Networks and Switching

• The solution to this problem is to construct networks of switches.
• In communication networking, a switch or exchange is a system that has many inputs and outputs and can connect each of its inputs to any desired output.
• Thus, a switch can create a signal path from any input to any output.
• Originally, in the telephone network this switching function would be performed by human operators in the exchange.
• A communication network is created by connecting a large number of switches.
• Notice, that functionally a network is just like one big switch with a very large number of inputs and outputs.
• A user only needs to be connected to a single switch.
• Therefore, only a single cable connects your phone to the rest of the world.

  

Figure 2.37: Diagram for Switch or Exchange.