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15 Cards in this Set
- Front
- Back
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Computer Network |
A collection of computers and computer resources (printers, file servers) connected in such a way that the computers can communicate with each other and their resources. |
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Role of networks |
Allow hardware to be shared between: 1. software (sharing a printer) 2. people (mail server) Allow software to be shared between: 1. hardware (customer database on a central server) 2. people (email program) Allow people to interface with other people inside and outside of the organization. |
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Big picture of IT |
Hardware, software, and users combine to create computer networks. |
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Local computer |
A computer that the user is using; physically present with that computer.
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Remote computer |
A computer that is accessed over the network (remote desktop, telnet [ssh or secure shell]. |
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Physical level |
Connections or physical media over which communication is possible. |
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Logical level |
Network topology (Bus, Mesh, Star, Ring) |
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Software level |
Protocols and programs that allow the computers to communicate. |
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Physical forms of network connections |
1. UTP (unshielded twisted pair) 2. Fiber optic cable - light pulses 3. Coaxial cable/twisted wire - electomagnetic waves Long distance, radio signals are sent via radio towers, cell phone towers, and satellites in orbit |
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Networks bandwidth |
Transfer rate permissible over the media: 1. bits per second (bps or b/s) 2. millions or billions of bits per second (Mbits/second, Mbps or Gbits, Gbps) - modern bandwidth |
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Broadcast devices |
These devices glue the network together by providing a point the network can connect to devices and other networks 1. Hubs 2. Switches 3. Routers 4. Wireless access point (WAP) - most popular |
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Network hub |
1. Device that connects multiple computers together. 2. A message received by the hub is forwarded to all ports on the hub. 3. A destination address attached to the message states which computer the message is for, but does not prevent other computers from picking up the message. 4. Broadcasts the transmission and sends the data to every device in the network. |
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Network switch |
1. More functional than a hub. 2. Records and recognizes the local network address (MAC or IP addresses) of all the computers connected to the switch. 3. Message is passed only to the computer that matches the destination address. 4. Utilizes network bandwidth efficiently. 5. Broadcasts to all computers, but transmission is sent to a specific computer. 6. More hardware than a hub. |
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Router |
1. Connects multiple networks together. 2. Routes messages to other networks. 3. Contains programmable routing tables and includes at least 1 input that comes from another network. |
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Wireless access point (WAP) |
1. Can be connected to a hub, switch, or router. 2. Sends wireless signal so computers on network can connect without a cable. 3. Radiowaves are used over long distances via radio and cell phone towers that are bounced off satellites in orbit, giving a broad coverage area. |
