Comtech EF Data VIPERSAT File Streamer v1.2.x - Manual (Page 13)

Chapter 1 - General 1-3
Product Description
Product Description
Introduction
Vipersat File Streamer (VFS) is a software application that allows rapid file
transfers over the Comtech EF Data Vipersat network between host PCs that are
running the VFS application. VFS runs on a Microsoft Windows-based PC/
workstation and, together with the Vipersat Management System (VMS),
utilizes the bandwidth-on-demand capabilities of the system for applications
such as file transfers.
VFS, in conjunction with Vipersat-enabled IP modems and the VMS, can
stream large files from one workstation to another workstation over the satellite
network. VFS overcomes the limitations of TCP/IP over satellite links by imple-
menting an efficient and reliable datagram protocol, while at the same time
having the ability to request dynamic SCPC (dSCPC) satellite bandwidth.
Simplicity of Operation
Through its graphical user interface, VFS simplifies the file transfer process by
allowing the operator to select which files or folders are to be transferred and
where they are to be stored. Files or folders can be dragged from the desktop or
Windows Explorer™ and dropped into the VFS window to create a new transfer
session. Transfers can be scheduled on a periodic basis or performed immedi-
ately. Scheduled transfers during non-peak hours aid in avoiding network
congestion.
Overview
Designed to transfer files across the Vipersat network over satellite, VFS uses
UDP as a transport layer protocol together with the proprietary Streamload
protocol rather than using TCP, a common standard for computer communica-
tions. The advantages that TCP/IP provides for typical internet communications
can become limitations when passing traffic over a satellite network, where
inherent delays can be mistaken for congestion or low bandwidth, resulting in
compromised transmission rates. Instead of constantly monitoring for acknowl-
edgements and retransmission of bad or lost data, the Streamload protocol
streams all data packets and performs any necessary retransmission only at the
end of the session.
With the addition of VFS into the Vipersat Network solution, channel utilization
efficiencies improve dramatically over standard FTP file transfers.
VFS is a peer-to-peer application where each host in the network can directly
communicate with any other host. With VFS, there is no centrally located server
required to manage file transfers in the network. VFS authorization is controlled