The unglamorous part.
WHY IT MATTERS
Network equipment fails from heat, power problems and physical damage more often than from anything technical.
POWER
Equipment should be on protected power.
Surges damage network equipment readily.
WHAT TO CONSIDER
A means of keeping the router and switch running through short interruptions.
That keeps connectivity while other equipment restarts.
COOLING
Equipment in an enclosed cupboard overheats.
Overheating produces intermittent faults that look like network problems.
WHAT TO CHECK
Ventilation around equipment Whether it is warm to the touch Dust accumulation
PHYSICAL PLACEMENT
Secure, ventilated, and not where it can be knocked or unplugged.
WHAT TO AVOID
Equipment on the floor Cables where they are trodden on Everything on one unprotected socket
WHAT TO LABEL
Cables and equipment.
WHAT TO CHECK PERIODICALLY
Physical condition, and that nothing has been moved or unplugged.