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Comment by mcmatterson | Hacker News Reader

I fail to see how this is different than virtual bridges (ie: brn interfaces in linux). Such interfaces exist within the host OS in a virtualized environment, support 802.1q trunks, and exhibit quite a lot of flexibility. They're also fast (they're faster than I've ever had need for, though I don't know exact numbers offhand). Am I missing something, or hasn't this been done before?

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Among other things, the difference is speed: VALE can do 18 Mpps versus the 0.8 Mpps of a Linux bridge. And sometimes you do need speed, maybe not for virtual machines but e.g. if you want to stress test your network monitors, routers, IDS etc. For instance, using VALE we found out a missing event notification in QEMU/KVM which limited the receive speed to 50 Kpps, and a one-line fix brought it up to 1 Mpps.

Solaris 11 also has virtual networking and it doesn't suffer from those same performance issues:

  http://www.oracle.com/technetwork/server-storage/solaris11/technologies/networkvirtualization-312278.html

'Speed' is a good enough answer. I was mostly wondering if there was some fundamental difference that I wasn't seeing, or if it was just a better/faster implementation of the same thing.

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