Cisco CCNA mock exam questions sample test – Question 84

.Which WAN switching technology is used by Asynchronous Transfer Mode (ATM)?

A. cell-switching
B. virtual switching
C. circuit-switching
D. packet switching

Correct Answer: A

Explanation:
Cell switching is used by Asynchronous Transfer Mode (ATM). ATM is an International Telecommunication Union-Telecommunications (ITU-T) standard for transmission of data,
voice, or video traffic using a fixed size frame of 53 bytes, known as cells. Out of these 53 bytes, the initial five bytes are header information and the remaining 48 bytes are the
payload.
The term virtual switching is incorrect because it is not a valid WAN switching technology.
Circuit switching dynamically establishes a virtual connection between a source and destination. The virtual connection cannot be used by other callers unless the circuit is released.
Circuit switching is the most common technique used with the Public Switched Telephone Network (PSTN) to make phone calls. The dedicated circuit is temporarily established for the
duration of the call between caller and receiver. Once the caller or receiver hangs up the phone, the circuit is released and is made available to other users.
Packet switching is also used for data transfer but not in an ATM network. With packet switching, the data is broken into labeled packets and is transmitted using packet-switching
networks. The Internet and LAN communications use packet switching.
Objective:
WAN Technologies
Sub-Objective:
Describe WAN access connectivity options
References:
Cisco > Internetworking Technology Handbook > Asynchronous Transfer Mode (ATM) Switching