問68
頻出度★★★
通信方式に関する記述のうち, 適切なものはどれか。
平成27年度 秋期 ITパスポート試験 問68
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 68
Incorrectア
Delivering data dynamically while selecting the route as appropriate is a characteristic of the packet switching method, not the circuit switching method. The circuit switching method establishes a single route to the recipient at the start of communication and keeps monopolizing that same route until the communication ends, so it does not perform dynamic route selection that switches routes midway. The subject is reversed, so this is wrong.
Incorrectイ
The exclusive assertion that packet switching handles only digital signals and circuit switching handles only analog signals is wrong. The circuit switching method can also handle digital signals (for example, digital lines), and the two methods cannot be distinguished by the kind of signal they handle. The essential difference between the two methods is not the type of signal but how the line is used (monopolized or shared).
- ウ
正解 The packet switching method splits data into small units called packets, attaches destination information, and sends them. It does not monopolize the line; instead it can interleave the packets of multiple users onto the same communication line, achieving statistical multiplexing. As a result, the idle time of the line is not wasted and the line can be shared and used efficiently. This is the greatest advantage of packet switching, and the statement in choice ウ correctly describes this property, so it is appropriate.
Incorrectエ
The assertion that packet switching can be used only wirelessly and circuit switching only over wired connections is wrong. Both methods can be used regardless of whether the medium is wired or wireless; the transmission medium (wired/wireless) and the switching method (circuit/packet switching) are independent concepts. There is no basis for pairing them one to one.
ここがポイント
- Key point of packet switching: data is split into packets, and through statistical multiplexing multiple users share the same line and use it efficiently. The circuit switching method monopolizes the route throughout the entire communication.
- The difference between switching methods lies in whether the line is monopolized or shared, not in the type of signal (digital/analog) or the transmission medium (wired/wireless).
用語