Cisco Cisco 5520 Wireless Controller Referencia técnica
Cisco Systems, Inc.
www.cisco.com
www.cisco.com
High Availability (SSO) Deployment Guide
Last Updated: December, 2014
Introduction
This document provides information on the theory of operation and configuration for the Cisco Unified
Wireless LAN Controller (WLC) as it pertains to supporting stateful switchover of access points and
clients (AP and Client SSO).
Wireless LAN Controller (WLC) as it pertains to supporting stateful switchover of access points and
clients (AP and Client SSO).
The new High Availability (HA) feature (that is, AP SSO) set within the Cisco Unified Wireless Network
software release version 7.3 and 7.4 allows the access point (AP) to establish a CAPWAP tunnel with
the Active WLC and share a mirror copy of the AP database with the Standby WLC. The APs do not go
into the Discovery state when the Active WLC fails and the Standby WLC takes over the network as the
Active WLC.
software release version 7.3 and 7.4 allows the access point (AP) to establish a CAPWAP tunnel with
the Active WLC and share a mirror copy of the AP database with the Standby WLC. The APs do not go
into the Discovery state when the Active WLC fails and the Standby WLC takes over the network as the
Active WLC.
There is only one CAPWAP tunnel maintained at a time between the APs and the WLC that is in an
Active state. The overall goal for the addition of AP SSO support to the Cisco Unified Wireless LAN is
to reduce major downtime in wireless networks due to failure conditions that may occur due to box
failover or network failover.
Active state. The overall goal for the addition of AP SSO support to the Cisco Unified Wireless LAN is
to reduce major downtime in wireless networks due to failure conditions that may occur due to box
failover or network failover.
To support High Availability without impacting service, there needs to be support for seamless transition
of clients and APs from the active controller to the standby controller. Release 7.5 supports Client
Stateful Switch Over (Client SSO) in Wireless LAN controllers. Client SSO will be supported for clients
which have already completed the authentication and DHCP phase and have started passing traffic. With
Client SSO, a client's information is synced to the Standby WLC when the client associates to the WLC
or the client’s parameters change. Fully authenticated clients, i.e. the ones in Run state, are synced to the
Standby and thus, client re-association is avoided on switchover making the failover seamless for the
APs as well as for the clients, resulting in zero client service downtime and no SSID outage.
of clients and APs from the active controller to the standby controller. Release 7.5 supports Client
Stateful Switch Over (Client SSO) in Wireless LAN controllers. Client SSO will be supported for clients
which have already completed the authentication and DHCP phase and have started passing traffic. With
Client SSO, a client's information is synced to the Standby WLC when the client associates to the WLC
or the client’s parameters change. Fully authenticated clients, i.e. the ones in Run state, are synced to the
Standby and thus, client re-association is avoided on switchover making the failover seamless for the
APs as well as for the clients, resulting in zero client service downtime and no SSID outage.