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Regular Contributor I
Posts: 173
Registered: ‎10-22-2010

Vlan Mobility - some queries on how it works.

Hi,

 

i have some about 6 vlans, pooled, with even vlan assignment. The controllers are in code 6.1.3.9.

 

there are about 3 controllers, with all these 6 vlans trunked to the common uplink switch.

 

 "vlan mobility" is not turned on as of now.

 

There are multiple entries of same mac-address across same vlan. and some same mac-address with different vlans, in the output of show datapath bridge table.

 

Reference: https://arubanetworkskb.secure.force.com/pkb/articles/HowTo/R-1452

 

By the above KB, if a controller, looks the show datapath bridge table, which record from the table will be taken for vlan assignment for the vlan-mobile client?

 

I am in doubt if enabling vlan mobility on a production vap, will be distruptive for the clients. Please advise on this as well.

 

I want to check if there is a way to clear the show datapath bridge table entries, so there would be new vlan assignments for the clients. please advise.

 

 

Guru Elite
Posts: 20,759
Registered: ‎03-29-2007

Re: Vlan Mobility - some queries on how it works.

[ Edited ]

The VLAN is chosen by the VLAN pooling algorithm, NOT the bridge table...

 

Vlan mobility has nothing to do with what VLAN is chosen in a pool.  If you choose "hash" the VLAN # chosen will always be the same.  Not so with the even pooling algorithm...

 

 



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Regular Contributor I
Posts: 173
Registered: ‎10-22-2010

Re: Vlan Mobility - some queries on how it works.

Thank you CJ. Then what is the purpose and function of vlan mobility? 

Guru Elite
Posts: 20,759
Registered: ‎03-29-2007

Re: Vlan Mobility - some queries on how it works.

Please search the knowledgebase at http://support.arubanetworks.com/KNOWLEDGEBASE/tabid/133/Default.aspx for "vlan mobility" for tons of information on the topic.  The most common use is if you have two different AP-Groups on the same controller where the Virtual APs have different VLANs configured--Enabling VLAN mobility will allow a client already in the user table, when it roams to an access point that has a VAP with different VLANs to keep the same VLAN...  That is probably the most common use...

 



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Regular Contributor I
Posts: 173
Registered: ‎10-22-2010

Re: Vlan Mobility - some queries on how it works.

Thank you CJ. So in my scnario of multi-controller environment, that is 1 master and 2 local controllers, with their uplinks trunking all the user vlans to a common L3 switch. I should not be using the vlan pooling by even assignment. I should use the hash assignment. Correct? Please advise.

 

 To note: My clients will be moving between APs on all the three controllers. 

 

 

Guru Elite
Posts: 20,759
Registered: ‎03-29-2007

Re: Vlan Mobility - some queries on how it works.

Yes.

 

If you have VLANs 3,4,5 on the first, second and third controller, using Hash, your client will always end up in the same VLAN...



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Regular Contributor I
Posts: 173
Registered: ‎10-22-2010

Re: Vlan Mobility - some queries on how it works.

Thank you CJ. To make my understanding better. 

 

I should use the even assignment in vlan-pooling, only when my topology is a standalone controller, correct? 

Guru Elite
Posts: 20,759
Registered: ‎03-29-2007

Re: Vlan Mobility - some queries on how it works.

It is not necessarily a best practice to that.



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Regular Contributor I
Posts: 173
Registered: ‎10-22-2010

Re: Vlan Mobility - some queries on how it works.

Thank you CJ. Would you be able to comment, on what may be impact if we have even vlan-pooling assignment, in a multi-controller(master-local) topology?. Where all the vlans are trunked down to a L3 switch, which does the DHCP relay. There are two DHCP servers in this network. where the dhcp scope is slipt and managed by each server. The dhcp scope in one server, is excluded in the other. 

Guru Elite
Posts: 20,759
Registered: ‎03-29-2007

Re: Vlan Mobility - some queries on how it works.

Is it even possible to roam from an access point on one controller to the other?



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

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