(Chapter 6) Data Communications: Delivering Information
What three things must be present for communication to occur?
* Transmission media
* Data transmission
* Bandwidth: Amount of data that can be transferred from one point to another in a certain time period, usually one second expressed as bits per sec.
* Attenuation: Loss of power in a signal as it travels from the sending device to the receiving device
What is a protocol and why is it important in electronic communications?
* Protocol: Rules that govern data communication, including error detection, message length, and transmission speed
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* More responsive to users
* Lack of coordination
* High costs
* Duplication of efforts
* Distributed: Centralized control and decentralized operations. Processing power is distributed among several locations.
* Accessing unused processing power is possible
* Computer power can be added or removed
* Distance and location aren’t limiting
* More compatible with organizational growth
* Fault tolerance
* Resources can be shared to reduce costs
* Reliability is improved
* More responsive to user needs
* Dependence on communication technology
* Incompatibility between equipment
* More challenging network management
If provided an example, be able to determine if the network is an example of a WAN, MAN, or LAN.
* Local Area Network (LAN): Connects workstations and peripheral devices that are in close proximity.
* Used to share resources, such as peripherals, files, and software. They are also used to integrate services, such as e-mail and file sharing.
* Data transfer speed varies from 100 Mbps to 10 Gbps.
* Ethernet is the main type of LAN today
* Wide Area Network (WAN): Can span several cities, states, or even countries, and is usually owned by several different parties.
* Can be useful for a company headquarter in Washington D.C., with 30 branch offices in 30 states.
* Use many different communication media
* Major carriers lease lines to companies
* Data transfer speed varies from 28.8 Kbps to 155 Mbps.
* Metropolitan Area Network (MAN): Designed to handle data communication for multiple organizations in a city and sometimes nearby cities as well.
* Data transfer speed varies from 34 Mbps to 155 Mbps.
Distinguish the difference between a PAN and a BAN.
* PANs – Personal Area Networks,
* WPANs – Wireless Personal Area Networks
* For connecting devices in a person’s workspace
* Bluetooth, ZigBee, WiFi
* BANs – Body Area Networks
* WBANs or Body Sensor Network (BSN)
* Wearable or implanted devices
* Security, power, and bandwidth are major issues
* Protocols still in early stage of development
If provided an example, be able to distinguish if the network topology is a star, ring, bus, hierarchy, or mesh network.
* Star Topology: Central computer (host computer, often a server) and a series of nodes (typically, workstations or peripheral devices.)
* The host computer supplies the main processing power.
* Cable layouts are easy to modify
* Centralized control makes detecting problems easier
* Nodes can be added to the network easily
* Better for handling heavy, short bursts of traffic
* Single point of potential failure
* Increased cost due to many cables
* Ring Topology: No host computer is required because each computer manages its own...