Wireless Access

Hi,

I have two 7240's in a Master-Standby setup with VRRP, where all AP's terminate on the Master controller. The other controller is hot standby. They are both in the same subnet.

If I want to implement Fast Failover, what should be the values of the LMS & backup-LMS IP?
The Aruba bootcamp book is saying to enter the VIP, some forums tell me to enter only the LMS-IP and leave the backup-IP field blank. I've also found an Aruba page, telling me the LMS fields are "optional".

Please see "Migrating from VRRP Redundancy" here:  http://www.arubanetworks.com/techdocs/ArubaOS_64x_WebHelp/Web_Help_Index.htm#ArubaFrameStyles/VRRP/HighAvMigration.htm%3FTocPath%3DVirtual%2520Router%2520Redundancy%2520Protocol%2520(VRRP)%7C_____6

Thanks a lot, didn't came across that page yet. I found this page, but I notice that this is probably for AOS 6.3:

http://www.arubanetworks.com/techdocs/ArubaOS_63_Web_Help/Content/ArubaFrameStyles/VRRP/HighAvFastFailover.htm

If I understand correctly, to setup Fast Failover in a VRRP based setup, set the mode to "dual" is a must?

Yes

EDIT:  No.

EDIT:  YES.

Explanation:

Back in 6.3.x, we could not support HA and Master Redundancy, with DUAL.   In 6.4 We could, that is why the instructions are different.  I apologize for the confusion. 

Thanks again. One additional question.

I have preempt configured on the VRRP groups, as well on the HA group.

Is it best practise to enable LMS preemption in that case?

Can't seem to find these steps in the link you provided, only thing I find is setting it up as "dual":

That Active/standby mode came from the 6.3 document.

this is from the link you provided:

Migrating from VRRP Redundancy

Perform the following steps to migrate from VRRP to High-Availability redundancy:

(host) (AP system profile) #no lms-ip

(host) (AP system profile) #lms-ip <ipaddress>

(host) (AP system profile) #bkup-lms-ip <ipaddress>

(host) (config) #ha group-profile grp1

(host) (HA group information "grp1"): controller <ipaddress> role dual

(host) (HA group information "grp1"): controller <ipaddress> role dual

The answer is Yes.

Explanation:

Back in 6.3.x, we could not support HA and Master Redundancy, with DUAL.   In 6.4 We can, that is why the instructions are different.  I apologize for the confusion. 

All clear now! thanks a lot.

Currently I'm doing preemption on the HA. Should I then also enable LMS-preemption?

Yes, you should.

Hi Joseph,

I'm been thinking more about the setup I have now, and I'm wondering:

If the controllers are in a L3 VRRP setup (Active/Standby), is HA: Fast Failover still necessary.

- If the active controller fails, VRRP will switch over to the Standby controller

- All AP's will still terminate on the VRRP VIP address.

- HA won't have any effect in this scenario.

So I'm starting to think I don't need HA Fast Failover in my setup?

You can use either one, in that scenario.

Thanks for the reply.

When you say either one, do you mean use VRRP - OR - use HA Fast Failover as failover mechanism.

I'm trying to figure out if there's an advantage in running both simultaniously?

Yes.

There is no significant advantage to running them simultaneously if you are using master/backup master (standby) and you are already pointing access points to the VRRP.

Well, Configuring APFF in addition to VRRP on Master Active/Standby will help in the situation where you have many APs and you need them to smoothly moving from the Active to Standby at the time of failure. With APFF and HA the APs will create two IPSec/GRE tunnels to the Active and Standby controllers that help the APs to imidiatly switch to the standby controller (Less delay time).

The standby controller will not be able to service clients until it has control of the VRRP.  If the access points fail over before the VRRP is switched, the clients on those access points will not be able to do anything.

It is best to just deploy APS pointing to a VRRP between master/standby.  For any other relationship, fast failover will work just fine.