When several devices communicate with a Layer 2 broadcast domain DMZ, it is possible for a rogue device to introduce itself into a VLAN and cause serious security issues on the network. The previous solution to this problem was to assign a separate VLAN to each user. This resulted in a network that required many VLANs, was difficult to scale, and made IP address management more complicated. Using private VLANs (or PVLANs) addresses the Layer 2 security, without scalability issues, and provides IP address management benefits for service providers.