Networks, Packets & Delay
Explain how a message crosses a network and calculate simple transmission delay.
From devices to the Internet
A computer network connects hosts through links and forwarding devices. A host sends data; a switch forwards frames inside a local network; a router forwards packets between networks. The Internet is a network of independently operated networks that exchange IP packets.
A web page request crosses your Wi-Fi network, an access router, provider networks and the destination network. Each hop forwards the packet toward its destination; the entire page is rarely one packet.
Packet switching and delay
A sender splits a message into packets that can share links with other traffic. Store-and-forward routers normally receive a packet before forwarding it. Transmission delay is packet bits ÷ link bits per second; propagation delay is distance ÷ signal speed. Queuing and processing add further delay.
Bandwidth measures capacity, while latency measures time. A faster link may transmit a packet sooner without making a distant signal propagate faster.
Check your understanding
Which delay depends directly on packet size and link rate?