What is the primary function of a router?

• A. Encrypts data at the application layer
• B. Directs traffic between networks
• C. Provides wireless access
• D. Translates domain names

Answer: (B)

The key idea here is routing traffic between networks. A router looks at the destination IP address on each packet, uses its routing table to decide the next hop, and forwards the packet toward its destination. This is the network layer function that lets devices on separate networks—such as different LANs or a LAN and the internet—communicate with each other. Routers determine the best paths using routing protocols like OSPF, RIP, or BGP, and they adapt as network conditions change. While a router can also perform additional tasks like NAT or firewalling, those are supplementary; the primary role is directing traffic between networks. Encryption at the application layer happens with protocols like TLS, wireless access is provided by an access point or wireless router, and translating domain names is the job of DNS.