問58
頻出度★★★
ネットワークインタフェースカードの役割として, 適切なものはどれか。
平成23年度 秋期 ITパスポート試験 問58
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 58
Incorrectア
This describes a terminal adapter (TA). It is a device that performs signal conversion so that communication equipment such as analog telephones and PCs, which cannot connect to ISDN as is, can be connected to ISDN; its target is not a LAN but an ISDN line on the WAN side. A NIC does not perform signal conversion for ISDN.
- イ
正解 The correct answer is イ. A network interface card (NIC, also called a LAN card or LAN adapter) is the hardware that connects devices such as PCs and printers to a LAN over a LAN cable or wireless LAN so that they can communicate. Every NIC has its own globally unique MAC address. It converts data inside the device into electrical signals or radio waves that can travel over the LAN transmission medium and sends them out, and on the receiving side it performs the reverse conversion. In other words, the role of a NIC is to provide the entry point (interface) that attaches a device to a LAN, and イ states exactly that, so it is appropriate. In today's PCs and printers the NIC is usually built into the board, but its role is unchanged.
Incorrectウ
This describes a PLC (power line communication) adapter. It superimposes communication signals onto indoor power lines to send them, and on the receiving side separates the electric power from the communication signals, thereby building a LAN. Building a LAN is indeed related to what a NIC does, but superimposing signals onto power lines and separating them again is a function unique to a PLC adapter, not the role of a NIC.
Incorrectエ
This describes DNS (Domain Name System). It is the name resolution mechanism that converts a host name such as www.example.jp into an IP address, and it is a service handled by software or a server. A NIC is hardware and does not perform name resolution.
ここがポイント
- NIC (network interface card, LAN card) = the hardware used to connect devices such as PCs and printers to a LAN. It has its own unique MAC address and handles sending and receiving data on the LAN.
- Telling similar terms apart: a terminal adapter (TA) does signal conversion for ISDN connections, a PLC adapter superimposes and separates communication signals on power lines, and DNS resolves a host name into an IP address. Sort them out by what they connect to (a LAN, ISDN, or power lines) and by whether they are hardware or a service.
用語