VLAN for wireless? Do we need it?

[sidewinder]

We have a completely flat network at the minute. VLANing is something I want to do at some point but my knowledge of it is extremely sketchy and I dont want to rush into it until I know what I'm doing.

However we had an Aruba system installed this year and had some problems with coverage. The company that supplied it has been helping us sort it with a variety of things, and it has improved considerably. The last thing on their list, and the thing that hasnt been done yet, is a seperate VLAN for wireless.

They will set it up, and Im sure it'll work fine, but Im a bit uncomfortable about something being set up on our network that I dont really understand - kind of puts us in the sh1t if anything goes wrong. Im sure the engineer would explain it to me but Im still unsure.

The proposal is to VLAN our core switch, and have a seperate DHCP scope with a different address range for wireless clients. And the AP's will be on a different VLAN. I assume routing will be done between the VLAN's to allow the clients to communicate with the network.

But...how will a switch know which VLAN to assign a AP to? Will it need to be in a specific port? Do we need to make changes to all our edge switches? He seemed to say that we wouldnt.
And how on earth will the seperate DHCP scope work? How will the clients get assigned these addresses??

Im really not comfortable with all this, and Im tempted to call it off as we've had such an improvement in the wireless without it, it doesnt seem necessary, but then this engineer obviously knows better than me...doesnt he?

[KWestos]

If everything runs as you want it to, why change. What REAL benefits will you get from VLAN'ing. Yes, it will route more efficiently etc. But at the expense of worrying you, no!

Just stick with what you have. If problems arise, do it then.

[tmcd35]

'If it ain't broke don't fix it'

I'd agree with KWestos, unless you have a requirement for using a VLAN - don't do it.

The typical reason for VLAN'ing wireless AP's is when they support multiple SSIDs. You can have one SSID on one VLAN that is completely open. Student can bring in laptops and gain internet access. Then another, closed, SSID for school equipment on another VLAN that has full regular access to the network.

If you're not going for that kind of solution, why do it? Like you say it only confuses matter when something goes wrong later down the line.

[TheLibrarian]

How many devices do you have attached to that flat network?

I tend to work on ~200 per subnet to keep broadcast traffic to reasonable levels.

[sidewinder]

Thanks guys, glad its not just me then. It does seem the sensible choice for now.

How many devices do you have attached to that flat network?

I tend to work on ~200 per subnet to keep broadcast traffic to reasonable levels.

Around 500 desktops and then upto 400 laptops, but obviously they are never all on at once.
It is too much for a flat network I know, but we dont experiance any slowdown, and wireshark doesnt indicate excessive broadcast traffic.

[TheLibrarian]

If it's working then leave it would be my advice.

Although the less traffic to pass across the wireless the better I suppose, so a VLAN could be a very good idea.

I can't decided if I want to be decisive or not...