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While self-studying for a VMware Associate Certificate I'd see the phrase "Logical Switch" pop up from time to time, at first I figured it was a synonym for a virtual switch. Then I ran into a practice test question where the correct answers was that you needed a Logical Router Control VM to bridge Logical Switches to layer 2. This made me scratch my head as I thought a Logical Switch was just a virtual switch, and a virtual switch just connects a VM to the physical network, so I was like why is layer 3 getting involved? After scratching my head I started to research and found out that Logical Switch != Virtual Switch.

I then realized that there are at least 4 types of virtual switches:

  • vLAN = virtual layer 2 network (Lets you make a physical switch behave as if it were multiple physical switches or lets multiple physical switches behave as if they were 1 physical switch, also you can do a combination of both concepts at the same time)

  • Virtual Switch = software abstraction layer that allows VM to interact with the physical network.

  • Virtual Distributed Switch = Central management of several Virtual Switches.

  • Logical Switch = You can use VXLAN to do MAC to MAC encapsulation of layer 2 traffic, which can create a logical layer 2 network/layer 2 overlay network on top of a layer 3 network. So you could have a Logical Switch spanning between AWS cloud and Azure cloud / a layer 2 network spanning over layer 3 internet.

And I started to wonder if there were any other virtual switch concepts that are becoming industry standard virtual switch concepts/not vendor specific, that I missed being introduced to.

Thus the question:

What are the main virtual switch concepts that exist? Are there any beyond the 4 that I mentioned?

  • To clarify are there any virtual switch concepts besides vLAN, Virtual Switch, Virtual Distributed Switch, and Logical Switch? Hum I Might change the title to that. (from "What are the main virtual switches concepts that exist? (Logical Switch != Virtual Switch)" – neokyle May 9 '18 at 14:22
  • You are really treading close to on an off-topic question. Questions about host/server/VM configurations are off-topic here. – Ron Maupin May 11 '18 at 4:04
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A logical switch is a switch function implemented in software-defined networking. This isn't necessarily connected to VXLAN tunneling. Whether a logical switch is virtual or not is a matter of perspective.

A virtual switch is a (somewhat) more common L2 switch that's integrated in a hypervisor (or otherwise non-physical).

VLAN is no virtual switching concept but layer 2 virtualization (usually 802.1Q).

VXLAN is a layer-2-over-layer-3 tunneling protocol with inherent subtunnels. It not only relates to virtual or logical switches and is roughly a combination or L2 tunneling and VLANs.

There are many differences in virtual switches, e.g. VMware and Hyper-V vSwitches behave somewhat differently. One of the variant families is distributed vSwitches.

All in all, you seem to be throwing together technologies and terms for very different aspects. I think you should look at each of them and understand what they do and what they can be used for.

  • That's a definition for logical switch, but my reason for asking the question was to know if there's any other virtual switch concepts I don't know about, but probably should know about. – neokyle May 9 '18 at 13:52
  • This is a very broad question and I had the impression you weren't sure of the dfferences... – Zac67 May 9 '18 at 16:54
  • You seem to have changed your question quite a bit - I've expanded the answer accordingly. – Zac67 May 9 '18 at 17:06
  • Thanks for the answer, I basically just wanted help getting them straight in my head because as you say they are all technologies for very different things, but they all have virtual in the name and that's the part that was confusing to me. This helped clear things up for me. I especially like your definition of VLAN. – neokyle May 10 '18 at 13:49
  • Glad to help. ;-) – Zac67 May 10 '18 at 15:02

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