Using VLANs for IPv6 site deployment is not really a transition tool but it is a method that is becoming more commonly used for dual stack IPv6 deployment in site networks because it is so easy if the network already makes use of the VLAN technique. One just injects (new) IPv6 subnets/links into the existing IPv4 VLANs. In a smaller size network, there may be 10-15 VLANs, each just carrying traffic for one IPv4 subnet. In such situations, one can take advantage of the VLAN segregation of traffic to connect IPv6 routers such that a single IPv6 prefix (a /64 prefix) is injected into each IPv4 VLAN that requires dual-stack networking. Hosts in such subnets can then autoconfigure IPv6 addresses in addition to their IPv4 addresses or make use of DHCPv6 if the service is implemented. In this case, the IPv6 routing hierarchy may be IPv6-only, and exist in parallel to the IPv4 network infrastructure. The IPv6 link offsite may also be separate.

It is important in such an instance that IPv6 filters and access control lists are deployed to prevent IPv6 being a back door for hackers to enter the (IPv4) network.

See [Cho04b], an IETF I-D produced within the 6NET project, for more details.