Between devices of two networks within a network shared is where you can create a logical circuit called a virtual circuit which is classified into two categories, permanent and switched.
Data transfer is one mode composing a virtual circuit that is established permanently and this is used in constant transfer of data between devices. The bandwidth use linked with the virtual circuit creation and stoppage is lowered with virtual circuit permanent category, but because of the continuous availability of the virtual circuit, the price goes higher. For service purposes, when placing an order, the service provider configures the virtual circuit permanent category in general.
While on the other hand, when transmission is done, virtual circuits that is created on demand and is stopped, it’s called virtual circuit’s switched category. There are three phases of communication for virtual circuit’s switched category, namely: termination of circuit, establishment of circuit, and transfer of data. The creation of virtual circuit between devices of destination and the source are the things involved in the phases of establishment. The data transmission between the devices over the virtual circuit is what is involved in transferring of data, and the tearing down of virtual circuit between devices of destination and the source is what is involved in the stoppage phase of the circuit. Whenever there is a sporadic transfer of data between devices, you may rely on what the switched virtual circuit can do because it can make the bandwidth higher to use for creating circuit and the phases of stoppage, but with the continuous availability of virtual circuit, the price becomes lower.
On the other hand, for Wide Area Network connectivity, there are techniques that the dialup services offered which are cost-effective. The dial backup and Dial-on-Demand Routing are two implementations of dialup that are widely-known.
When sending data is necessary, a switched circuit is initiated on a call through using a router, a method of Dial-on-Demand. The transmission needed for the traffic of a specific network type is the requirement for call initiation when configuration of the router is done in the setup for Dial-on-Demand. Over the line when the traffic passes, it’s an indication that the connection was made successfully. When for a specific time, the circuit continuously stays idle, a timer specifying the idleness of the router for connection dropping is what indicated on the configuration of the router.
For the configuration of Dial-on-Demand, another way to do it is by dial backup where the circuit switched is used to provide backup service for a different circuit type like switching, either packet or point-to-point. The initiation of the dial backup line goes when on the primary circuit found a failure, and for that reason configuration of the router is a must. Not until the restoration of the primary circuit, the connectivity for Wide Area Network is supported by the dial backup and if this happens, the connection stoppage for the dial backup takes place.
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