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Frequent Contributor I

Two MDs: Pre-emption is not working.

Can anyone help to see why the pre-emption is not working?

1. AP connected to the master MD,

2. the master MD failed,  AP failed over to the backup MD.

3. AP stayed connecting with the backup MD and did not go to connect to the Master MD unless rebooting AP.

 

Thank you!

 

Here are config for two managed devices.

(OAW-4750XM-2) #show vrrp


Virtual Router 12:
Description mc-vrrp
Admin State UP, VR State MASTER
IP Address 172.16.0.241, MAC Address 00:00:5e:00:01:0c, vlan 1
Priority 110, Advertisement 1 sec, Preemption Enable Delay 30
Auth type PASSWORD, Auth data: ********
tracking is not enabled
(OAW-4750XM-2) #

 

(172.16.0.252) #show vrrp


Virtual Router 12:
Description mc-vrrp
Admin State UP, VR State BACKUP
IP Address 172.16.0.241, MAC Address 00:00:5e:00:01:0c, vlan 1
Priority 100, Advertisement 1 sec, Preemption Disable Delay 0
Auth type PASSWORD, Auth data: ********
tracking is not enabled
(172.16.0.252) #

 

 

Re: Two MDs: Pre-emption is not working.

What version of AOS are you running? Is there a Mobility Master?

 

How are the APs discovering the master controller IP? ADP, DNS, DHCP, or static?

 

To clarify your question, is VRRP pre-emption not working, or has the master for the virtual IP moved back to OAW-4750XM-2 and the APs have not moved with it?


Charlie Clemmer
Aruba Customer Engineering
Frequent Contributor I

Re: Two MDs: Pre-emption is not working.

Thank you for your help!

1. version: 8.3.0.0

2. there is a mobility master

3. AP discovers the controller by Static IP (VIP)

4. virtual IP moved back to OAW-4750XM-2 and the APs have not moved with it.

Best regards,

 

 

Re: Two MDs: Pre-emption is not working.

Are the two MDs part of a cluster? 


Charlie Clemmer
Aruba Customer Engineering
Frequent Contributor I

Re: Two MDs: Pre-emption is not working.

Yes, thanks!

Re: Two MDs: Pre-emption is not working.


@BCroll wrote:

Yes, thanks!


Because the two controllers are clustered, this makes sense.

 

The discovery methods (DNS/DHCP/Static/ADP/etc) are used to discover some/any node in the cluster. Once that node is contacted, the AP downloads the nodelist with all the IPs for controllers in the cluster. This nodelist contains the physical IPs, not virtual-IPs. The cluster leader also determines the APs anchor and standby anchor controller, and the AP builds tunnels to both.

 

In the case of clustering, the VIP from VRRP is used solely for discovering the cluster. AP tunnels do not use the VIP. The VIP adds robustness to prior discovery methods to ensure that as long as any controller in the cluster is active, APs will be able to discover the cluster.


Charlie Clemmer
Aruba Customer Engineering
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