This document discusses private VLANs (pVLANs) which provide isolation between ports within the same network. It defines primary and secondary VLANs, with the primary being the high-level VLAN and secondary VLANs belonging to its subnet. Secondary VLANs include community and isolated types. The document provides examples of configuring a switch into transparent mode and defining primary/secondary VLANs and their associations. It also gives configurations for assigning ports to promiscuous, community, and isolated pVLANs.