Reading IEEE 802® Standard for Local and Metropolitan Area Networks: Overview and Architecture document i came upon thins:
An IEEE 802 LAN is a peer-to-peer communication network that enables stations to communicate directly on a point-to-point, or point-to-multipoint, basis without requiring them to communicate with any intermediate stations that perform forwarding or filtering above the PHY. LAN communication takes place at moderate to high data rates and with short transit delays, on the order of a few milliseconds or less.
I couldn't understand the PHY part. Given that switches forward packets at the DLL, am I right to conclude that a network switch could separate my home network in two LANs?