7.1 COMPUTER COMMUNICATIONS CATEGORIES
Basic Categories
Interface to Sensors and Actuators
- Uses readings from sensors to control devices in the environment
- very simple protocols, but often requires specialized hardware and software.
- uses machine to machine connection for direct communication
- can appear to be like a local area network
- low speeds (eg. 300 baud, 1.2, 2.4 9.2 Kbaud)
Local Area Computer Networks
- measured in distances from meters to kilometers
- speed measured in Megabits/sec
- medium includes, wire, fibre-optics, radio frequency
- commonly available in all forms
Wide Area Computer Networks
- from city wide, to global
- speed measured in Kilobytes/second
- medium includes, wire, fibre optics, satellite, microwave
- access is costly (some mix of initial and variable costs), and geared to large corporations, or special applications.
Classification of Interconnected processors (by Physical Size)
Table 1:
Inter-processor Distance
|
Processors Located in Same
|
Example
|
0.1 m
|
Circuit Board
|
Data flow machine
|
1 m
|
System
|
Multi-
processor
|
10 m
|
Room
|
Local
network
|
100 m
|
Building
|
1 km
|
Campus
|
10 km
|
City
|
Long haul network
|
100 km
|
Country
|
1000 km
|
Continent
|
Inter-
connection of long haul networks
|
10000 km
|
Planet
|
