Term
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Definition
| A network that traverses some distance and connects LANs |
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Term
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Definition
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Term
| What does an NSP provide? |
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Definition
| publicly available communications networks by long-distance communications carriers |
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Term
| What is a dedicated line? |
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Definition
| A continuously available communications channel |
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Term
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Definition
| An individual geographic location connected by a WAN |
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Term
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Definition
| A connection between WAN sites |
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Term
| What are the five main WAN topologies? |
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Definition
| Bus, Ring, Star, Mesh, and Tiered |
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Term
| Describe a WAN Bus Topology |
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Definition
| each site depends on every other site. - does not scale well - one down connection can bring down the entire WAN |
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Term
| Describe a WAN Ring topology |
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Definition
| each site is connected to two other sites - uses two parallel paths - WAN won't go down if one connection goes down - expanding is difficult and costs more than a bus topology |
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Term
| Describe a WAN Star topology |
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Definition
| a single site is the central location - different routes to different sites - one down connection only brings down one site |
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Term
| Describe a WAN Mesh topology |
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Definition
| sites are connected to many other sites - one down connection won't bring down the WAN |
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Term
| Describe a full mesh WAN topology |
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Definition
| each site is connected to each other site |
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Term
| Describe a partial mesh WAN topology |
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Definition
| critical sites are interconnected but each point is not connected directly with every other point |
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Term
| Describe a WAN Tiered topology |
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Definition
| points are interconnected at different levels, with interconnection points being organized into layers to form groupings |
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Term
| What does PSTN stand for? |
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Definition
| Public Switched Telephone Network |
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Term
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Definition
| Plain Old Telephone Service |
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Term
| What does modem stand for? |
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Definition
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Term
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Definition
| converts digital signals to analog tones that are sent over telephone wires. Also, converts analog tones back to digital pulses that the computer can understand. Analog tones only go to the nearest central office which converts the tones to digital signal for high speed transmision to the destination central office which converts the digital signal back to analog tones for delivery at the destination modem. |
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Term
| What is the local loop (last mile) |
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Definition
| The portion of the PSTN that connects your house to the nearest central office |
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Term
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Definition
| analog - 56 Kbps - mainframe to remote terminals - packet switching - not common in North America - shown as a cloud |
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Term
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Definition
| digital - packet switching - 1.544 Mbps - more efficient due to packet switching - shared lines at mercy of others - uses CSU/DSU - pay only for bandwidth required - cheaper than ATM |
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Term
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Definition
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Term
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Definition
| any number of different paths - not dedicated lines - contract has endpoints and bandwidth |
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Term
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Definition
| Committed Information Rate |
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Term
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Definition
| Minimum amount of bandwidth guaranteed by service provider |
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Term
| What does ISDN stand for? |
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Definition
| Integrated Services Digital Network |
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Term
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Definition
| International standard for transmitting digital data over PSTN -- Specifies protocols at Physical, Data Link, Transport layers -- Handle signaling, framing, connection setup and termination, routing, flow control, error detection and correction -- Dial-up or dedicated connections -- Carries voice calls and data simultaneously on one line |
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