What is "hvlan"

Hierarchical VLAN (HVLAN) is a proposed Ethernet standard that extends the use of enterprise Ethernet VLAN (802.1Q) to carrier networks. A number of developments have emerged in recent years to help bring Ethernet, a flexible and cost-efficient packet transport technology, to carrier networks. These developments include Q-in-Q (802.1ad), PBB ( 802.1ah), PBT ( Provider Backbone Transport), and PBB-TE ( Provider Backbone Bridge Traffic Engineering), which bring a set of features to traditional Ethernet to make it “carrier-grade”, adding to it high-availability, OA&M, and more.

While attempting to retain the core features that made Ethernet attractive in the first place, these technologies do not address other inefficiencies that could limit their use in the long term. This is especially true when considering the expected significant growth of multipoint network applications – IPTV, Private LANs, gaming, and others. The delivery of such services is better supported by PBB and associated protocols than alternatives such as MPLS, yet could hit scalability issues should services evolve as predicted.

HVLAN introduces the concept of hierarchical addressing schemes into the VLAN tag to provide both enterprise and carrier transport networks the characteristics they need in the long run.