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 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 10 BASE 2 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. Net. BEUI (Net. BIOS 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 Think. Pad 760 XD 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 Think. Pad 760 XD Microsoft Windows 95 b 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 Think. Pad 755 C 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. 4 ghz frequency band Throughput via RF PC cards is 12 MB/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 Range. LAN 2 7400 PC card This adapter is a type II pc card Attached to the PC card is an omnidirectional dipole antenna 7520 Range. LAN 2/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
http: //www. spaceref. com/iss/computer/iss. ops. lan. icd. pdf http: //www. spacescan. org/images/international-space-station-ctrl_65. jpg http: //www. inetdaemon. com/tutorials/lan/topology. shtml http: //newsroom. cisco. com/ts_images/cisco_10720_Internet_Router_high_res. jpg http: //www. elmundo. es/suordenador/SORnumeros/97/SOR 071/imagenes/prueba. jpg http: //www. spaceref. com/news/viewnews. html? id=213 http: //www. shimafukurou. jp/thinkpad/images/760 xd-01. jpg
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