I have typically known 'flat network' to be a non-vlan network, typically a single /24. We have a new hire (security analyst) at my company and he asked the desktop support supervisor if he had "trouble getting your job done on this flat network". I'm a bit unsure how he means this, unless he is referring to it being a layer 2 domain as opposed to a routed site. Currently the site in question is multiple vlans, each in it's own /24 with the site as a /16. It's all L2, except for intervlan routing in the core.

Am I wrong in my usage of 'flat network', or am I missing something here?

  • 1
    I know there isn't an official definition, and that was part of the issue I was having. Security segmentation does make sense, now that I think of it. Commented Apr 19, 2016 at 3:45
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide your own answer and accept it.
    – Ron Maupin
    Commented Aug 7, 2017 at 15:19

1 Answer 1


There is no official definition, and it means different things to different people. In general, the term, "flat network," means that the network isn't hierarchical (network engineer definition), or it is not security segmented (security engineer definition). You could have multiple VLANs all terminating in a single layer-3 device, and some consider that to be a flat network.

Networks with hierarchies and/or security segmentation aren't usually considered flat networks, but it depends on the audience.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.