roaming between three controllers

[Mohamed Sayed]

hi all,

I have three wireless controllers each one in separate subnet, each controlller has set of APs connected on it.

I configured mobility group between the three controller but when moving from specific AP on specific controller to another AP on another controller connecting by cisco wireless ip phone 7925 the call is dropped and the phone re-register again.

when roaming between different APs on the same controller, no problem occurs.

then the problem is in roaming between different controllers each one in different subnet.

appreciate your support.

please advice.

[Leo Laohoo]

The behaviour is to be expected.  This is why Cisco does not recommend inter-controller roaming if you are using voice/video application.  

Read this:  http://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/cuipph/7925g/7_0/english/deployment/guide/7925dply.pdf

[Mohamed Sayed]

hi all,

thanks alot for your reply 

Leo Laohoo, I donnot find that cisco not recommend inter-controller roaming please advice

Manannalage ras... thanks for your reply i will post the output of  "show mobility summary"  

but I need to know how can I solve this problem, as it is a big issue ???

thanks in advance

[Rasika Nayanajith]

Hi,

You have to provide some output to find what's missing in your configuration. First thing is to make sure mobility tunnels are up between controllers. Then I would check all controllers are having same virtual IP address as well.

Here is reference post about L3 roaming, hope it is useful.

http://mrncciew.com/2013/03/17/l3-inter-controller-roaming/

Regarding Leo's response, Cisco is recommending to have intra-controller roaming where possible (ie all nearby buildings AP should go to same controller). This will help to optimise client roaming & reduce unnecessary delays).

Still L3 roaming is perfectly working even though roaming could take little bit extra time. 

HTH

Rasika

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[Mohamed Sayed]

Hi Manannalage ras...,

you mean now I must configure one of the three controller as anchor and the other two as foreign for the voice SSID to excute layer 3 roaming ??

if yes , if there is a client associated on foreign controller, can it roams smoothly to the anchor ??

appreciation  

[Rasika Nayanajith]

When configuring mobility you simply need to configure same mobility group name in your 3 controllers (do not worry about which one become anchor or which one is foreign at any given time). Below provide some configuration steps involve.

http://mrncciew.com/2013/03/16/configuring-mobility-on-wlc/

When a client associate first time to an AP managed by a controller, that controller act as "Anchor" for that client when client roams to another AP managed by a different controller (become "Foreign" controller for that client).

yes, when controllers are in same mobility group & each controller configured for same SSID, clients can roam seamlessly between any APs managed by those controllers.

Pls provide requested output to see what's going on

HTH

Rasika

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[Mohamed Sayed]

you mean that the Anchor, foreign controller will be configured by default after configuring the mobility group ??

I already configured a mobility group by these steps and the roaming between the controllers fail 

[Rasika Nayanajith]

"Anchor" & "Foreign" controller is a relative concept & depend on client first association to the network. You do not want to configure it (do not confuse with auto-anchor of a WLAN)

Let's say a client associated to AP1 managed by WLC1. Now if client move to AP2 managed by WLC2 (let's assume WLC are layer 3 separated) then client database entry copy from WLC1 to WLC2. In the WLC1, it will be labelled as "Anchor" & in WLC2 it will be labelled as "Foreign" for that client. Since client has to keep its IP traffic has to tunnel from Foreign to Anchor. If client had a ongoing session while roaming, it will not drop/disturb provided continuous wireless coverage is there.

In your case, due to some reason, this is breaking, indication mobility is not working properly. 

Let's troubleshoot it. so first get into those controllers via CLI & provide that "show mobility summary" output

HTH

Rasika

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[Mohamed Sayed]

auto-anchor technology cannot solve the problem ???

I will go to the customer and get the output of " show mobility summary " and post it.

thanks in advance

[Rasika Nayanajith]

No, typically auto-anchor feature is used to termniate a particular WLAN traffic to a single WLC. Normal use case is "Guest traffic" where you want to terminate in a DMZ.

In your scenario it is normal mobility configuration is required. If you have to go to customer place to get that output take all the below output in one go.

1. show mobility summary

2. show interface summary

3. show wlan summary

Then enable "debug client <MAC Addr>" on all your controller where MAC addr is your 7925 MAC. Associate  7925 to AP1 (manage by one WLC) & move onto AP2 (managed by a different controller). Pls attach those debug output as well.

I would also encourage to see that overlapping coverage is there between AP1 to AP2

P.S: AP1 & AP2 given as example, you may need to find similar APs at customer environment

HTH

Rasika

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[Mohamed Sayed]

(WiSM-slot2-1) >show mobility summary 

Mobility Architecture ........................... Flat
Mobility Protocol Port........................... 16666
Default Mobility Domain.......................... CC-MG
Multicast Mode .................................. Enabled
Mobility Domain ID for 802.11r................... 0x4f6f
Mobility Keepalive Interval...................... 10
Mobility Keepalive Count......................... 3
Mobility Group Members Configured................ 5
Mobility Control Message DSCP Value.............. 0

Controllers configured in the Mobility Group
 MAC Address        IP Address       Group Name                        Multicast IP     Status
 00:07:7d:0b:13:60  xx.xx.xx.xx     CC-MG                             239.1.1.100      Up
 00:07:7d:0b:13:c0  xx.xx.xx.xx     CC-MG                             239.1.1.100      Up
 00:07:7d:0b:15:40  xx.xx.xx.xx     CC-MG                             239.1.1.100      Up
 2c:54:2d:3a:31:20  xx.xx.xx.xx       Etisalat-MG                       0.0.0.0          Up
 2c:54:2d:3a:31:40  xx.xx.xx.xx       Etisalat-MG                       0.0.0.0          Control and Data Path Down

*********************************************************************************

(WiSM-slot2-1) >show interface summary 

 Number of Interfaces.......................... 9

Interface Name                   Port Vlan Id  IP Address      Type    Ap Mgr Guest
-------------------------------- ---- -------- --------------- ------- ------ -----
cc1-voice                        LAG  777      xx.xx.xx.xx     Dynamic No     No   
management                       LAG  778      xx.xx.xx.xx    Static  Yes    No   
redundancy-management            LAG  778      0.0.0.0         Static  No     No   
redundancy-port                  -    untagged 0.0.0.0         Static  No     No   
service-port                     N/A  N/A      xx.xx.xx.xx    Static  No     No   
vf-control                       LAG  850      xx.xx.xx.xx   Dynamic No     No   
vf-eap-sim                       LAG  851      xx.xx.xx.xx     Dynamic No     No   
vf-non-eap-sim                   LAG  852      xx.xx.xx.xx    Dynamic No     No   
virtual                          N/A  N/A      1.1.1.1         Static  No     No  

*****************************************************************************************

(WiSM-slot2-1) >show wlan summary 

Number of WLANs.................................. 6

WLAN ID  WLAN Profile Name / SSID               Status    Interface Name        PMIPv6 Mobility
-------  -------------------------------------  --------  --------------------  ---------------
1        Voice / Voice                          Enabled   cc1-voice             none    
2        Etisalat_Hotspot / Etisalat_Hotspot    Enabled   management            none    
3        Etisalat_WiFi / Etisalat_WiFi          Enabled   management            none    
4        CityStars / CityStars                  Enabled   management            none    
5        CityStars-VodaFone2 / CityStars-VodaFone2  Enabled   vf-eap-sim-grp        none    
6        CityStars-VodaFone1 / CityStars-VodaFone1  Enabled   vf-non-eap-sim        none 

appreciation

[Rasika Nayanajith]

Hi

Thanks for the input, I assume CC-MG is the mobility group configured for controllers you are concern.

I can see multicast mode enable for Mobility. Is multicast properly configured in your switch network ? I would check WLC management vlan (778) is PIM enabled & multicast is working properly.

If you do "show ip mroute 239.1.1.100" on these WiSM connected 6500 , would you see multicast traffic is correctly forwarding to WLC management vlan interfaces ?

If you are not sure about multicast configuration then I would suggest to change it to unicast for a test. You can disable multicast mode for mobility like below in your controllers.

(WLC) >config mobility multicast-mode disable 

(WLC) >config mobility group multicast-address CC-MG 0.0.0.0

In this way if roaming works, you have multicast configuration issue of your switch network.

Give it a try & do this test & let me know.

Take those debug outputs in current scenario & once you disable the multicast mode to compare.

HTH

Rasika

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[Mohamed Sayed]

hi Manannalage ras...,

I changed the multicast to unicast as you told me and the issue has been solved :) 

but I need to ask you why this multicast configuration made a problem ?

[Rasika Nayanajith · Accepted solution]

Hi 

That's great & it proved that your network multicast is not configured correctly. Hence mobility communication broken since your WLC previously rely on multicast for WLC mobility.

It is NOT WLC mobility multicast configuration caused the issue. Your switch network multicast has not properly configured.

If you want to troubleshoot your switch network multicast, please follow this post & see whether you can use it for find the root cause for multicast failures.

http://mrncciew.com/2013/01/19/pim-sm-static-rp-configurations/

If you get your switch network multicast working, then I prefer you switch back to "Multicast Mode" for your WLC mobility configuration.

If you are satisfy with the resolution I have provided in the previous response please mark this thread as answered.

If you like to troubleshoot multicast config issue we can do that as well  

HTH

Rasika

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[Leo Laohoo]

Forgot another thing, make sure all your 792xG phones are running a minimum firmware of 1.4(3) and later.  Older firmwares have difficulty with roaming.