WLC 5520 some (not all) clients get ip 0.0.0.0, ext. DHCP,

[Abdullah2u]

Hi all,

I've problem with a WLC 5520. few Clients an IP 0.0.0.0.

Software Version is 8.5.140.0 

Around 30% are not OK.

The problem is,  we are testing on our secondary wlc all AP are moving in Secondary WLC perfectly but the few client that don't get a IP address or stuck in 0.0.0.0 until we restart the AP, after restart the AP the all clients get a ip from dhcp.

We are not using DHCP in this WLAN and DHCP is not configured in the wifi profile as well as in the controller advanced settings.

Right now , The clients are connected correctly, but they got a disconnect sometimes, which we can not clarify at the moment.

[Abdullah2u]

Its N+1 (two controllers) but not completely HA because one wlc is another location or second one is other .

mobilty between two controllers is establish in  my case???

if this is mobility issue why this issue suffers few clients not all clients???? 

[Scott Fella]

You need to understand what mobility does and what happens when mobility is not configured.

Number one rule is if aps will move from one controller to another and possibly there will be a mix of aps associated to one or another, then mobility needs to be configured. If the design is FlexConnect central switching, you definitely need mobility configured. This is how the technology is suppose to be implemented to ensure stability. The reason you see what you see is because devices are black holed and eventually will try again to connect and possibly would get a new ip. If you were to be connected to an AP and then you move that over to the other controller, you would see a connection issue.

[Abdullah2u]

• I checked vlan mapping  perfectly done on all flex connect group .
• The design is FlexConnect central switching.
• All AP 's IP address assign is static (each Flexconnect group has different dhcp pool or vlan)

further , im testing with your response mobilty is must configured in flex connect central switching,

once mobilty configured then im moving Ap's from one controller to another but im little bit confused,  right know  im stable in one controller and im facing the issue again client obtain ip  adress 0.0.0.0. may  be this is not the issue of mobilty group because all ap in one controller or the client response is same.

[Scott Fella]

I don’t know. I provided as much info as I can without reviewing any configuration. You should open a TAC case so they can look at the controller settings and logs.

[Leo Laohoo]

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@Abdullah2u wrote:

The problem is,  we are testing on our secondary wlc all AP are moving in Secondary WLC perfectly but the few client that don't get a IP address or stuck in 0.0.0.0 until we restart the AP, after restart the AP the all clients get a ip from dhcp.

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Like what said, this is N+1?

1.  Check that allowed VLANs are the same; 

2.  Make sure the dynamic VLAN IP address, subnetmask, gateway and DHCP are all the same.

[Abdullah2u]

Yeah, its N+1 onmy two controller, all ap are in FlexConnect mode, each FlexConnect group have different vlan and differnt dhcp poorl for users.

[Scott Fella]

You know that there is no Layer 3 roaming on FlexConnect. The SSID A needs to be on the same subnet or else things break. 

[Abdullah2u]

Ssid need to be sane subnet? Please elaborate 

[Scott Fella]

FlexConnect local switch doesn’t support layer 3 roaming. This is well documented in the FlexConnect design guide.  Only in central switching and or local mode layer 3 roaming is supported.  

[Abdullah2u]

Didn’t get your point,

where i can implement layer 3 roaming?

[Scott Fella]

 Select or unselect the VLAN based Central Switching check box to enable or disable central switching on a locally switched WLAN based on AAA overridden VLAN.Note    These are the guidelines and limitations for this feature:VLAN based central switching is not supported by mac filter. Multicast on overridden interfaces is not supported. This feature is available only on a per-WLAN basis, where the WLAN is locally switched. IPv6 ACLs, CAC, NAC, and IPv6 are not supported. IPv4 ACLs are supported only with VLAN-based central switching enabled and applicable only to central switching clients on the WLAN. This feature is applicable to APs in FlexConnect mode in locally switched WLANs. This feature is not applicable to APs in Local mode. This feature is not supported on APs in FlexConnect mode in centrally switched WLANs. This feature is supported on central authentication only. This features is not supported on web authentication security clients. Layer 3 roaming for local switching clients is not supported

https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-3/config-guide/b_cg83/b_cg83_chapter_0101101.html

[Abdullah2u]

In my case both flexconnect local switching and vlan based central switching box is unchecked 

[Reginald Pugh]

Did you resolve this- getting something similar: It takes an AP reboot for client to get a DHCP address , this is random, Some clients are connected yu have blue light on AP and others won't get the DHCP though they pass through ISE (AAA) with AnyConnect NAM : centralized auth . All APs they are in FlexConnect mode , with local switching. Code version 8.5.135.0,  

[patoberli]

Upgrade the WLC first, there were many bugs fixed in the newer two releases.

[Reginald Pugh]

I assume you are meaning 8.5.140.0 or 8.5.151.0. Those have a possible fix ? Will read the release notes.