AP addresses via WLC's DHCP server in version 4.0

[johnruffing]

One of the new features of version 4.0 is that the AP addresses can be assigned via the WLC's internal DHCP server. I have been unable to find anything about this in the 4.0 Configuration Guide.

Another observation:

Also, when setting up DHCP, the settings to not appear to be copied over to other WLCs in the same mobility group.

Does this imply that if the WLC with the DHCP server goes down, there will be no DHCP services available?

[Stephen Rodriguez]

Yes, you will need to configure the DHCP pool on all controllers that you want the clients to use. Remember though, that unlike a DC, you can't specify it's a shared supernet or not, so no backup.

[johnruffing]

What about how to setup the WLC so that the APs get their IP DHCP addresses from the WLC's DHCP controller?

Has anyone tried this yet with version 4.0?

[MICHAEL SCHROEDER]

Hi, i think you will be always safe and more flexibel if you use an external DHCP Server, for the AP?s maybe the Server offered by your L3 IOS Device. For Controller Join i prefer to use DNS Resolution, it?s IMHO easier to configure compared to DHCP Option 43 and VSA. Regards, Michael

[Stephen Rodriguez]

Once again, if the AP manager is directed to the management interface, it should give out an address, even to the AP.

[johnruffing]

Thanks for the great input.

I believe that we are going to go with an external DHCP server since this offers higher DHCP availability (due to the fact that the DHCP server on one WLC is not present on other DHCP servers within the same mobility group.)

- John

[c.fuller]

I think this thread answers my question.   But I just want to get it clarified.   Is it possible to use the internal DHCP feature on two WLCs to provision one DHCP pool at the same time?   For example, if I put two anchor WLCs on the DMZ and want them both to serve IPs from that one DMZ subnet is this possible.  I don't think it's possible and this thread seems to confirm that.  But just want to get further clarification before looking at other design options. 

Regards

Chuck

[George Stefanick]

Of course you can .... Just split the scopes between the controllers.. Say fornt end of the scope on WLC1 and the back end of the scope on WLC2. Point the controllers DHCP server to itself and you should be good.

I will mention, I am not a BIG fan of DHCP on the WLCs.

[Leo Laohoo]

I will mention, I am not a BIG fan of DHCP on the WLCs.

I'm with George.  I'm no big fan of using the WLC as a DHCP server at all.

[c.fuller]

Doh!  So simple, yet I did not even consider it.  Splitting the scope would be the perfect solution.   Thank you both.  

Question, I have been using WLC DHCP for about 3 years now on two anchor WLCs serving about 300 clients a day between them.   Both serve up different scopes each for a different campus.   I have never had any issues.  In fact during my testing it seemed that the WLC DHCP provided IP address faster than the external solution I was testing with (Cisco IOS DHCP).   I'm inclined to stick with WLC DHCP given it's reliability and performance over the past 3 years.  

What specifically do you not like about WLC DHCP?  Have either of you experienced issues with it?   

Chuck

[George Stefanick]

What code are you using ? There was DHCP issues in 7.0.98.0 and I also understand they had problems in 6.x. The problems I had was with the leases themselves. They would get all funky.