Question On Number Of Devices In A VLAN

Answered Question

I am looking at our server farm VLAN, and think we are getting close to some limitions. I have heard of a 50% rule, which in our case, a 22-bit should have no more then 512 devices in that VLAN. We are currently at 555 and they are getting ready to add about 60 more severs.


Is there such a rule/limitation?


I want to divide the current VLAN into a Medical Application VLAN and Office Application VLAN.


Any assistance on this would be appreciated.


Dave

Correct Answer by Jon Marshall about 9 years 7 months ago

Hi Dave


Different people give different answers and there are no hard and fast rules about this but i would not go above a class C for any vlan usually although a lot depends on the amount of broacast traffic on that vlan which can be applicaiton dependant.


On a server vlan i would generally look to use /25's at most although it does depend whether there is a logical separation in terms of function ie. you mention a medical application vlan and an office vlan.


if you can split the vlan up into these 2 functions then i would recommend you go down that route. Also there is nothing wrong with having 2 or 3 vlans each with it's own subnet range per function.


I would try to avoid using anything over a class C for pretty much any vlan but server vlans as suggested i would go down to /25's.


HTH


Jon



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Correct Answer
Jon Marshall Mon, 12/17/2007 - 23:33
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Hi Dave


Different people give different answers and there are no hard and fast rules about this but i would not go above a class C for any vlan usually although a lot depends on the amount of broacast traffic on that vlan which can be applicaiton dependant.


On a server vlan i would generally look to use /25's at most although it does depend whether there is a logical separation in terms of function ie. you mention a medical application vlan and an office vlan.


if you can split the vlan up into these 2 functions then i would recommend you go down that route. Also there is nothing wrong with having 2 or 3 vlans each with it's own subnet range per function.


I would try to avoid using anything over a class C for pretty much any vlan but server vlans as suggested i would go down to /25's.


HTH


Jon



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