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VLAN Pooling Issue on ZD3000 firmware

New Contributor II

I have a campus wifi setup consisting of the following:

(1) ZD3000 with 250AP licence running firmware
(200) ZoneFlex 7363
(15) ZoneFlex 7762
Cisco Catalyst 4507 R+E Sup 7-E Core Switch
Cisco Catalyst 2960 and 3560 10/100 PoE Access Switches

Number of users on the network 3000 ~ 4000

I have setup vlan pooling to eliminate using large subnets and avoid degraded network performance from broadcast and multicast traffic.

I setup (10) VLANS, 10,12,14,16,18,20,22,24,26 and 28 with ip scopes of 510 each (/23 networks) on the vlan pool list and enable dynamic vlan.

When I ran this setup in the campus, I experienced people complaining failure to connect to wifi and cannot grab IP.

When I looked at the Core Switch which is the DHCP server and searched the DHCP pool I saw that dhcp pool for Vlans 10, 12, 26 and 28 were completely exhausted (all ip leased). However, since I configured 10 Vlans on the vlan pool list, I was expecting that users will use be allocated to the other 6 vlans which where not yet used but after several hours the users were not allocated to the remaining vlan.

I have configured ports on the Core Switch for VLAN 14,16,18,20,22 and 24 just to check whether I can get IP from this DHCP pool on my pc and I did. These vlans are functioning properly and can get the IP from the DHCP server.

Have anybody experienced this issue before? Now I'm stuck and unable to figure out why the other vlans were used by the vlan pool list.

Note: From the VLAN Pooling List  vlans 10,12,14,16,18,20,22,24,26 and 28 were included
All my access switches has vlans 10,12,14,16,18,20,22,24,26 and 28 configured
All vlans 10,12,14,16,18,20,22,24,26 and 28 has DHCP scopes configured and are pointing to the correct vlan gateway (tested PC connected to Core Switch and confirmed can get IP using wired)

Any ideas?



Hello Tanski,

VLAN Polling by default uses the MAC Hash option for VLAN assignment. There are two more options and you can configure one of them and they are "Round robin" and "Least Used". 

Please check the following KB article and configure the 3rd option which is Least used and I think this should help:


hi Rahul,

we tried option 3 and we do notice that the users are now being distributed in the all the 10 configured vlans. thanks for the suggestion.

however, does this have any impact in roaming of devices in the network as opposed to using option 1?

also, around 3 hours after configuring above changes suddenly all the ap were dropping the connections and my core switch suddenly spiked to to 100% cpu. After shutting down most of the interfaces towards fhe acess switches to where the AP connects to and then enabling the ports one at a time, the access points reconnected back to the zd. not sure what has caused this but the only thing changed at that time is option 3 on the zd vlan pooling.



Hello Tanski,

This should not impact roaming.

Also it's hard to pin point what could have caused the APs to loose connection to ZD without the AP support info files. So I would suggest to open a case with Support if you see this again. We will need the AP support info files which you can extract from ZD UI, Monitor :: Access Points :: Action :: System info.

You can also extract the files from AP UI, Maintenance :: support info :: Save to local Computer.