SatERN: a PEP-less solution for satellite communications

In networks with very large delay like satellite IPbased networks, standard TCP is unable to correctly grab the available resources. To overcome this problem, Performance Enhancing Proxies (PEPs), which break the end-to-end connection and simulate a receiver close enough to the sender, can be placed before the links with large delay. Although splitting PEPs does not modify the transport protocol at the end nodes, they prevent the use of security protocols such as IPsec. In this paper, we propose solutions to replace the use of PEPs named SatERN. This proposal, based on Explicit Rate Notification (ERN) protocols over IP, does not split connections and is compliant with IP-in-IP tunneling solutions. Finally, we show that the SatERN solution achieves high satellite link utilization and fairness of the satellite traffic

Transport layer protocols and architectures for satellite networks

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-to-long-term perspective. Copyright (c) 2006 John Wiley & Sons, Ltd

Small satellites and CubeSats: survey of structures, architectures, and protocols

The space environment is still challenging but is becoming more and more attractive for an increasing number of entities. In the second half of the 20th century, a huge amount of funds was required to build satellites and gain access to space. Nowadays, it is no longer so. The advancement of technologies allows producing very small hardware components able to survive the strict conditions of the outer space. Consequently, small satellites can be designed for a wide set of missions keeping low design times, production costs, and deployment costs. One widely used type of small satellite is the CubeSat, whose different aspects are surveyed in the following: mission goals, hardware subsystems and components, possible network topologies, channel models, and suitable communication protocols. We also show some future challenges related to the employment of CubeSat networks

ACTS 118x: High Speed TCP Interoperability Testing

With the recent explosion of the Internet and the enormous business opportunities available to communication system providers, great interest has developed in improving the efficiency of data transfer over satellite links using the Transmission Control Protocol (TCP) of the Internet Protocol (IP) suite. The NASA's ACTS experiments program initiated a series of TCP experiments to demonstrate scalability of TCP/IP and determine to what extent the protocol can be optimized over a 622 Mbps satellite link. Through partnerships with the government technology oriented labs, computer, telecommunication, and satellite industries NASA Glenn was able to: (1) promote the development of interoperable, high-performance TCP/IP implementations across multiple computing / operating platforms; (2) work with the satellite industry to answer outstanding questions regarding the use of standard protocols (TCP/IP and ATM) for the delivery of advanced data services, and for use in spacecraft architectures; and (3) conduct a series of TCP/IP interoperability tests over OC12 ATM over a satellite network in a multi-vendor environment using ACTS. The experiments' various network configurations and the results are presented

Secure and Reliable Deep Space Networks

Satellite systems have the advantage of global coverage and inherent broadcast capability and offer a solution for providing broadband access to end users. The main thrust of space communications to-date has been to provide reliable communications between ground mission control and a single spacecraft. Little work has been reported on developing a secure as well as a reliable mode of communications in a deep space satellite network. Our main objective is to develop an algorithm that can increase the reliability (such as in terms of minimum energy consumption) and security in the communications path while minimizing overheads. We realize this by assigning costs to every node and links in the path and then optimally selecting a path with the lowest cost that is also secure. We develop an algorithm to efficiently compute a secure and reliable communications path at minimum cost. The proposed approach is compared to a shortest path approach. Simulation results indicate that although the proposed approach yields slightly longer paths, it provides a more efficient approach in terms of energy distribution as well as secure paths.Computer Science Departmen

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

End-to-End Resilience Mechanisms for Network Transport Protocols

The universal reliance on and hence the need for resilience in network communications has been well established. Current transport protocols are designed to provide fixed mechanisms for error remediation (if any), using techniques such as ARQ, and offer little or no adaptability to underlying network conditions, or to different sets of application requirements. The ubiquitous TCP transport protocol makes too many assumptions about underlying layers to provide resilient end-to-end service in all network scenarios, especially those which include significant heterogeneity. Additionally the properties of reliability, performability, availability, dependability, and survivability are not explicitly addressed in the design, so there is no support for resilience. This dissertation presents considerations which must be taken in designing new resilience mechanisms for future transport protocols to meet service requirements in the face of various attacks and challenges. The primary mechanisms addressed include diverse end-to-end paths, and multi-mode operation for changing network conditions

SATELLITE BASED DATA COMMUNICATION: A SURVEY

ABSTRACT Satellite communication is well known in providing best services where broadcasting is essential, where terrain is hostile and very sparsely populated. It also has niche where rapid deployment is very critical and important. In Global Network Infrastructure satellite is considered as an inseparable component of the communication infrastructure. A variety of research work has been explored and published for satellite based data communication & networking. It is utmost important to conduct a survey on different aspects and research issues of satellite based communication with a focus on the latest development. In this paper, we summarize, compare & comments on the approaches proposed for the satellite based data communication with keeping in view the parameters like Quality of service, Interplanetary Internet, Mobility management, explicit load balancing and packet reordering issue

Satellite-based internet: A tutorial

In a satellite-based Internet system, satellites are used to interconnect heterogeneous network segments and to provide ubiquitous direct Internet access to homes and businesses. This article presents satellite-based Internet architectures and discusses multiple access control, routing, satellite transport, and integrating satellite networks into the global Internet.published_or_final_versio