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Master Backup replicated configuration

I have configured the Master backup usign HA and VRRP, but some configuration is not replicated, like DHCP and interfaces VLANs. I checked docummentation and this needed to be configured on the backup master controller, but, I'm not sure if when configuring interfaces VLANs can I put the same IP as the Master?, should the Interfaces VLAN's IPs be different?

Guru Elite

Re: Master Backup replicated configuration

The VLAN and ip configuration is not replicated, because it is specific to each controller.  Routing, what VLAN is on what port, what ports are trunked are individual to each controller and are configured as such.  Each controller would need its own management ip address and optionally a unique ip address on each VLAN.  Both controllers needs to be on the network at the same time, so the only thing they really share is the VRRP ip address...

 



Colin Joseph
Aruba Customer Engineering

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

Re: Master Backup replicated configuration

Hi, Sorry, I'm not totally sure about Interface VLANs, I have routing on one of the Interfaces VLAN, but I want to maintain the same IP on the Backup-Master WLC. Is that possible according to this configuration?

Guru Elite

Re: Master Backup replicated configuration

When you say "routing", do you mean that the default gateway of your client is that of the controller?

 



Colin Joseph
Aruba Customer Engineering

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

Re: Master Backup replicated configuration

 

I have 3 interfaces vlans in the Master Controller, to be able to use the WLC as a DHCP Server. Can I duplicate this on the Backup-Master Controller, or they should be different?.

Guru Elite

Re: Master Backup replicated configuration

If you are using the controller as a DHCP server, you will need to use the "split scope" strategy, where you serve the first half of the scope on one controller and the second half on another.  Why?  Because if the first controller goes down, there needs to still be a dhcp server to provide addresses.  If you duplicate the same scope on both controllers, clients will end up getting duplicate dhcp addresses, which is a disaster.  Even though a backup master cannot terminate access points, it will still answer to dhcp requests if a dhcp server is defined.   Long story short, use an external DHCP server to avoid that issue and make the default gateway an external router, so that you do not have state issues with clients that fail over.  Using external routing sidesteps the issue of your clients having the default gateway of the first controller, but not being able to go anywhere upon failover.

 

I hope that helps...



Colin Joseph
Aruba Customer Engineering

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

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