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Frequent Contributor II
Posts: 135
Registered: ‎07-06-2012

Master/Master (active-active) using VRRP and LMS

Hello All,

 

I just have a couple of questions before I start my understanding of configuring Master/Master in (Active-Active) and Master/Local

 

- in Master/Master deployment do they syncronize the configuration or I have to configure each controller separately ?

 

- what is the default value of VRRP priority ? is preempt enabled by default ? if not how can I enable it?

 

- can LMS IP address refer to a Master controller ?

 

- is there a different between AP reboot and AP rebootstrap ?

 

- in a master/master configuration if the the active master goes down will the AP reboot and request an IP address again and use ADP and re-install the configuration ?

 

- in Master/Local deployment if the AP connected and working normally on the local controller, suddenly the Master controller went down, will the AP continue operation or will it restart or fail ?

 

 

- if I have two MC in layer 2 and APs in layer 2 using ADP, will the APs connect to both MC or they will just pick one (first/last) or will not connect to any ?

 

==========================================

 

I was thing about having two master controllers working as Active-Active when they are in different subnets.

 

MC-1 (Subnet-1)  --- MC-2 (Subnet-2)

 

 

using LMS:-

 

1- On MC-1 configure AP-group with LMS= MC-1-IP-address in subnet-1

2- On MC-1 configure AP-group with LMS-backup= MC-2-IP-address in subnet-2

3- On MC-2 configure AP-group with LMS= MC-2-IP-address in subnet-2

4- On MC-2 configure AP-group with LMS-backup= MC-1-IP-address in subnet-1

 

using VRRP:-

 

create two AP-groups in each controller, create two VRRP instances between the two controllers.

 

MC-1 (Subnet-0) Active: (IP-add1) SB: (IP-add2)  --- MC-2 (Subnet-0) Active:- (IP-add2) SB:- (IP-add1)

 

1- On MC-1 configure AP-group-1 with LMS= IP-add1

2- On MC-1 configure AP-group-1 with LMS-backup= IP-add2

3- On MC-1 configure AP-group-2 with LMS= IP-add2

4- On MC-1 configure AP-group-2 with LMS-backup= IP-add1

5- On MC-2 configure AP-group-1 with LMS= IP-add2

6- On MC-2 configure AP-group-1 with LMS-backup= IP-add1

7- On MC-2 configure AP-group-2 with LMS= IP-add1

8- On MC-2 configure AP-group-2 with LMS-backup= IP-add2

 

the tricky point here is that because this is a layer-2, AP using APD can connect to any of the two MC therefore, you have to find to which MC the AP registered with and assign it to the correct AP-group then MC will sync!

When single MMC goes down AP associated with it will shift to the second MMC.

 

I do not know if this will happen; therefore I put it here to have confirmation and more information if this will work and that MCs will sync APs assignment on Ap-groups. 

 

 

 

Guru Elite
Posts: 20,990
Registered: ‎03-29-2007

Re: Master/Master (active-active) using VRRP and LMS

Please see answers <INLINE>

Abi wrote:

Hello All,

 

I just have a couple of questions before I start my understanding of configuring Master/Master in (Active-Active) and Master/Local

 

- in Master/Master deployment do they syncronize the configuration or I have to configure each controller separately ?

 

<They synchronize all WLAN configuration.  Individual items like VLANs and ip addresses, SNMP read strings need to be configured on each controller>

 

- what is the default value of VRRP priority ? is preempt enabled by default ? if not how can I enable it?

<The default Value is 100.  Preempt is NOT enabled by default.  Preemption is part of the VRRP configuration>

 

- can LMS IP address refer to a Master controller ?

 

<Yes, but in a master-backup master scenario, it usually points to the VRRP or HA address between them.>

 

- is there a different between AP reboot and AP rebootstrap ?

 

<Bootstrap is the search for another controller, usually when the AP loses contact with the first one.  Reboot is a complete reboot of the AP>

 

- in a master/master configuration if the the active master goes down will the AP reboot and request an IP address again and use ADP and re-install the configuration ?

 

<If the LMS-IP or aruba-master  is pointed at the VRRP IP, which is a best practice, the AP will simply continue transmitting traffic, once the back up master takes control of the VRRP>

 

- in Master/Local deployment if the AP connected and working normally on the local controller, suddenly the Master controller went down, will the AP continue operation or will it restart or fail ?

 

<The AP will continue working>

 

 

- if I have two MC in layer 2 and APs in layer 2 using ADP, will the APs connect to both MC or they will just pick one (first/last) or will not connect to any ?

 

<The AP will send an ADP broadcast and attempt to connect to the first one that answers.  It is up to the administrator to configure the LMS-IP to the VRRP, so that the AP is redirected to the high availability address, after it connects to the first available controller>

 

==========================================

 

I was thing about having two master controllers working as Active-Active when they are in different subnets.

 

 

 

MC-1 (Subnet-1)  --- MC-2 (Subnet-2)

 

 

using LMS:-

 

1- On MC-1 configure AP-group with LMS= MC-1-IP-address in subnet-1

2- On MC-1 configure AP-group with LMS-backup= MC-2-IP-address in subnet-2

3- On MC-2 configure AP-group with LMS= MC-2-IP-address in subnet-2

4- On MC-2 configure AP-group with LMS-backup= MC-1-IP-address in subnet-1

 

using VRRP:-

 

create two AP-groups in each controller, create two VRRP instances between the two controllers.

 

MC-1 (Subnet-0) Active: (IP-add1) SB: (IP-add2)  --- MC-2 (Subnet-0) Active:- (IP-add2) SB:- (IP-add1)

 

1- On MC-1 configure AP-group-1 with LMS= IP-add1

2- On MC-1 configure AP-group-1 with LMS-backup= IP-add2

3- On MC-1 configure AP-group-2 with LMS= IP-add2

4- On MC-1 configure AP-group-2 with LMS-backup= IP-add1

5- On MC-2 configure AP-group-1 with LMS= IP-add2

6- On MC-2 configure AP-group-1 with LMS-backup= IP-add1

7- On MC-2 configure AP-group-2 with LMS= IP-add1

8- On MC-2 configure AP-group-2 with LMS-backup= IP-add2

 

the tricky point here is that because this is a layer-2, AP using APD can connect to any of the two MC therefore, you have to find to which MC the AP registered with and assign it to the correct AP-group then MC will sync!

When single MMC goes down AP associated with it will shift to the second MMC.

 

I do not know if this will happen; therefore I put it here to have confirmation and more information if this will work and that MCs will sync APs assignment on Ap-groups. 

 

 <Here is what you do:

 

Configure two controllers in a Master/Backup master configuration.  This requires a VRRP to be configured.  Make sure that the "aruba-master" dns address points to the ip address of the VRRP.  Also make sure that in the AP-Group that your APs are in, the LMS-IP points to the VRRP.  Here is a dry runthrough:

 

If your APs boot and do not share a VLAN with either controller, they will discover the controller through the dns "aruba-master" a-record and attempt to contact the VRRP address.  If the first controller fails, the second one will take over in two seconds and the AP should be connected back in about 10 seconds.

 

If your APs boot and DO share a vlan with either controller, either controller will respond to a layer-2 ADP discovery from the AP with its literal ip address.  The AP will contact either controller and when the AP presents its ap-group to the controller, it will respond with the LMS-IP, which will be the VRRP.  The AP will establish a connection on that high availability address and the scenario is just like the one above, if the controller fails.


 


 



Colin Joseph
Aruba Customer Engineering

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

Frequent Contributor II
Posts: 135
Registered: ‎07-06-2012

Re: Master/Master (active-active) using VRRP and LMS

Hi Cjoseph,

 

I get your point, just I need to understand something. in ARUBA controller there is a default AP group which all AP will be connected to at the inisial stage, then Admin can re-assign the AP connected to the default AP group to an other AP groups. ARUBA recommends that the default AP group be isolated in case if a rouge AP connected to the network. However, if I have two Master/Master in layer 2 and I have two APs using ADP to register with the MC.  The AP will contact either controller and when the AP presents its ap-group ~ this ap-group will be the default; therefore, APs will not establish a connection on that VRRP high availability address, because the default ap-group should not have VRRP IP address in the LMS otherwise rouge device might be used. Does this mean that I have to connect to both MC (because some AP will connect to MC1 and others to MC2) and find the registered AP and assign them to the new AP Group which will have the VRRP IP in the LMS ? 

 

- can I take the AP mac address and assign them to the AP Group without waiting them to register ?

 

- if AP registered in different MCs, and then I logged in both MC and assigned the APs to the new AP-group will both MCs syncronize the APs assignment with AP-groups, therefore, next time even if APs rebooted and registered with the other MC they will get into the new AP-group with any intervention ?

 

Guru Elite
Posts: 20,990
Registered: ‎03-29-2007

Re: Master/Master (active-active) using VRRP and LMS

if you have two master controllers connected layer 2, they should be in a master/backup master relationship so that everything is synchronized.  This will fix everything. There is no benefit to have 2 masters layer2 that are NOT in a master/backup master relationship.

 

You cannot assign the AP and AP group ahead of time, no.  Once the ap comes up, change its ap-group.  If you have a master/backup master relationship, the next time the ap comes up, it should be in the right group and work.

 

 

 

 

 



Colin Joseph
Aruba Customer Engineering

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

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