Transcript Networking on the International Space Station

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
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/SOR071/imagenes/prueba.jpg
http://www.spaceref.com/news/viewnews.html?id=213
http://www.shimafukurou.jp/thinkpad/images/760xd/760xd-01.jpg