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Flashcards in 1 - Introduction Deck (15):
1

What are data communications?

The exchange of data between two devices via some form of transmission medium.

2

What are the 5 components of data communication?

1. Protocol (rules)
2. Sender
3. Message/Medium
4. Receiver
5. Protocol (rules)

3

What is simplex delivery?

Only one direction of data, mainframe to data.

4

What is half-duplex delivery? What's an example?

Two direction transmission of data, only one at a time. Walkie-talkies.

5

What is full-duplex delivery?

Two direction transmission of data, all the time

6

What is a network?

A set of devices (or nodes) connected by communication links.

7

What is the formula for number of links in a mesh topology?

N*(N-1)/2, N is number of stations.

8

What is the minimum number of links for a star, bus, and ring topology?

N, the same as the number of stations.

9

What are some advantages and disadvantages to mesh topology? What is an example?

Advantages:
- robust
- private
- easy to find faults
Disadvantages:
- Hardware (cabling, I/O ports)

Example: backbone connecting

10

What are some advantages and disadvantages to star topology? What is an example?

Adv:
- less expensive than mesh
- private
disadv:
- if hub goes down everything does

Example: LAN

11

What are some advantages and disadvantages to bus topology? What is an example?

Adv:
- easy to implement
disadv:
- difficult reconnection and fault isolation
- signal reflection causes quality degradation, hard to add new nodes

Example: LAN

12

What are some advantages and disadvantages to ring topology? What is an example?

Adv:
- easy to implement, reconfigure
- fault isolation
disadv:
- unidirectional traffic, one break disables the entire network

Example: LAN

13

What are some characteristics of LAN networks?

- Sharing in local area, a few km
- One type of transmission medium for a given LAN
- 4 Mbps -> more than 1G Mbps (modern day)

14

What are some characteristics of WAN networks?

- Long distance transmission
- Can be very complex or as simple as dialup (point to point)

15

What is circuit switching vs. packet switching?

Circuit: set up between two terminals for duration of conversation.
Packet: packet can follow different paths to destination, many connections, internet