All

VXLAN: Millions or Billions?

Tony Bourke comments at The Data Center Overlords:

I was putting slides together for my upcoming talk and there is some confusion about VXLAN in particular, how many VLANs it provides.

The VXLAN header provides a 24-bit address space called the VNI (VXLAN Network Identifier) to separate out tenant segments, which is 16 million. And that’s the number I see quoted with regards to VXLAN (and NVGRE, which also has a 24-bit identifier). However, take a look at the entire VXLAN packet (from the VXLAN standard… whoa, how did I get so sleepy?):

vxlan

Tony’s amazing Technicolor Packet Nightmare

The full 802.1Q Ethernet frame can be encapsulated, providing the full 12-bit 4096 VLANs per VXLAN. 16 million multiplied by 4096 is about 68 billion (with a “B”). However, most material discussing VXLAN refers to 16 million.

So is it 16 million or 68 billion?

Read more at: VXLAN: Millions or Billions?

About the author

Stephen Foskett

Stephen Foskett is an active participant in the world of enterprise information technology, currently focusing on enterprise storage, server virtualization, networking, and cloud computing. He organizes the popular Tech Field Day event series for Gestalt IT and runs Foskett Services. A long-time voice in the storage industry, Stephen has authored numerous articles for industry publications, and is a popular presenter at industry events. He can be found online at TechFieldDay.com, blog.FoskettS.net, and on Twitter at @SFoskett.

Leave a Comment