問91
頻出度★★★
WANの説明として, 最も適切なものはどれか。
平成30年度 秋期 ITパスポート試験 問91
テクノロジ系ネットワーク › ネットワーク方式
This question's explanation and your answers so far.
解説
問 91
Incorrectア
“A virtual private network built by using the Internet”describes a VPN (Virtual Private Network). It is a technology that builds a virtual dedicated line over the Internet, which is a public network, by means such as encryption; it is not the definition of a WAN itself.
Incorrectイ
The restriction “a network that connects country to country”is wrong. The essence of a WAN is “a wide-area network that connects geographically distant locations”; whether or not it crosses national borders is not a condition, and a network that connects distant sites within a single country is also a WAN. It is inappropriate in that it states the scope is limited to the international.
- ウ
正解 A WAN (Wide Area Network) is a wide-area network that, by using services such as the network service provided by a telecommunications carrier, connects geographically distant locations such as a head office and a branch office (that is, the LANs at each site to one another). Choice ウ matches this definition exactly. In contrast to a LAN, which connects a small area (within a building or premises), the essence of a WAN is that it does not lay all of the lines itself but connects remote sites via the lines and services of a telecommunications carrier; therefore ウ is the most appropriate.
Incorrectエ
“A brand name given only to devices whose interoperability has been verified among IEEE 802.11 standard-compliant products for wireless LANs”describes Wi-Fi (a brand certified by the Wi-Fi Alliance) and has nothing to do with a WAN.
ここがポイント
- Definition of a WAN (wide-area network): a wide-area network that uses services such as a telecommunications carrier's network service to connect geographically distant sites (LANs to one another), such as a head office and a branch office. Understand it in contrast to a LAN, which connects a building or a small area.
- Distinguishing confusing terms: do not confuse a WAN with a virtual dedicated line over the Internet = VPN (ア), or with the wireless LAN interoperability certification brand = Wi-Fi (エ).
用語