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Networking on the International Space Station. Presentation by Bradley Roach 10/09/2007. Objectives of Discussion.
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Networking on the International Space Station Presentation by Bradley Roach 10/09/2007
Objectives of Discussion • To highlight and discuss the following areas of the Operations Local Area Network (OPS LAN) system used to facilitate communication between laptop computers on the International Space Station. • Network Topology • Networking Protocols • Network Devices • RF Connectivity • Cabled Connectivity
Topology of OPS LAN • OPS LAN uses a Multipoint Ethernet Bus Topology • Multipoint enables the hub to send information to one or more systems based on a specific address. • Uses IEEE 802.3 (Regular Ethernet) • Uses IEEE 802.11(Wireless Ethernet) • The OPS LAN 10BASE2 cable backbone uses RG-58 coax cabling. • Uses BNC connectors and terminators.
Network Protocols Used On OPS LAN • Protocol- Collection of rules and procedures governing communication among the computers and network devices of the network. • NetBEUI (NetBIOS Extended User Interface) • Very fast but non-routable • Self-tuning and self-configuring • Suitable for small networks such as OPS LAN • Uses broadcasts to locate other computers on the network. • TCP/IP (Transmission Control Protocol / Internet Protocol) • Most common network protocol in the world • Routable
Network Devices Used On OPS LAN • The following network devices implemented in OPS LAN will be discussed: • File Server • Various client laptops • RF access points • Mass Storage Device • Printers • Routers
File Server • IBM ThinkPad 760XD • Equipped with SSC (Station Support Computer) server software load. • Uses Microsoft Windows NT Server • File server is operated from the service module of the ISS.
SSC Clients • IBM ThinkPad 760XD • Microsoft Windows 95b • During early missions, these clients communicated on the network via RF cards. • In later missions, the clients will communicate via 802.11 or 802.3
Early Communication System/Orbital Communication Adapter • Early Communication System Laptop is IBM ThinkPad 755C • Attached to a docking station to which an Orbital Communication Adaptor and Video Conferencing adapted are attached. • Primary function is to provide communication and data transfer from space to ground. • Primary printer used on OPS LAN is an Epson Color Stylus 800 which has been modified for low gravity operation
RF Connectivity • Operates in the 2.4ghz frequency band • Throughput via RF PC cards is 12MB/min; • Expected throughput is between 3.5 and 5.5 MB/Min. • To prevent RF interference and unauthorized eavesdropping, Spread Spectrum Technology is used. • With this technology, the radio signal “hops” from frequency to frequency within a specified band(ISM 2.4000 – 2.4825) over a set time. • Both the transmitter and the receiver know what the hopping pattern is, and are then able to decipher the information. • Each hopping pattern is called a channel, and up to fifteen channels are available.
RF Network Adapter/Access Point • RangeLAN2 7400 PC card • This adapter is a type II pc card • Attached to the PC card is an omnidirectional dipole antenna • 7520 RangeLAN2/AP-II MAC layer bridge • Connects to the coax backbone • Relays packet information from coax backbone to Laptops at a rate of 14,800 packets/sec
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