Users Guide
Dell Networking W-Series ArubaOS 6.4.x| User Guide Increasing Network Uptime Through Redundancy and VRRP | 661
Chapter 24
Increasing Network Uptime Through Redundancy and VRRP
A single controller at the core of a network can represent a single point of failure. ArubaOS high availability and
Virtual Router Redundancy Protocol (VRRP) redundancy features allow network administrators to significantly
reduce network downtime and client traffic disruption during network upgrades or unexpected failures.
High Availability
When you enable the High Availability WLAN redundancy solution, campus APs that lose contact with their
active controller do not need to re-bootstrap when they failover to the standby controller,significantly
reducing AP downtime. APs using the High Availability features regularly communicate with the standby
controller so the controller has a light workload to process in the event of an AP failover. This results in very
rapid failover times and a shorter client reconnect period. Therefore, High Availability is usually preferable to
other redundancy solutions (like a backup-LMS) that can put a heavy load on the backup controllerduring
failover, which results in slower failover performance.
High Availability supports failover for campus APs using tunnel, decrypt-tunnel, or bridge forwarding modes. It
does not support failover for remote APs.
AP Fast Failover on bridge forwarding mode virtual AP is supported on the W-7000 and W-7200 Series controllersonly.
Pre-Deployment Information
For information to help you plan your high availability solution, refer to the following sections of this
document:
l High Availability Deployment Models on page 662
l High Availability Extended Controller Capacity on page 665
l Client State Synchronization on page 664
l High Availability Inter-Controller Heartbeats on page 665
Configuration Procedures
For more information on configuring the high availability feature, refer to the following sections of this
document:
l Configuring High Availability on page 667
l Migrating from VRRP or Backup-LMS Redundancy on page 669
VRRP-Based Redundancy
The Virtual Router Redundancy Protocol (VRRP) is used to create various redundancy solutions, including pairs
of local controllers acting in an active-active mode or a hot-standby mode, or a master controller backing up a
set of local controllers. The master controller owns the configured virtual IP address for the VRRP instance.
When the master controller becomes unavailable, a backup controller steps in as the master and takes
ownership of the virtual IP address. All network elements (APs and other controllers) can be configured to
access the virtual IP address, thereby providing a transparent redundant solution to your network.