問96
頻出度★★★
ネットワークにおける輻輳に関する記述として，適切なものはどれか。
平成29年度 春期 ITパスポート試験 問96
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 96
Incorrectア
A momentary interruption of the line connection with packet loss describes a momentary disconnection or line fault; its cause differs from congestion, which arises from concentrated traffic. The difference is that in congestion the line itself is alive, yet communication becomes difficult because of the crowding.
Incorrectイ
Routing information being rewritten so that communication data reaches the wrong destination describes a routing error or tampering (such as unauthorized access or DNS/route spoofing); it has nothing to do with congestion, which means crowding.
- ウ
正解 Congestion refers to a state in which communication requests or packets surge in a short time and exceed the capacity that the network can handle (bandwidth or the processing power of the equipment), so that connections become difficult to establish, or delays and packet loss occur. Picture cars concentrating at an intersection and causing a traffic jam; the cause lies in the concentration of traffic itself. Therefore, choice ウ, which states that communication surges, exceeds the network's capacity, and connections become difficult, is correct.
Incorrectエ
Sending a single packet to an unspecified large number of nodes at once describes broadcast (one-to-all transmission). It is a kind of transmission method, not congestion, which denotes a crowded state of the network.
ここがポイント
- Congestion = a crowded state where a surge in traffic exceeds the network's capacity and connections become difficult; it is equivalent to a traffic jam on a road.
- Distinguishing it from similar terms: momentary disconnection (the line briefly cuts off), route spoofing/tampering (data reaches the wrong destination), and broadcast (simultaneous transmission to many nodes) are all concepts separate from congestion.
用語