An operational open-end file transfer protocol for mobile satellite communications

This paper describes an operational open-end file transfer protocol which includes the connecting procedure, data transfer, and relinquishment procedure for mobile satellite communications. The protocol makes use of the frame level and packet level formats of the X.25 standard for the data link layer and network layer, respectively. The structure of a testbed for experimental simulation of this protocol over a mobile fading channel is also introduced

Non-repudiation secure file transfer protocol (NRSFTP)

Non Repudiation Secure File Transfer Protocol (NRSFTP) is designed to resolve three main concerns for today\u27s electronic file transfer methodology. The three main concerns are Non-Repudiation, Secure, and Non-Real Time file transfer. Non-repudiation is to assure the receiver that the sender of the document is not an imposter. Secure document transfer is to assure the sender that only the intended receiver will be able to read the document. Non-real-time file transfer is to provide convenient and low cost transportability of the encrypted data from one party to another. With the above three concerns addressed, the NRSFTP protocol can be widely accepted by the general public as the method to securely transfer a file

File Fragmentation over an Unreliable Channel

It has been recently discovered that heavy-tailed file completion time can result from protocol interaction even when file sizes are light-tailed. A key to this phenomenon is the RESTART feature where if a file transfer is interrupted before it is completed, the transfer needs to restart from the beginning. In this paper, we show that independent or bounded fragmentation guarantees light-tailed file completion time as long as the file size is light-tailed, i.e., in this case, heavy-tailed file completion time can only originate from heavy-tailed file sizes. If the file size is heavy-tailed, then the file completion time is necessarily heavy-tailed. For this case, we show that when the file size distribution is regularly varying, then under independent or bounded fragmentation, the completion time tail distribution function is asymptotically upper bounded by that of the original file size stretched by a constant factor. We then prove that if the failure distribution has non-decreasing failure rate, the expected completion time is minimized by dividing the file into equal sized fragments; this optimal fragment size is unique but depends on the file size. We also present a simple blind fragmentation policy where the fragment sizes are constant and independent of the file size and prove that it is asymptotically optimal. Finally, we bound the error in expected completion time due to error in modeling of the failure process

A PACS alternative for transmitting DICOM images in a high latency environment

Picture Archiving and Communication System(PACS) is responsible for storing Digital Imaging and Communication in Medicine (DICOM) images fromradiology modalities into its database, images takes a lot of time to transfer to remote location through WAN due to large file size and slow transfer protocol. A PACS alternative system has been developed which performs basic functions of a generic PACS. Images directly from modalities are large in size by default transfer syntax of these images is Endian Explicit syntax. Changing this transfer syntax to lossless JPEG 2000 decreases the file size and because of lossless compression quality of image is still same as original image. These compressed images are then copied into Network Attached Storage working as PACS alternative. A series of test conducted in lab with multiple transfer protocol on Network Attached Storage (NAS) to find out which transfer protocol is faster under moderate speed and high latency network