Basic question about network

1.What is primary purpose of a LAN ?
- The primary purpose of LAN is to allow resource sharing. The resources may be devices, application, or information. Examples of shared resources are files, database, email, modem, printer.
2.What is protocol ?
-  A protocol is an agreed-upon set of rules. In data communications, the rules usually gorvern a procedure or a format.
3. What is the purpose of a MAC protocol?
- A Media Access Control protocol defines how a give LAN medium is shared, how LAN devices connected to the medium are indentified, and how frames transmiited onto the medium are formatted.
4. What is a frame ?
A frame is a digital "envelope" that provides the information necessary for the delivery of data
 across a data link. Typical components of a frame are identifiers (addresses) of the source and
 destination devices on the data link, an indicator of the type of data enclosed in the frame, and
error-checking information.
5:    What feature is common to all frame types?

 A:    A feature common to all frame types is a format for identifying devices on the data link.

 6:    What is a MAC address or MAC identifier?

 A:    A Media Access Control address or identifier is a means by which individual devices connected to
       a data link are uniquely identified for the purpose of delivering data.

 7:    Why is a MAC address not a true address?

 A:    An address specifies a location. A MAC address is not a true address because it is permanently
       associated with the interface of a specific device and moves whenever the device moves. A MAC
       identifies the device, not the location of the device.

 8:    What are the three sources of signal degradation on a data link?

 A:    The three sources of signal degradation on a data link are attenuation, interference, and distortion.
       Attenuation is a function of the resistance of the medium. Interference is a function of noise
       entering the medium. Distortion is a function of the reactive characteristics of the medium, which
       react differently to different frequency components of the signal.

 9:    What is the purpose of a repeater?

 A:    A repeater is a device that extends the useful range of a physical medium by reading a degraded
       signal and producing a "clean" copy of the signal.