Cisco LAN Switching Fundamentals

Private VLANs

Common VLAN implementation allows for any-to-any communication. Each host on the VLAN can communicate with any other host on that segment. Preventing communication between hosts on the same VLAN requires moving the users off the VLAN to their own separate VLANs. In the past, VLANs generally had a homogenous pool of users. The users in the VLAN had some type of commonality that allowed them to share the same resources and have the same access on the network. As a result, there was no need to filter traffic between users on the same segment. For instance, vendors or contractors who needed onsite access to the customer network were typically segregated in their own VLAN. Scalability was not an issue because the number of these groups ...