Network Dictionary – oVLAN and uVLAN

When working in overlay & underlay networks, it’s a requirement to be able to differentiate between software VLANs in the overlay, and hard VLANs in the underlay.

When working in a VMware only environment, it’s common to refer to them as VLANs and VXLANS, but when writing about more general overlay networks you need to consider that protocols like NVO3 and NVGRE don’t make sense.

My answer is to the term oVLAN = Overlay VLAN and uVLAN =Underlay VLAN.

I’ve consider using pVLAN = Physical VLAN but this is already used for Private VLANS (PVLANS) and most people don’t get the point straight away.

I’d interested to hear what anyone else thinks about naming VLANs in the underlay and the overlay network. Getting a consistent language would help in my design meetings.

About Greg Ferro

Greg Ferro is a Network Engineer/Architect, mostly focussed on Data Centre, Security Infrastructure, and recently Virtualization. He has over 20 years in IT, in wide range of employers working as a freelance consultant including Finance, Service Providers and Online Companies. He is CCIE#6920 and has a few ideas about the world, but not enough to really count.

He is a host on the Packet Pushers Podcast, blogger at and on Twitter @etherealmind and Google Plus

You can contact Greg via the site contact page.

  • Den Borchev

    How about calling them Real VLANs (rVLAN)?
    In comparison, others are Imaginary.

  • Michael Gonnason

    Sounds rational

  • Rob Hirschfeld

    This makes sense to me too. Thanks for the suggestion

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