Guest wireless - dhcp lease is 85% full

[mchockalingam]

Hi All,

I have guest wireless implemented using mobility anchor controllers in the DMZ. I have DHCP lease time set to 16 hours for the guest users. I only see about 400 to 500 guest users associated on any given day but the DHCP server which has about 2000 addresses shows 80 to 85% lease full.

I know some clients are not authenticated but are associated and they probably exhaust an IP address but I do not see more than 500 associated. Why am I seeing so many IP addresses being used?

Meena

[locp]

    With all the Ipad, Iphone and smartphones, I tune our lease to 4 hrs, assuming devices are leaving for lunch ...

   YMMV, so try it out .

  Loc

[mchockalingam]

At 50% of the lease expiration time, client will try to renew the IP again which is 2 hours in your case. Is it generating a lot of DHCP traffic?

Meena

[dmantill]

not really... not all the clients are connect for more than 2 hours... and iether if it is true not all client connect at the same time...

[George Stefanick]

Hi Meena,

(Is this Meena from TX)?

We have a large wireless guest deployment in the Med center. We experimented with different leases options. What worked for us was creating a large B size subnet with lease times at 2 hours. We show about 1000-1300 wireless clients at any point in time. HOWEVER, after doing a PING scan we normally show 200 or so actual guest on the network.

I hope this helps..

[mchockalingam]

Hi George,

Yes. It is me.

Thanks for your resposne. I wonder why we did not have this problem when we had the older BBSM in place. I never had any DHCP lease exhaustion issues. I never saw the DHCP server filled with lease/renew requests that I see with this new guest wireless. The DHCP server logs only go back up to 3 days beacuse of this. It used to have logs for months prior to this. Any ideas?

Meena

[dmantill]

nonwdays, there are alot of devices that uses WiFi... starting from Laptops. PDAs. ipods, iphone, smartphones, players, spiders... COWs... LOL etc...

[George Stefanick]

hummm how was your BBSM configured? Drop me a call on Monday. Lets discuss ...