cisco ccna devnet

cisco ccna devnet.Chapter 24 Introduction to WAN 643provide bandwidth guarantees.Asynchronous serial connections are the cheapest WAN service, but they are also the slowest and most unreliable. For example, whenever you establish a connection using an analog modem, there is no guarantee of connection speed. In the US, these connections can reach speeds of up to 53kbit/s, but can be as low as 300bit/s, depending on the quality of the connection. In the United States, the Federal Communications Commission (FCC) specifies a maximum analog data rate of 53 kbit/s, but other countries may support higher data rates.The main problem with circuit-switched connections is that if a long-distance connection is required, the cost will be high - the cost per minute varies with the destination of the connection: the more data to be sent, the more time it will take, and therefore the more you will have to pay. As a result, asynchronous circuit-switched connections are often used in home offices and for low-speed backup connections, and as temporary low-speed connections for additional bandwidth in the event of congestion or failure on the main link.When using leased lines, after the circuit is installed and the DTE is configured, the line will always be available unless the carrier's network, DTE or DCE equipment fails. This is different from a circuit-switched connection. A circuit-switched connection is temporary: a number is dialed to a remote DTE device, a connection is established, and data transfer begins; when the data transfer is complete, the phone connection is then disconnected.To use a circuit-switched analog connection, the following equipment is required..DTE: router with asynchronous serial interface..DCE: modem.To use a circuit-switched digital connection, the following equipment is required..DTE: Router with ISDN interface.