hub_switch_router
// How each device handles traffic — layer, collision domains, broadcast domains
Hub — Layer 1 (Physical)
Hub
A hub is a dumb repeater.
Full Comparison
FeatureHubSwitchRouter
OSI Layer1 — Physical2 — Data Link3 — Network
AddressingNoneMAC addressIP address
Collision DomainOne per hub (all share)One per port (isolated)One per port (isolated)
Broadcast DomainOne (all ports)One VLAN (all ports)One per interface
Forwarding methodFloods all ports alwaysMAC table lookupRouting table (IP)
DuplexHalf (CSMA/CD required)Full duplex per portFull duplex
Stores & ForwardsNo (repeats bits)Yes (checks errors)Yes (checks headers)
ConnectsDevices on same LANDevices on same networkDifferent networks
Speed impactDegrades with more hostsDedicated per portDedicated per port
Used today?No — obsoleteYes — everywhereYes — essential