問78
頻出度★★★
ネットワークを構成する機器であるルータがもつルーティング機能の説明として, 適切なものはどれか。
平成29年度 秋期 ITパスポート試験 問78
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 78
Incorrectア
Centrally managing the settings and status of company-issued mobile devices is a description of MDM (Mobile Device Management), not the routing function of a router.
- イ
正解 A router operates at the network layer of the OSI reference model and is a device that interconnects different networks (subnets). The routing function refers to consulting the routing table, choosing the optimal route to deliver a packet to its destination IP address, and relaying the packet to the next device. Choice “イ” describes this operation exactly, with nothing omitted or added, so it is correct.
Incorrectウ
Connecting optical fiber and copper cable and physically converting the signals between them is the role of a media converter; it is a physical-layer conversion and has nothing to do with route selection.
Incorrectエ
Managing the mapping between host names and IP addresses and responding to queries is the function of a DNS server, which is a different thing from a router's routing.
ここがポイント
- Routing is a network-layer function that interconnects different networks and, based on the routing table, selects the optimal route to the destination and relays packets.
- Distinguishing it from similar devices/functions: MDM (centralized device management), media converter (physical-layer signal conversion), and DNS server (name resolution between host names and IP addresses) are all different from routing.
用語