributing factors of the link budget, a feasible budget is presented. However, some assumptions are required. In order to design a system with a usable data rate, the satellite must be designed to compensate for some of the limitations of a typical sensor node. A system supporting an even higher data rate also requires the sensor node to be equipped with a high-gain antenna. This represents an interesting research topic for further study.
The cost of the space segment is also evaluated against the use of unmanned aerial vehicles and airplanes. From this analysis, it is shown that a satellite system will provide a more continuous coverage, being able to transmit a comparable amount of data, at a similar or lower cost. The satellites could be based on Cube-Sats.
To conclude, the outcome of this study shows that a dedicated satellite system, your mission, your satellite(s), can be a viable solution to the challenge on how to relay sensor data from the Arctic to scientists at home. The work follows the early phases of established space mission analysis and design methods.
... In fact, there are so many different aspects to Internet mobility that no single journal issue or book could possibly describe all of them. Thus, we will have to be content with presenting a representative selection of articles that, in their diversity, give a good hint at the larger picture [1][2][3][4][5]. At the same time, these articles pro-vide new directions and lead the way towards solving the interesting and new problems raised by mobility. ...
... When the asymmetry is too great, the mobile node cannot supply ACKs back to the source of TCP data fast enough, and the supply of data to the down-link operates at far below capacity. Most solutions to this problem require changes to the Internet node providing data to the mobile node [2]. As with route optimization, solu-tions in this class will take a long time to deploy, and will probably only happen as satellite communications become important for the general operation of the Internet. ...
Computers capable of attaching to the Internet from many places are likely to grow in popularity until they dominate the population of the Internet. Consequently, protocol research has shifted into high gear to develop appropriate network protocols for supporting mobility. This introductory article attempts to outline some of the many promising and interesting research directions. The papers in this special issue indicate the diversity of viewpoints within the research community, and it is part of the purpose of this introduction to frame their place within the overall research area.
... In fact, there are so many different aspects to Internet mobility that no single journal issue or book could possibly describe all of them. Thus, we will have to be content with presenting a representative selection of articles that, in their diversity, give a good hint at the larger picture [1][2][3][4][5]. At the same time, these articles pro-vide new directions and lead the way towards solving the interesting and new problems raised by mobility. ...
... When the asymmetry is too great, the mobile node cannot supply ACKs back to the source of TCP data fast enough, and the supply of data to the down-link operates at far below capacity. Most solutions to this problem require changes to the Internet node providing data to the mobile node [2]. As with route optimization, solu-tions in this class will take a long time to deploy, and will probably only happen as satellite communications become important for the general operation of the Internet. ...
Computers capable of attaching to the Internet from many places are likely to grow in popularity until they dominate the population of the Internet. Consequently, protocol research has shifted into high gear to develop appropriate network protocols for supporting mobility. This introductory article attempts to outline some of the many promising and interesting research directions. The papers in this special issue indicate the diversity of viewpoints within the research community, and it is part of the purpose of this introduction to frame their place within the overall research area.
... When both UEs are active, the resources are shared fairly, and both users are served with equal goodput. Compared to UDP, we observe that the slowstart mechanism of TCP [18] affects the two UEs connected via the satellite channel emulator. ...
... There have been decades of improvements and optimizations at the transport layer to make TCP perform better in large-BDP settings within TCP itself [2,15,17,33], while others concern operating system support for TCP [20,24,48]. Improvements to TCP are complementary to Skyplane. ...
Cloud applications are increasingly distributing data across multiple regions and cloud providers. Unfortunately, wide-area bulk data transfers are often slow, bottlenecking applications. We demonstrate that it is possible to significantly improve inter-region cloud bulk transfer throughput by adapting network overlays to the cloud setting -- that is, by routing data through indirect paths at the application layer. However, directly applying network overlays in this setting can result in unacceptable increases in cloud egress prices. We present Skyplane, a system for bulk data transfer between cloud object stores that uses cloud-aware network overlays to optimally navigate the trade-off between price and performance. Skyplane's planner uses mixed-integer linear programming to determine the optimal overlay path and resource allocation for data transfer, subject to user-provided constraints on price or performance. Skyplane outperforms public cloud transfer services by up to $4.6\times$ for transfers within one cloud and by up to $5.0\times$ across clouds.
... While supervised learning includes semi-supervised learning like graph neural network(GNN), recurrent neural network(RNN) and Long-short Term Network(LSTM). And the target is trying to resolve the object segmentation, object detection and human pattern recognition, like house riding [3] position w/o coverage, or human position recognition [6]. ...
Current human behaviour recognition are the most foundational task of computer vision. With the current research analysis, there are some major techniques are widely used by the industry area and research fields. The segments(frames) works as the unit of analysis. Video Human Behaviour Recognition(VHBR) works as a branch of human behaviour analysis which provides possibility of content detection and analysis.This paper addresses multiple current research works and does the comparison between the variants of these algorithms. The target is getting the overview of Video Human Behaviour Recognition(VHBR) methodologies and gave the prediction or the further trend of development. There has been plenty of methodologies have investigated the VHBR with reaching the high accuracy and it has been manipulated into various perspective of application, such as health care, education and technique advancement. Based on the current research work, there are plenty of research work is basing on spatial-temporal sequences analysis of video, but less of them are related to the forehead behaviour detection for preventing unpredictable damage for society.
... Scholars have conducted considerable work to improve the performance of satellite networks. The Internet Engineering Task Force suggested that the congestion window be increased from one segment to four maximum segments or 4380 bytes [4][5][6], but the performance of this approach still needs further improvement. The new cross-layer approaches based on the fast-start mechanism and reducing the time of slow-start and congestion avoidance phases can also reduce the impact of long latency in satellite networks [7][8][9][10], but the performance enhancement of satellite networks for long latency is still worth exploring. ...
The high-speed broadband access technology of satellite networks is becoming increasingly mature, but high-capacity data transmission is prone to congestion, which greatly affects the transmission impact of geostationary orbit (GEO) satellite networks. To alleviate the congestion in satellite networks and improve the transmission rate of links, this study proposed a scheme to increase the data transmission volume. The impact of long delay and high bandwidth in satellite networks was mitigated by increasing the congestion window on the sender side, and increasing the number of data transmissions ensured that the proposed scheme fully utilized the high bandwidth delay product of satellite networks. Different types of data loss were used to improve the stability of network transmission. Results show that the proposed scheme can significantly improve the throughput and reduce the response time of a satellite link when a satellite network is congested. The scheme also significantly improves the network performance when the satellite network is not congested. When the network is not congested, the proposed scheme improves the throughput by a factor of 6 over the standard protocol. Even in the case of congestion, the former also improves the throughput by a factor of 2 over the latter. The proposed method provides a useful reference for improving the transmission performance of satellite networks.
... Undesirable delay affects the use of the TCP (Transmission Control Protocol) /IP (Internet Protocol) protocol stack, which was developed for low delay and low bit error rate terrestrial links [25,33,36,37]. It is difficult to use in both network and transport layers [2]. Information on this will be presented in the next section. ...
Satellites are the transmission medium for providing connectivity and building global, continental, or regional networks around the world (satellite operators effectively use satellites to support Internet traffic), and point-to-point connections are also possible. In practical use, there are combinations of VSAT networks with terrestrial wireless extensions, allowing end users to increase the capabilities offered via satellite. This paper provides selected information on broadband satellite networks using VSAT technology, including available protocols and transmission platforms. The aim of the article is also to present the chosen technical aspects of satellite networks working with the usage of VSAT technology.
... e original design of TCP protocol is used for terrestrial wired networks, and it has been proved to be very successful for supporting Internet data communications for decades. However, there are several factors that decrease the performance of the TCP over satellite networks [2][3][4][5]. Firstly, due to the ultralong distance of GEO satellite link, there will inevitably appear high delay phenomenon in data transmission. ...
The geostationary (GEO) satellite networks have two important influencing factors: high latency and transmission errors. Similarly, they will happen in the large-scale multihop network of the Internet of things (IoT), which will affect the application of 5G-(5th-generation mobile networks-) IoT. In this paper, we propose an enhanced TCP mechanism that increases the amount of data transferred in the slow start phase of TCP Hybla to mitigate the effect of long RTT and incorporates a refined mechanism of TCP Veno, which can distinguish packet loss between random and congestion. This scheme is evaluated and compared with NewReno, Hybla, and Veno by simulation, and the performance improvement of the proposed TCP scheme for GEO satellite network in the presence of random packet losses is demonstrated. At the same time, the enhanced TCP scheme can improve the transmission performance in the future 5G-IoT heterogeneous network with high delay and transmission.
... Small buffers can limit the achieved data rate below the available link capacity, according to the implemented loss recovery algorithm; large buffers can lead to a significant increase of the end-toend latency well above the transmission delay, with a negative impact on both the delay-sensitive applications and the overall fairness among competing flows. Moreover, high RTT can slow down the rate increase process, leading to very inefficient network utilization [1]. Examples of CCAs based TCPs are NewReno [2] and Cubic [3]. ...
TCP Wave relies on a disruptive communication paradigm based on bursts, to overcome limitations of legacy TCP with modern applications and challenging network scenarios. This protocol was already validated with appealing results via simulations. This work now presents its implementation in the Linux kernel, focusing on the adaptations needed to deal with real networking systems. A Linux implementation paves the way to validate the protocol algorithms and working principles on real communication environments, thus drawing its operational perimeter. In this regard, the most ambitious goal is to show the bright side of the burst transmission as a novel opportunity for performance optimization in the future Internet connectivity scenarios. TCP Wave performance is therefore compared with reference TCP congestion schemes currently included in the Linux kernel, namely BBR and Cubic, under a large set of network configurations. A vast gamut of performance indicators are presented and discussed, including throughput, latency, fairness, friendliness, loss management and reaction to network and traffic changes. Definitely, this paper is a manifest for the real TCP Wave implementation in Linux, which can act as reference for future works.
... TCP Lite removes part of the session control information to reduce the data to be sent [16]. TCP Sat is used to overcome the drawbacks of a standard TCP protocol in satellite networks over terrestrial networks [14]. Current research is also focused on incorporating machine learning via neural networks to better predict network congestion and appropriately modulate the congestion window to reduce the conservative nature of currently available congestion control algorithms [15]. ...
... TCP Lite removes part of the session control information to reduce the data to be sent [16]. TCP Sat is used to overcome the drawbacks of a standard TCP protocol in satellite networks over terrestrial networks [14]. Current research is also focused on incorporating machine learning via neural networks to better predict network congestion and appropriately modulate the congestion window to reduce the conservative nature of currently available congestion control algorithms [15]. ...
... TCP is network aware communication protocols mainly develop for transferring data packets on Internet securely. TCP is the basic means to carry data over Internet Protocol (IP) reliably, because in TCP, a connection is established first before sending data, thus TCP is a connection-oriented protocol [3]. ...
Flow control, end-to-end (EED) delay, throughput, and energy consumptions are important factors of real-time and multimedia communication in mobile ad-hoc networks (MANET’s). It has a characteristic of the dynamic flow of data communication among the various users without using wired technologies. Due to this dynamic structure of MANNETS, most of its energy is consumed in route searching and packet retransmission. In addition, a problem of energy consumption may also occur due to network congestion and traffic flow control. In general, UDP is used for real-time communication but this protocol is unable to control the traffic flow properly. Therefore, a new protocol is developed for this purpose called datagram congestion control protocol (DCCP) used in those networks, which has an increasing number of multimedia traffic, and real-time flow. In this research work, major performance metrics with the issue of power usage of the TFRC and TCP like DCCP protocols are evaluated.
... It is well-known that classic versions of the TCP protocol may have low performance in terms of throughput over GEO satellite links [2] due to: (i) high propagation delays, which entail a slow increase in the congestion window (cwnd), regulating the amount of data injected in the network; (ii) possible frequent errors in the radio channel, which cause halving cwnd [3], in that TCP assumes that packet losses are due to congestion. Excessive delays in correctly transmitting a packet (a "segment", in TCP terminology), due to bad channel conditions, may entail a TCP time-out, thus forcing TCP to reduce cwnd to the minimum value (one or two segments in most cases). ...
The adoption of satellite systems in providing broadband transmissions to mobile users such as trains, buses and vans is expected to be an interesting solution. The scenariowe considered refers to a hybrid network architecture, where a geostationary satellite forward link and a terrestrial 3G return link are used in order to exploit both the high bandwidth of a satellite channel and the lower propagation delay of a terrestrial path. The resulting round-trip delay is much shorter than that one experienced by using both the forward and return link via satellite. This is particularly appealing for overcoming the TCP efficiency degradation in high delay-bandwidth product and error prone channels. In this hybrid scenario, we used simulation results to compare the goodput of four of the most popular TCP variants, in the presence of a GOOD-BAD satellite channel, as the one experienced by mobile users. We applied an AdaptiveCoding and Modulation (ACM) technique as well, and studied its impact on TCP efficiency, when used both alone and in cooperation with an Automatic Repeat reQuest (ARQ) scheme of the Selective Repeat (SR) type with low persistency. Results obtained indicate that this hybrid architecture is advantageous for TCP transmissions in terms of average goodput, and that ACM is effective only if it is jointly used with ARQ schemes.
... However, TCP performance degrades in geostationary satellite networks due to long propagation delays and high bit error rates. In recent years, many of scholars propose a number of solutions for improve TCP performance in satellite networks [1][2][3][4]. The proposed solutions can be roughly divided into the following three categories: end-to-end improvement solutions [5], TCP split connection solutions [6] and delay tolerant networks (DTN) solutions [23]. ...
TCP performance is essential for data transmissions over the satellite network. The TCP ADaLR is congestion control algorithm that the sender judgments the relevant window change and measures round-trip time to control congestion window. It can adapt to the characteristics of the satellite link and improve the performance of TCP than conventional TCP (New Reno). However, it doesn’t take into account distinction of random packet loss and congestion packet loss like the TCP Veno. In this paper, we propose further enhancement scheme of TCP ADaLR, called TCP ADaLR+, which can distinguish between random packet loss and congestion loss. The improved performance of proposed TCP ADaLR+ is demonstrated by simulations. In all simulation scenarios, TCP ADaLR+ outperforms TCP ADaLR and TCP Veno in terms of satellite link throughput and FTP download response time.
... Besides CR networks, there are other networks where the links can be modeled as ON-OFF channels. Intermittent loss of connectivity also happens in cellular networks due to hand-offs, in mobile ad-hoc networks [5] due to link failures, in satellite networks [6] and in 802.11 networks due to collisions. ...
In this paper, we study the performance of a TCP connection over cognitive radio networks. In these networks, the network may not always be available for transmission. Also, the packets can be lost due to wireless channel impairments. We evaluate the throughput and packet retransmission timeout probability of a secondary TCP connection over an ON/OFF channel. We first assume that the ON and OFF time durations are exponential and later extend it to more general distributions. We then consider multiple TCP connections over the ON/OFF channel. We validate our theoretical models and the approximations made therein via ns2 simulations.
... The approach of opening multiple connections over a single physical link to overcome the limitation of terrestrial protocols in high speed wide area network and satellite-based environment has been suggested by the authors of Allman et al. (1999), Ostermann et al. (1996), Lannucci and Leakashman (1992), Fu et al. (2007) and Sivakumar et al. (2000). However, to the best of our knowledge, no quantitative investigation has been done till date to evaluate the performance enhancement of these protocols in deep space communications, specifically in MARS exploration networks (for which a lot of activities can be seen in recent times). ...
... Special consideration should be paid to the receiver sending delayed ACKs as explained in 12 . In comparison with GEO satellite systems, LEO constellations face delay-variations whose impact on TCP performance is currently a great issue 10 . he slow start phase unwantedly spoils a lot of time during the time of connection establishment. ...
Objective: In this world of advanced technology, satellite communication is the basis for all data communications. TCP was designed to be flexible and robust but it cannot perform efficiently over the satellite links with long delay. The major objective of our work is to propose a novel flow control algorithm for satellite network to prevent the heavy degradation in the network performance due to long propagation delay, high bit error rate and bandwidth asymmetry. Methods: A strong flow control mechanism is necessary to eliminate the network performance degradation due to the satellite link characteristics like long propagation delay, high bit error rate and bandwidth asymmetry. Satellite-TCP is a flow control mechanism based on the negative acknowledgement strategy and connection splitting. The satellite link utilization is monitored and the active connections are assigned with the window values. The window values were considered as it can easily reflect the available bandwidth in the satellite links. Findings: The major problems affecting the performance in satellite links are long propagation delay, high bit error rate and bandwidth asymmetry. The proposed Flow Control Algorithm called Satellite-TCP is based on controlling the flow of Negative Acknowledgement packets (NACK), according to the level of congestion at the network. The two main modules in the proposed system include an enhanced TCP flow control mechanism and a data loss recovery mechanism. Among this the flow control is based on link utilization measurements and throughput calculation techniques. Data loss recovery strategy is based on Negative Acknowledgements coming from the receiver side. In this way, we can decrease the amount of packet loss in the network and even eliminate the packet loss, sometimes. Satellite-TCP adopts a window growth strategy to accelerate the speed of increase in the size of congestion window. The flow control mechanism not only enhanced the throughput of forward link but also greatly reduced the bandwidth occupancy rate in back-ward link in the satellite network. This in turn increases the overall performance of the satellite link. Improvements: If we add a priority based strategy to the new flow control mechanism, it can judge the network performance according to the data loss. Moreover we are expecting that, if we add a priority bit based strategy to the new flow control mechanism, it will help to distinguish the specific reasons for data loss and can take corresponding flow control strategies. While considering the throughput and loss rate, Satellite -TCP is showing excellent performance in the case of forward link but it performs poor in the case of backward link. So we are planning to extend our work in such a way that it will perform well in the case of backward link also.
The rapid growth of satellite network operators (SNOs) has revolutionized broadband communications, enabling global connectivity and bridging the digital divide. As these networks expand, it is important to evaluate their performance and efficiency. This paper presents the first comprehensive study of SNOs. We take an opportunistic approach and devise a methodology which allows to identify public network measurements performed via SNOs. We apply this methodology to both M-Lab and RIPE public datasets which allowed us to characterize low level performance and footprint of up to 18 SNOs operating in different orbits. Finally, we identify and recruit paid testers on three popular SNOs (Starlink, HughesNet, and ViaSat) to evaluate the performance of popular applications like web browsing and video streaming.
It has been forty years since TCP/IP was standardized as RFC 793. The spectacular success of the Internet has validated the design choices of its protocols and architecture. However, the evolution of the services and applications running over the Internet, new societal requirements and the general unavoidable obsolescence of any protocol will at some point require rethinking the current protocols and potentially replacing them with new ones. New technology has emerged in limited domains networks, such as data centers, that may hint at a way forward for the overall Internet architecture. We present an overview of the recent and current work on post-IP networking and discuss the drivers and motivations that will push us to reimagine IP.
The transmission of huge amounts of data generated from various sensors is the basis and prerequisite for the analysis and prediction of the marine ecosystem. The special geographical conditions of the ocean determine that its data transmission is different from the common terrestrial data transmission. In this study, a marine environmental monitoring network architecture is proposed to collect environmental data from marine ecosystems using a heterogeneous network constructed by a multi-hop network and a satellite network. Considering the characteristics of satellite networks, such as high bandwidth delay product (BDP), long latency and high bit error rate, this work proposes a transmission scheme that improves the transmission performance of Transmission Control Protocol/Internet Protocol (TCP/IP)-based Internet networks over satellite networks. The improved scheme increases the monitoring data transmission rate, distinguishes between random data loss and congested data loss, rationalizes the threshold in fast recovery, and improves the overall transmission performance of the marine environmental monitoring network. The experimental results show that the proposed scheme can greatly improve the transmission performance of the monitoring network compared with traditional transmission protocols. The network model proposed in this study makes full use of current advanced network technologies, including multi-hop networks, wireless sensor networks, and satellite networks to expand the monitoring area at sea. This study provides a useful reference for the network model and data transmission for ocean monitoring.
The communication platform in the computing field is increasing at a rapid pace. Technology is constantly budding with the materialization of new technological devices, specifically in the communication industry. The internet is expanding exponentially. Internet-enabled devices are becoming part and parcel of our daily lives. It has turned out to be almost impossible to think about the world without the internet. The internet structures might be reinforced to meet coming prerequisites in mobile communication. Congestion plays a vital role in regulating the flow of data to accelerate the exchange of data in between the wired and wireless devices. In this chapter, the authors try to highlight various network congestion techniques with their limitations proposed from time to time by various researchers. This chapter plays a vital role in highlighting the history of networking congestion detection/avoidance techniques starting from the early days of networking.
This chapter introduces the basics of network layering models and protocols used to deliver different types of service to end users. It presents the fundamental concepts of satellite network architectures where the basic characteristics of a satellite network are introduced, in terms of topology, on‐board connectivity, and types of link before a description of typical satellite network architectures, including ones that use intersatellite links. The chapter deals with issues regarding routing and switching with transparent and regenerative processing. Broadband satellite network can rely on a variety of network topologies (star, multi‐star, mesh, or hybrid star/mesh) and provide a variety of types of connectivity. It also introduces Internet Protocol (IP) networks based on digital video broadcasting via satellite (DVB‐S) and DVBRCS, and the Internet transmission control protocol, and presents its enhancements for satellite networks. The chapter provides information on IP version 6 protocol over satellite networks.
In this paper, we propose a double differential (DD) modulation technique for Low Earth Orbit (LEO) based land mobile satellite (LMS) communication to overcome the carrier frequency offset, which is an inevitable effect with the LEO satellites. The symbol error rate (SER) expressions for the considered scheme over Shadowed- Rician fading channels with phase-shift keying (PSK) constellations are presented. Since a closed-form expression cannot be derived for quadrature PSK (QPSK) and higherorder constellations, an upper bound and a lower bound of SER are derived. The error performance of the DD modulated LMS system is compared to that of coherent modulation-based and single differential modulation-based LMS systems, and a significant performance gain of the proposed DD modulation-based system is observed. Further, we have also studied the effects of elevation angle and LEO trajectory on the error performance of the considered system.
The Internet of Things (IoT) has drawn an enormous attention into the scientific community thanks to unimaginable before applications newly available in everyday life. The technological landscape behind the implied surge of automated interactions among humans and machines has been shaped by plugging into the Internet very low power devices that can perform monitoring and actuation operations through very cheap circuitry. The most challenging IoT scenarios include deployments of low power devices dispersed over wide geographical areas. In such scenarios, satellites will play a key role in bridging the gap towards a pervasive IoT able to easily handle disaster recovery scenarios (earthquakes, tsunamis, and flash floods, etc.), where the presence of a resilient backhauling communications infrastructure is crucial. In these scenarios, Direct-to-Satellite IoT (DtS-IoT) connectivity is preferred as no intermediate ground gateway is required, facilitating and speeding up the deployment of wide coverage IoT infrastructure. In this work, an in-depth yet thorough survey on the state-of-the-art of DtS-IoT is presented. The available physical layer techniques specifically designed for the IoT satellite link are described, and the suitability of both the current Medium Access Control protocol and the upper layer protocols to communicate over space links will be argued. We also discuss the design of the overall satellite LEO constellation and topology to be considered in DtS-IoT networks.
Monoqrafiya mülki aviasiyanın avtomatlaşdırılmış aeronaviqasiya HHİ sistemlərinin peyk rabitə sistemlərinə keçidi ilə əlaqədar olaraq yaranan əsas problemlərə həsr olunmuşdur.
Nəqliyyat ötürmə protokolunun yaranması və geostasionar peyk rabitə xətləri vasitəsilə aeronaviqasiya telekommunikasiya şəbəkəsinin istifadəsi məsələlri əhatəli surətdə nəzərdən keçirilmişdir. Peyk rabitə xətləri üçün tətbiqi nöqteyi-nəzərindən nəqliyyat protokollarının müxtəlif variantlarının iş prinsipləri nəzəri və eksperimental cəhətdən analiz edilmişdir.
The first book to focus on the communications and networking aspects of UAVs, this unique resource provides the fundamental knowledge needed to pursue research in the field. The team of authors covers the foundational concepts of the topic, as well as offering a detailed insight into the state of the art in UAVs and UAV networks, discussing the regulations, policies, and procedures for deployment (including analysis of risks and rewards), along with demonstrations, test-beds, and practical real-world applications in areas such as wildlife detection and emergency communications. This is essential reading for graduate students, researchers, and professionals in communications and networking.
When mobile users transmit data over heterogeneous satellite network through satellite gate- way, there are random packets losses due to bit errors on satellite links, and intermittent connectivity may also occur when the mobile users disconnect from the satellite gateway. TCP performance degrades drastically if invoking the congestion control mechanism when encountering intermittent connectivity and random losses. This paper proposes a TCP scheme, called TCP M-Veno, which incorporates the mechanism of M-TCP at the gateway to deal with the intermittent connectivity, and refines TCP Veno at TCP sender to mitigate the effects of random losses and long propagation delay. The performance improvement of our proposed TCP M-Veno is demonstrated by simulations by comparing our proposed TCP scheme to other three TCP variants, NewReno, Veno, and M-TCP.
This chapter discusses the challenges of integrating space and terrestrial systems as well as some of the unique solutions and approaches to solving those challenges. While the first satellite systems were stand-alone and akin to a private network in today’s terminology, virtually all current satellite systems are interconnected through some component of the terrestrial infrastructure, e.g., the Internet, PSTN, or private fiber. This chapter presents examples of the current challenges in integrating space and terrestrial systems by considering two satellite system classes which have unique requirements for interconnection and interoperability: the Mobile Satellite Systems (MSS) and the Broadband Satellite Systems for Internet Access.
This chapter discusses the challenges of integrating space and terrestrial systems as well as some of the unique solutions and approaches to solving those challenges. While the first satellite systems were stand-alone and akin to a private network in today’s terminology, virtually all current satellite systems are interconnected through some component of the terrestrial infrastructure, e.g., the Internet, PSTN, or private fiber. This chapter presents examples of the current challenges in integrating space and terrestrial systems by considering two satellite system classes which have unique requirements for interconnection and interoperability: the Mobile Satellite Systems (MSS) and the Broadband Satellite Systems for Internet Access.
In satellite communications, most Internet applications run over the TCP/IP protocol to deliver data to destinations over large propagation delay and wireless channel. Due to long round-trip time (RTT) and high packet error rate (PER) over satellite links creates an environment that seriously degrades the performance of TCP. A well-known solution to mitigate these issues is performance enhancing proxy (PEP) based TCP splitting. We implement PEP testbed to evaluate and discuss the issues of satellite links. According the result even though PEP improves fair throughput in presence of wired links and random packet losses, it worsens its performance in higher PER.
We compare packet delivery delays from a probabilistic analysis of a Flat and two tree-based reliable multicast protocols with simulation results of SRM, RMTP and TMTP variations. Analytical and simulation results show identical behavior with varying packet loss probabilities, number of receivers, and transmission rates. Even the absolute delays of the analytical and simulation results are almost identical which shows that carefully mathematical modelling can provide results of the same quality as simulation does.
A second focus of our work is to identify an optimal branching factor of the control tree established by tree-based reliable multicast protocols. Our analytical and simulation results show that a branching factor which is too small can significantly increase delay.
The paper suggests an experimental methodology for analysing the performance of Web File Servers in terms of throughput and Client-Server path instability. The experimental results preview the network performance for a Client user in Australia and the influence of interconnecting networks and file server traffic demand for download applications.
This chapter discusses the challenges of integrating space and terrestrial systems as well as some of the unique solutions and approaches to solving those challenges. While the first satellite systems were stand-alone and akin to a private network in today’s terminology, virtually all current satellite systems are interconnected through some component of the terrestrial infrastructure: e.g., the Internet, PSTN, or private fiber. This chapter presents examples of the current challenges in integrating space and terrestrial systems by considering two satellite system classes which have unique requirements for interconnection and interoperability: the Mobile Satellite Systems (MSS) and the Broadband Satellite Systems for Internet Access.
It is commonly perceived that Internet applications, especially those based on TCP protocol, do not perform well over satellite networks. The root of this problem is the latency incurred in a satellite link. To stay competitive, the satellite industry has developed and deployed a practical solution, called TCP Performance-Enhancement Proxy (as known as “TCP Spoofing”) to solve this problem. Although it has gained tremendous success in today’s satellite networks, its use has always been controversial among the Internet community. Its critics blast it for breaking the end-to-end principle, an orthodox of the Internet. Lately, the increasingly pervasive IPsec applications have begun to threaten the performance of satellite networks by rendering TCP Performance-Enhancement Proxy useless for IPsec-protected traffic.
Introduction QoS concepts and standards IETF multimedia protocols Semantic approach for QoS management in home networks Conclusion Bibliography
This document specifies an increase in the permitted initial window for Transmission Control Protocol (TCP) from one segment to roughly 4K bytes. This document discusses the advantages and disadvantages of such a change, outlining experimental results that indicate the costs and benefits of such a change to TCP.
This paper considers the potentially negative impacts of an increasing deployment of non-congestion-controlled best-effort traffic on the Internet. These negative impacts range from extreme unfairness against competing TCP traffic to the potential for congestion collapse. To promote the inclusion of end-to-end congestion control in the design of future protocols using best-effort traffic, we argue that router mechanisms are needed to identify and restrict the bandwidth of selected high-bandwidth best-effort flows in times of congestion. The paper discusses several general approaches for identifying those flows suitable for bandwidth regulation. These approaches are to identify a high-bandwidth flow in times of congestion as unresponsive, “not TCP-friendly”, or simply using disproportionate bandwidth. A flow that is not “TCP-friendly” is one whose long-term arrival rate exceeds that of any conformant TCP in the same circumstances. An unresponsive flow is one failing to reduce its offered load at a router in response to an increased packet drop rate, and a disproportionate-bandwidth flow is one that uses considerably more bandwidth than other flows in a time of congestion
This paper uses simulations to explore the benefits of adding selective acknowledgments (SACK) and selective repeat to TCP. We compare Tahoe and Reno TCP, the two most common reference implementations for TCP, with two modified versions of Reno TCP. The first version is New-Reno TCP, a modified version of TCP without SACK that avoids some of Reno TCP's performance problems when multiple packets are dropped from a window of data. The second version is SACK TCP, a conservative extension of Reno TCP modified to use the SACK option being proposed in the Internet Engineering Task Force (IETF). We describe the congestion control algorithms in our simulated implementation of SACK TCP and show that while selective acknowledgments are not required to solve Reno TCP's performance problems when multiple packets are dropped, the absence of selective acknowledgments does impose limits to TCP's ultimate performance. In particular, we show that without selective acknowledgments, TCP implementations are constrained to either retransmit at most one dropped packet per round-trip time, or to retransmit packets that might have already been successfully delivered. 1
This book gives an introduction to the technology of communications
satellites. Fundamental problems are formulated and basic engineering
solutions are described. Attention is given to multiplexing, modulation,
PCM and delta modulation, multiple access and demand assignment,
time-division and frequency-division multiple access, transmission
errors, use of satellites for interactive computing, packet radio
terminals, burst reservation systems, availability computations, and
tradeoffs in system design.