ITPEC FE Morning October 2021 Question 30
In the OSI basic reference model, which of the following is a network device that operates at the network layer?
Explanation
Router — it forwards packets between networks by their IP addresses, which is network layer (layer 3) work.
A router reads the destination IP address in each packet, looks it up in its routing table and sends the packet towards the next network, so it joins different networks and chooses the path between them.
Answer (d)
Why not others:
- •(a) Access point — connects wireless devices to a LAN, bridging frames by MAC address at the data link layer
- •(b) Bridge — forwards or filters frames by MAC address within one network, at the data link layer (layer 2)
- •(c) Repeater — only regenerates and amplifies the electrical signal, at the physical layer (layer 1)
Key rule: Match the device to the address it reads: none (repeater, hub) is layer 1, MAC address (bridge, switch) is layer 2, IP address (router) is layer 3, and protocol conversion above that is a gateway.
Networks · AI-written, may contain errors
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