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International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / The Consultative Committee for Space Data Systems (CCSDS) developed the CCSDS File Delivery Protocol (CFDP) to provide reliable delivery of files across space links. Space links are typically intermittent, requiring flexibility on the part of CFDP. Some aspects of that flexibility will be highlighted in this paper, which discusses the planned use of CFDP on the Global Precipitation Measurement (GPM) mission. The operational scenario for GPM involves reliable downlink of science data files at a high datarate (approximately 4 megabits per second) over a space link that is not only intermittent, but also one-way most of the time. This paper will describe how that scenario is easily handled by CFDP, despite the fact that reliable delivery requires a feedback loop.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Reliable delivery of data products is often required across space links. For example, a NASA mission will require reliable delivery of images produced by an on-board detector. Many missions have their own (unique) way of accomplishing this, requiring custom software. Many missions also require manual operations (e.g. the telemetry receiver software keeps track of what data is missing, and a person manually inputs the appropriate commands to request retransmissions). The Consultative Committee for Space Data Systems (CCSDS) developed the CCSDS File Delivery Protocol (CFDP) specifically for this situation. CFDP is an international standard communication protocol that provides reliable delivery of data products. It is designed for use across space links. It will work well if run over the widely used CCSDS Telemetry and Telecommand protocols. However, it can be run over any protocol, and will work well as long as the underlying protocol delivers a reasonable portion of the data. The CFDP receiver will autonomously determine what data is missing, and request retransmissions as needed. The CFDP sender will autonomously perform the requested transmissions. When the entire data product is delivered, the CFDP receiver will let the CFDP sender know that the transaction has completed successfully. The result is that custom software becomes standard, and manual operations become autonomous. This paper will consider various ways of achieving reliable file delivery, explain why CFDP is the optimal choice for use over space links, explain how the core protocol works, and give some guidance on how to best utilize CFDP within various mission scenarios. It will also touch on additional features of CFDP, as well as other uses for CFDP (e.g. the loading of on-board memory and tables).

Överföring eller mottagande av datorfiler är en syssla som de flesta av oss ägnar ossåt regelbundet i ett eller annat sammanhang, oavsett om det sker privat eller om detär arbetsrelaterat. File Transfer Protocol (FTP) är ett protokoll för just detta ändamålsom lanserades under tiden då persondatorer hade blivit allt vanligare i hemmetoch på arbetsplatsen. Sedan dess har flera andra protokoll introducerats och i dagslägetfinns det flertalet valmöjligheter tillgängliga, alla med sina unika såväl som gemensammaegenskaper. Simple Mail Transfer Protocol (SMTP) kompletterad medMIME-standarden är ett populärt alternativ till de renodlade filöverföringsprotokollenpå grund av användarnas bekantskap och tidigare erfarenheter med e-posttjänster.Att skicka och ta emot filer via e-post innebär dock vissa begränsningar samt att vissasäkerhetsaspekter måste tas i beaktande, i synnerhet för företagsanvändare som dagin och dag ut måste hantera känslig data. I denna uppsats har tre olika filöverföringsprotokoll(SFTP, SMTP och HTTP) utvärderats ur ett användarvänlighetsperspektivsåväl som ett säkerhetsperspektiv. Resultatet indikerar att HTTP(S) tillsammans meduttökningen WebDAV kan anses vara ett lämpligt alternativ för organisationer somsamtidigt är enkelt att använda. De övriga protokollen, SMTP och SFTP, har ocksåsina användningsområden där SFTP verkar vara mer tilltalande för avanceradeanvändare och där SMTP förblir ett gångbart alternativ för privat bruk av mindreavancerade användare under vissa förutsättningar. / Transferring and receiving computer files are something most of us do on a regularbasis whether it is for private purposes or if it is work related. FTP is a protocolused for this very purpose which was launched during a time when personal computerswere growing increasingly popular in both home and workplace environments.Since then, more protocols have been introduced and today there are a number ofoptions available bringing new and common features alike to the market. The SMTPprotocol, extended with the MIME standard, is currently a widely used alternative tothe pure file transfer protocols due to the user familiarity and past experiences withthese mail services. Sending and receiving files through e-mail does however implysome limitations together with the fact that some security aspects need to be takeninto consideration, particularly for company users handling sensitive data. In thisthesis, three different file transfer protocols (SMTP, SFTP and HTTP) have all beenevaluated in account of their user friendliness as well as their security features. Theresults indicate that HTTP(S) combined with the WebDAV extension can be considereda viable alternative for organizations due to its user friendliness and security.The remaining protocols, SMTP and SFTP, also have their uses where SFTP wouldseem to be an appealing option for advanced users and where SMTP remains a passablealternative for private usage by regular users under the right conditions.

Due to the rapid development of the Internet and the fast expansion of the bandwidth, the requirement of the real-time service for the Internet is necessary. In this way, the problem of the real-time service for the Internet becomes an important issue. Most of the applications still use TCP as the protocol, but due to the reliable property of TCP, TCP can¡¦t fit the requirement of the real-time transfer. So, we need to implement a protocol which we can use on the real-time transfer service. According to the requirement, we find an open source application layer protocol ¡V UDT (UDP-based Data Transfer). We can implement the application of real-time transfer by using the partial reliable messaging property of the protocol. In addition, user can adjust the parameters or settings of the protocol to make their application get into better performance by using the composable property of the protocol. In our research, we¡¦ll compare with RTP (Real-time Transport Protocol) and UDT, and also explain the reason why we don¡¦t choose RTP in our research. The assumption environment of our research is financial real-time service, and the protocol of such applications is TCP. In this way, we¡¦ll analyze and compare the result of the tests between TCP and UDT. We¡¦ll also adjust the parameters of the protocol to test the performance of the UDT under the environment of the real-time transfer, such as data lose rate, etc.. These results can supply the reference for the users when using UDT as their protocol to implement their real-time applications.

Thesis (M.S. in Computer Science)--Naval Postgraduate School, March 2004. / Thesis advisor(s): Wen Su, John Gibson. Includes bibliographical references (p. 189). Also available online.

Thesis (M.Sc.(Computer Science))--University of Pretoria, 2000. / Summaries in Afrikaans and English.

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This master thesis is mainly focused on the backup systems and describes each individual backup techniques in detail. Next main point of this thesis, is explaining functionality of IPv4 and FTP, which are closely related to the topic. Outcome is a backup application written in Java language, which is capable of backup files on FTP server or on local/ network storage area. Backup application also allows settings for automatic backup and restoring files from the storage area. Finally there was made a measurment, where were point out advantages and disadvantages of transfer mediums and where was practically shown a logic of creating the backup system. Goal was a creation of multiplatform backup application.

International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / Today it is not uncommon to have large contractor teams involved in the design and deployment of even small satellite systems. The larger (and more geographically remote) the team members, the more difficult it becomes to efficiently manage the disbursement of telemetry data for evaluation and analysis. Further complications are introduced if some of the telemetry data is sensitive. An application is described which can facilitate telemetry data sharing utilizing the National Information Infrastructure (Internet).