CT5760 High Availability AP SSO Deployment Guide

StackWise-480 Connectivity for HA

A CT5760 HA Pair is a special case of a switch stack that can have up to two CT5760 controllers connected through their StackWise-480 ports. The stack members work together as a unified system

A third CT5760 cannot join the switch stack or HA pair. A switch stack always has one active controller and one standby controller. If the active controller becomes unavailable, the standby assumes the role of the active, and continues to the keep the stack operational.

The active controller controls the operation of the HA pair, and is the single point of stack-wide management. The term switch is loosely used in the document to refer to the CT5760 WLC for this reason.

StackWise-480 has a stack bandwidth of 480 Gbps and uses SSO to provide resiliency within the HA Pair. The Active CT5760 WLC creates and updates all the wireless information and constantly synchronizes that information with the standby controller.

If the active WLC fails, the standby WLC assumes the role of the active WLC and continues to the keep the HA Pair operational. Access Points continue to remain connected during an active-to-standby switchover.

AP SSO and 5760 HA-SKU

  • The 5760 HA-SKU provides support for up to 1000 APs when Active controller Fails over to HA-SKU unit.
  • The following notification is generated on the HA-SKU controller when a Standby non HA-SKU is lost:

“The current stack does not support the applied AP License Count. Reconnect a Catalyst 5760 SKU running valid AP License Count within 90 days.”

  • Two 5760 HA-SKU units cannot be connected to be paired in an SSO pair.
  • Licenses cannot be added to a 5760 HA-SKU unit.
  • The 5760 HA-SKU has a PID AIR-CT5760-HA-K9 to indicate that it is a HA-SKU unit.
  • A non HA-SKU 5760 controller cannot be converted to a HA-SKU by configuration.

Feature Intersection with AP SSO

  • Switchover during AP Pre-Image download causes the APs to start image download all over again from the new Active controller.
  • Rogue APs and clients are not synced to Standby and are re-learnt upon switchover.
  • Infrastructure MFP key is not synced to the Standby controller and is re-learnt upon switchover.
  • New Active controller re-learns the shun list from IPS and other MCs, and redistributes it to the MAs.
  • wIPS information is not synced to the Standby unit and is re-learnt upon switchover.
  • Clean Air detected Interferer devices are re-learnt after switchover.
  • Net Flow records are cleared upon switchover and collection starts fresh on the new Active controller.
  • Mobility paths and tunnels to the MO and other peer MCs are not disrupted upon switchover. However the Client state is cleaned up on the MO under which the HA pair exists and is re-learnt from the new Active controller when the client re-associates.
  • Roamed clients that have their data path going through the Mobility Tunnel Endpoint (MTE) “become Local” in case of L2 with Sticky Anchoring and L3 Roam. L2 Roamed Clients are not affected except when roaming occurs between CUWN and CA controllers.
  • RRM related configurations and the AP neighbor list in the Leader HA pair is synced to the Standby controller.
  • Upon Guest Anchor controller switchover, mobility tunnels stay active, APs remain connected, clients rejoin at MA or MC, and are anchored on the new Active controller.

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