What is an intermediary device and what are its functions?
A device that interconnects end devices and manages traffic as it flows — switches, routers, wireless access points, firewalls.
End devices (hosts) only create or consume data; intermediary devices are what actually move it between them. They sit in the path of every message and make moment-to-moment decisions about where traffic goes next, which is why a network is far more than just cable. Each function below exists to keep that traffic flowing correctly even as conditions change:
* Intermediary devices sit in the path between hosts, regenerating signals, tracking pathways, and rerouting around failures. *
- Regenerate and retransmit data signals — signals weaken over distance, so the device cleans and rebuilds them so they reach the far end intact.
- Maintain information about network pathways — it remembers which routes lead where, so it can forward each message toward its destination instead of guessing.
- Notify other devices of errors and communication failures — so problems are detected and reacted to rather than silently losing data.
- Direct data along alternate paths when there is a link failure — if one route breaks, traffic is steered around the failure, which is the basis of fault tolerance.
Examples: Switches, routers, wireless access points, firewalls, multilayer switches
Go deeper:
Key Players (Practical Networking) — deepest source on switches vs. routers (intra- vs. inter-network forwarding, MAC/routing tables) — the core of intermediary-device function.- Networking hardware (Wikipedia) — defines switches, routers, access points, and firewalls and how they direct/forward traffic.