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Community Member

VLAN Usage

Are there a set of general guidlines for using Vlans i.e., how many devices on a LAN before you should split them into Vlans?

Hall of Fame Super Blue

Re: VLAN Usage


This is a question that gets asked quite often and there is no definitive answer to this. It depends on your applications, how much broadcast traffic there is on the LAN segment, security issues such as having separate groups of people in separate vlans.

At the very least i would look to have your servers in a separate vlan than your client machines.

Consensus seems to be a class C ie 254 hosts is about right for the maximum. Personally we use /25's ie. half a Class C per vlan.



Community Member

Re: VLAN Usage

Thanks Jon, That's always been my rule of thumb but trying to convice some of the people around here is like beating my head against a brick wall. I guess what I'm really looking for is any hard documentation that says what you just said to prove to them that 800 devices on a flat network is not a good things.


Re: VLAN Usage

Also vote for a /24 group , thats the most manageable and gives the best performance without problems , of course you will always runn into certain situations where maybe you need a /23 or have to run secondary addresses on the same subnet.

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