In this section, we will address some of the most common connectivity and performance issues that transpire on wired networks. As most of these issues exist at layer 1 and layer 2, higher-layer protocols will frequently exhibit issues as well when these problems exist, since these higher-layer protocols depend on the services offered by the lower layers. It is therefore recommended that technicians become familiar with the symptoms of these issues, and perform a bottom-to-top troubleshooting methodology when they suspect that these problems are present:
- Link lights/status indicators: Most equipment includes lights on each interface where links can be plugged into the equipment, which helps technicians to diagnose physical layer issues on those links. Lighting schemes differ between different vendors of equipment, but a lack of lights on an interface...
