How it works
A small office or home network is built from a handful of parts: something that connects onward, something that joins local devices, and something that provides wireless access. One box often performs several of these jobs.
Identify which function is failing rather than which box. A device that reaches other local machines but nothing beyond them has a working switch function and a broken path onward.
Common error
Because one appliance often does everything, it is easy to conclude the whole network is broken when only one of its functions is.
Worked example
An office printer is reachable locally while all users lose access to outside sites. Distinguish the roles in the network.
Evidence
Workstations -> switch -> router -> upstream network
Printer -> switch
Local printing: works
External sites: unavailableThe switch still supports local communication. Investigate the router, upstream link, and associated configuration rather than replacing the functioning local switch first. A wireless access point provides radio access; it is not automatically the component routing traffic outward.
Exercises
2.1.1
Explain which device function forwards traffic between two IP subnets and which connects wired devices within one LAN.
Show solution
A router or routing-capable gateway forwards between IP subnets. A switch connects local Ethernet devices and forwards frames within the relevant local network.
2.1.2
A home gateway combines routing, switching, and wireless access. Why should an incident record identify the failed function rather than only name the box?
Show solution
One enclosure can continue switching local traffic while its upstream or wireless function fails. Naming the function directs testing and avoids treating every service provided by that appliance as broken.