@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>
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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.