Q1: What's meaning of PAN, LAN, MAN, WAN and internet



  1. PANs(Personal Area Network) let devices communicate over the range of a person. A little example are wireless mouse, wireless keyboard that based on Bluetooth.
  2. LAN(Local Area Network) is a privately owned network that operates within and nearby a single building like a home, office or factory. When LANs are used by companies, the are called enterprise networks". AP, wireless router, base station are LAN devices.
  3. MAN(Metropolitan Area Network) covers a city.
  4. WAN(Wide Area Network) spans a large geographical area, often a country or continent.
  5. Internetwork(also called internet) is a collection of interconnected networks.

Q2: what's the difference of layer and interface.


a protocol is an agreement between the communicating parties on how communication is to proceed.

A list of the protocols used by a certain system, one protocol per layer, is called a protocol stack.

Between each pair of adjacent layers is an interface.The interface defines which primitive operations and services the lower layer makes available to the upper one.

Q3: what are design issues for the layers


  1. Reliability

    1. error detection
    2. finding a working path through a network
  2. the evolution of the network
  3. resource allocation
  4. security

标签: network