Administrator Guide

745 | Remote Access Points Dell Networking W-Series ArubaOS 6.4.x| User Guide
vendor documentation for your server. It is recommended to use a maximum of 8 IP addresses to resolve a
controller name.
If the remote AP gets multiple IP addresses responding to a host name lookup, the remote AP can use one of
them to establish a connection to the controller. For more detailed information, see the next section Backup
Controller List on page 745.
Specifying the name also lets you move or change remote AP concentrators without reprovisioning your APs.
For example, in a DNS load-balancing model, the host name resolves to a different IP address depending on
the location of the user. This allows the remote AP to contact the controller to which it is geographically closest.
The DNS setting is part of provisioning the AP. The easiest way to provision an AP is to use the Provisioning
page in the WebUI. These instructions assume you are only modifying the controller information in the Master
Discovery section of the Provision page.
Reprovisioning the AP causes it to automatically reboot.
In the WebUI
1. Navigate to the Configuration > Wireless > AP Installation > Provisioning page. Select the remote AP
and click Provision.
2. Under Master Discovery enter the master DNS name of the controller.
3. Click Apply and Reboot.
For more information, see Provision the AP on page 726.
Backup Controller List
Using DNS, the remote AP receives multiple IP addresses in response to a host name lookup. Known as the
backup controller list, remote APs go through this list to associate with a controller. If the primary controller is
unavailable or does not respond, the remote AP continues through the list until it finds an available controller.
This provides redundancy and failover protection.
The remote AP loses the IP address information received through DNS when it terminates and receives the
system profile configuration from the controller. If the remote AP loses connectivity on the IPSec tunnel to the
controller, the RAP fails over from the primary controller to the backup controller. For this scenario, add the IP
address of the backup controller in the backup LMS and the IP address of the primary controller in the LMS
field of the ap-system profile. Network connectivity is lost during this time. As described in the section
Configuring Remote AP Failback on page 746, you can also configure a remote AP to revert back to the primary
controller when it becomes available. To complete this scenario, you must also configure the LMS IP address
and the backup LMS IP address.
For example, assume you have two data centers, data center 1 and data center 2, and each data center has one
master controller in the DMZ. You can provision the remote APs to use the controller in data center 1 as the
primary controller, and the controller in data center 2 as the backup controller. If the remote AP loses
connectivity to the primary, it will attempt to establish connectivity to the backup. You define the LMS
parameters in the AP system profile.