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Access network design for branch, remote, outdoor and campus locations with Aruba access points, and mobility controllers.
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LMS Failover Dilema

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  • 1.  LMS Failover Dilema

    Posted Jul 08, 2013 01:35 PM

    Hey all,


    So I did a fair bit of reading before posting this and I couldn't find anything that would answer my questions, so let me define what my dilema is:


    1. I have two locations that we'll call "A" and "B".

    2. "A" location has 4 people and a controller with 4 APs.

    3. "B" location has 100+ people and 11 APs.

    4. "A" location has an Aruba 3400 controller that terminates both "A" and "B" APs.

    5. The controller has both AP groups listed on it

    6. Each location has its own subnet, 10.A and 10.B

    7. The controller has an IP address of 10.A


    The goal is to move the controller from "A" to "B", and this is the proposed way of doing it:


    (assume LMS failover is in place)

    1. Change all VLAN interface IPs (except the main management IP address) to match the NEW location (10.B instead of 10.A)

    2. Change the main VLAN IP from 10.A to 10.B (and lose ability to http, telnet, or ssh to it)

    3. Check LMS to assess fail-over

    4. Physically move the controller from "A" and plug it into one of the switches at "B"

    5. Check to see if we can log into the controller at new location (with 10.B IP)

    6. Access aruba-master and re-provision the APs to the correct AP group (in theory)


    The strangest part is that since the original controller's IP address will be changing, how are the APs going to know which controller to re-associate with? If the APs fail over to the aruba-master controller, how can I push them to the new controller? It might be easier to know how to tell the APs to associate with the AP-Group on the controller with the new IP address, since the APs are now on X AP-Group terminating at controller 10.A, when I need them to terminate to X AP-Group at controller 10.B.


    I might be making this more complicated than it needs to be, but I figure that someone here might know. Also, I'm sure that I'm going to need to clarify something, so please, ask away.


    Thank you!


  • 2.  RE: LMS Failover Dilema

    Posted Jul 08, 2013 01:53 PM

    You could do the following :


    1- Add the new VLAN B (interface) to the controller (make sure that the APs on each segment A and B are able to reach it, from the AP console you can run a ping)

    2- Change the LMS primary to the new IP address (don't write mem)

    3- If the APs find the controller through aruba-master , update the dns entry after step two (The APs only use this when booting up)


    (controller) (config) #controller-ip ?
    loopback Set to loopback interface
    vlan Set to VLAN interface

    5- Once the APs reboot they will look for the new IP



    Hope it helps

  • 3.  RE: LMS Failover Dilema

    Posted Jul 08, 2013 02:24 PM

    Hey vfabian,


    Thanks for the fast response. I'm going to reply to each of your "bullet" points here.


    1. It's the same VLAN for both locations, just a different IP address. The way it works is like this; start with the first segment, 10., and then put the location number, X., and then the vlan management subnet, Y., and then Z (static value). So, what we have is at location A, it'll be 10.A.N.Static, but then it'll change to 10.B.N.Static, both on the same VLAN. Each location is scoped according to its location (if that makes sense).


    2. I can't touch any of this since they're production applicances, and our test lab is being utilized by 3 different teams, so I'm stuck on this one.


    3. The APs normally find their controller based off of the subnet that they're getting DHCP / DNS from, so they only go to aruba-master if they can't find the controller on their subnet.


    4. Ok, this I can do.


    5. Ok, this is what I'm hazy on. If I change the IP of the controller that the APs terminate to (from both locations, physically disconnected), the APs should find the new controller, however, I don't think that the APs that are at the disconnect location will find them, so they'll probably default to Aruba-Master, and then I'll have to reprovision them to the appropriate controller, correct? I may need to draw this out.

  • 4.  RE: LMS Failover Dilema

    Posted Jul 08, 2013 10:48 PM

    I noticed you mention that you are trying to use a new controller , is this correct ? Or when you say a new controller you just mean a new IP address for the same controller ?

    Do you have any available down time to apply these changes ?

    Is the controller at a remote location that you cant console to it ?

    What do you mean by disconnect location ?

  • 5.  RE: LMS Failover Dilema
    Best Answer

    Posted Jul 08, 2013 11:04 PM

    Hey vfabian,


    I was actually able to come to a solution, and I thought I would share.


    I have location A which has a controller, but only 4 APs and 4 users. That same controller is the termination point for another location, which has more than 100 users and 11 APs. So, bad spot for it geographically.


    I'm going to do what you said and assign the LMS IP Address to the new locationally scoped one, change the management vlan IP to the new location scope, and then shut down the port on the switch and allow the APs to fail over to aruba-master. Once this is done, I'll have someone snag the controller, move it to location B, power it up, and see if the APs reassociate (they should). I think that's the best way to do it.


    Thanks for your earlier suggestions. I just want to point out that everything you suggested was in the VRD that I read today, so excellent work on remembering and recommending best practices. :)



  • 6.  RE: LMS Failover Dilema

    Posted Jul 08, 2013 11:12 PM
    Glad it worked out