Network Implementation: Routing, Switching, Wireless, and Physical Plant
Routing
Distinguish static routes from dynamic protocols. Distance-vector protocols choose by hop count or composite metric, while link-state protocols build a topology database and run shortest-path calculations; BGP carries routes between autonomous systems. Administrative distance decides between sources when multiple routes to the same prefix exist.
Switching
Access ports belong to one VLAN; trunk ports carry many VLANs with 802.1Q tags. Spanning Tree prevents Layer 2 loops by blocking redundant links, and RSTP converges faster. Link aggregation (EtherChannel/LACP) adds bandwidth and redundancy. Port mirroring feeds monitoring tools.
Wireless
Know the 802.11 family at a high level, the difference between 2.4, 5, and 6 GHz, and why 2.4 GHz channels 1, 6, and 11 are the non-overlapping set. WPA2 and WPA3 protect the air link; SSIDs identify networks and BSSIDs identify radios. Survey for coverage and interference before deployment.
Physical and services
Copper categories differ in supported distance and speed; single-mode fiber goes farther than multimode. Power over Ethernet has power budgets that must be checked per switch. NAT/PAT translates addresses at a boundary, and DHCP relay forwards requests across subnets.
Traps
A host in one VLAN that cannot reach a DHCP server in another usually needs an L3 gateway or router-on-a-stick, the VLAN allowed on the trunk, and a DHCP relay address. A native VLAN mismatch or a trunk missing the VLAN produces exactly this symptom. Wireless questions often mislead with channel width rather than channel overlap.
Worked example
Users in VLAN 10 cannot get addresses from a server in VLAN 20. Verify the SVI or subinterface for VLAN 10 exists, the trunk allows both VLANs, and the gateway interface carries ip helper-address pointing to the server. Test with a static address first to separate DHCP failure from routing failure.