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Cisco 5700 Series Wireless LAN Controllers

CT5760 High Availability AP SSO Deployment Guide, Cisco IOS XE Release 3.3

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Table of Contents

CT5760 High Availability AP SSO Deployment Guide, Cisco IOS XE Release 3.3

Introduction

CT5760 Controller

5760 Access Point Stateful Switch Over (AP SSO) Overview

StackWise-480 Connectivity for HA

Verifying Stack Cable Connectivity

Monitoring the HA Pair

Accessing Standby WLC Console

CT5760 WLC Active and Standby Election Process

Setting the Switch Priority Value

Best Practices for HA Pairing Process

Configuring EtherChannels (LAG)

Provisioning CT5760 for HA (Optional)

State Transition for AP SSO

Verifying HA AP SSO

Verifying Redundancy States (CLI)

Verifying AP SSO State Sync

Viewing Switchover States (GUI)

Viewing Switchover History (GUI)

AP SSO Failover Process

Port Level Redundancy

System Level Redundancy

After a Switchover

Upgrading an HA Pair

AP SSO Hybrid Deployment with N+1 HA Topology

Licensing for HA with CT5760

AP SSO and 5760 HA-SKU

Feature Intersection with AP SSO

CT5760 High Availability AP SSO Deployment Guide, Cisco IOS XE Release 3.3

Last Updated: November, 2013

Release: CT 5760 High Availability AP SSO Deployment Guide, Cisco IOS XE Release 3.3

Introduction

This document introduces the Access Point Stateful Switch Over redundancy model for High Availability (HA) with CT5760 controllers using the StackWise-480 technology. HA in Cisco 5700 Series Wireless Controller is enabled using Cisco StackWise-480 technology. This deployment guide applies only to the Converged Access CT5760 Wireless LAN Controller. For more information on the CT5760 please refer to CT5760 Controller Deployment Guide.

CT5760 Controller

CT5760 is an innovative UADP ASIC based wireless controller deployed as a centralized controller in the next generation unified wireless architecture. CT5760 controllers are specifically designed to function as Unified model central wireless controllers. They also support the newer Mobility functionality with Converged Access switches in the wireless architecture.

Figure 1 Cisco WLC 5760

CT5760 is an extensible and high performing wireless controller, which can scale up to 1000 access points and 12000 clients. The controller has 6 - 10 Gbps data ports.

As a component of the Cisco Unified Wireless Network, the CT5760 series works in conjunction with Cisco Aironet access points, the Cisco Prime infrastructure, and the Cisco Mobility Services Engine to support business-critical wireless data, voice, and video applications.

5760 Access Point Stateful Switch Over (AP SSO) Overview

IOS XE 3.3 SE release for Cisco 5700 Series Wireless Controller introduces 1:1 Active-Standby redundancy model for HA with the CT5760 controllers using the StackWise-480 technology. HA in Cisco 5700 Series Wireless Controller is enabled using Cisco StackWise-480 technology. StackWise-480 identifies active and standby members in the stack as per the Cisco IOS Software SSO technology. All the control plane activities are centralized and synchronized between the active and standby units. The Active Controller centrally manages all the control and management communication. The network control data traffic is transparently switched from the standby unit to the active unit for centralized processing. The 12 ports of the CT5760 HA redundant pair can be connected to the infrastructure network either through a single switch or two switches.

Bulk and Incremental configuration is synced between the two controllers at run-time and both controllers share the same IP address on the management interface. The CAPWAP state of the Access Points that are in Run State is also synched from the active WLC to the Hot-Standby WLC allowing the Access Points to be state-fully switched over when the Active WLC fails. The APs do not go to the Discovery state when Active WLC fails, and Standby WLC takes over as the Active WLC to serve the network.

There is no preempt functionality with SSO meaning that when the previous Active WLC resumes operation, it will not take back the role as an Active WLC but will negotiate its state with the current Active WLC and transition to the Hot-Standby state. The Active and Standby election process is an automated election process that occurs as part of the SSO StackWise technology and will be explained later in the document.

HA with AP SSO is supported in Cisco 5700 Series Wireless Controllers. IOS XE 3.3 release only supports AP SSO i.e. APs will not disconnect and continue to be associated to the controller after a switchover. However, all clients will be de-authenticated and forced to rejoin new the Active WLC because Client SSO is not supported with this release.

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.

The StackWise-480 Cable is shown below and is available in lengths of 50 cm, 1 m, and 3 m.

Figure 2 StackWise-480 Cable

 

Figure 3 Stack Cable Part Numbers

 

Each CT5760 WLC has two Stack Ports and it is recommended to connect the Stack Cables in a full-ring setup as shown below for stack cable redundancy.

Figure 4 CT5760 Controllers Connected in Full-ring Setup

 

The StackWise-480 cable needs to be plugged into the Stack Port as shown below with the Cisco Logo facing upward.

Figure 5 Stack Cable Plugged into Stack Port on CT5760 WLC

 


Note Customers who buy AIR-CT5760-HA with 3.3 will also be given an option to buy stack cables.


Verifying Stack Cable Connectivity

The command show switch stack-ports summary can be used to verify the connectivity of the Stack Cables.

Figure 6 show switch stack-ports summary Output

 

Verify that the:

  • Port Status is OK i.e. The cable is detected and connected neighbor is up.
  • Link OK is Yes i.e. The stack cable connected.
  • Link Active is Yes i.e. The neighbor is detected. The Port can send traffic over this link.

The table provides details on what the various fields refer to.

Table 1 Description of show switch stack-ports summary Output

Parameter
Description

Switch#/Port#

Member number and its stack port number.

Stack Port Status

Status of the stack port.

  • Absent—No cable is detected on the stack port.
  • Down—A cable is detected, but either no connected neighbor is up or the stack port is disabled.
  • OK—A cable is detected and the connected neighbor is up.

Neighbor

Switch number of the active member at the other end of the stack cable.

Cable Length

Valid lengths are 50 cm, 1 m, or 3 m. If the CT5760 WLC cannot detect the cable length, the value is no cable. The cable might not be connected or the link might be unreliable.

Link OK

Whether the stack cable is connected and functional. There may or may not be a neighbor connected on the other end. The link partner is a stack port on a neighbor switch.

  • No—There is no stack cable connected to this port or the stack cable is not functional.
  • Yes—There is a functional stack cable connected to this port.

Link Active

Whether a neighbor is connected on the other end of the stack cable.

  • No—No neighbor is detected on the other end. The port cannot send traffic over this link.
  • Yes—A neighbor is detected on the other end. The port can send traffic over this link.

Sync OK

Whether the link partner sends valid protocol

messages to the stack port.

  • No—The link partner does not send valid protocol messages to the stack port.
  • Yes—The link partner sends valid protocol messages to the port.

# Changes to LinkOK

The relative stability of the link. If a large number of changes occur in a short period of time, link flapping can occur.

In Loopback

Whether a stack cable is attached to a stack port on the member.

  • No—At least one stack port on the member has an attached stack cable.
  • Yes—None of the stack ports on the member has an attached stack cable.

Monitoring the HA Pair

The command show switch displays summary information about the HA Pair, including the MAC address, role, switch priority, and current state of each CT5760 WLC in the redundant HA pair.

Figure 7 show switch Output

 

By default, the Local MAC Address of the HA Pair is the MAC address of the current Active Controller. When a switchover occurs, the MAC address changes to the MAC address of the new Active Controller.

However, the Persistent MAC Address feature can be used to set a time delay before the MAC address changes.

Figure 8 MAC Persistency Feature Command

 

  • Enter the command without a value or with a value of 0 to continue using the MAC Address of the current active controller indefinitely.
  • Enter a time-value from 1 to 60 minutes to configure the time period before the redundant unit MAC Address changes to the new Active Controller. The MAC address of the previous active controller is used until the configured time period expires.

Accessing Standby WLC Console

The active controller can be accessed through a console connection, Telnet, an SSH, or a Web Browser by using the Management IP address. To access the IOS console of the standby WLC, use the session standby ios privileged EXEC command from the active CT5760 after executing the following commands from the config mode.

conf t

service internal

redundancy

main-cpu

standby console enable

end

session standby ios

The prompt on the Standby console is appended with “-stby” to reflect the Standby WLC console as shown below.

Figure 9 Standby Console and show switch for Standby WLC

 

The show switch command points to the current CT5760 WLC on the console using the (*) symbol against the switch number as shown above.

CT5760 WLC Active and Standby Election Process

An active CT5760 WLC retains its role as an Active Controller unless one of the following events occur:

  • The CT5760 WLC HA pair is reset.
  • The active CT5760 WLC is removed from the HA pair.
  • The active CT5760 WLC is reset or powered off.
  • The active CT5760 WLC fails.
  • Powered-on standalone CT5760 WLC is merged with the current Active CT5760 WLC.

The active WLC CT5760 is elected or re-elected based on one of these factors and in the order listed below:

1. The CT5760 that is currently the active CT5760.

2. The CT5760 WLC with the highest stack member priority value.


Note We recommend assigning the highest priority value to the WLC 5760 you prefer to be the active controller. This ensures that the controller is re-elected as active controller if a re-election occurs.


Setting the Switch Priority Value

switch stack-member-number priority new-priority-number

\\ Specifies the stack member number and the new priority for the stack member. The stack member number range is 1 to 9. The priority value range is 1 to 15.

Example

5760# switch 2 priority 2

You can display the current priority value by using the show switch user EXEC command. The new priority value takes effect immediately but does not affect the current Active Controller. The new priority value helps determine which controller is elected as the new Active Controller when the current active CT5760 WLC or HA redundant pair reloads.

3. The CT5760 with the shortest start-up time.

4. The CT5760 with the lowest MAC Address.

The ACTV LED on the switch can be used to identify the current Active Controller.

Best Practices for HA Pairing Process

  • Adding a powered-on CT5760 WLC (merging) to an existing Active Controller causes both WLCs to reload and elect a new active controller from among themselves.
  • Make sure that the controller to be paired is powered down before connecting it to the existing Active Controller by using Stack Cables. Once the Stack Cables are connected, power on the new controller. The newly introduced controller will take up its role as a Hot-Standby controller because an Active Controller already exists.
  • Similarly, removing a powered-on WLC causes both WLCs to reload. Power down the controller that needs to be removed before disconnecting the Stack Cables to avoid this.

Configuring EtherChannels (LAG)

The LAG, or an EtherChannel, bundles all the existing ports in both the standby and active units into a single logical port to provide an aggregate bandwidth of 60 Gbps. The creation of an EtherChannel enables protection against port failures and provides port level redundancy. The EtherChannels or LAGs created are used for link redundancy to ensure HA of Access Points. Multiple LAGs can be configured on the CT5760 WLC.

1. Connect two CT5760 WLCs that are in powered down state using the Stack Cable.

2. Power up and perform a boot on both controllers simultaneously or power and boot one controller.

3. The controllers boot up successfully and form a HA pair.

4. Configure EtherChannel or LAG on the units.

5. Use the show etherchannel summary command to view the status of the configured EtherChannel.

6. On successful configuration, all the specified ports will be bundled in a single channel and listed in the command output of show etherchannel summary .

7. Execute the show ap uptime command to verify the connected Access Points.

Link Aggregation Control Protocol (LACP) can be configured by using the l acp port-priority number command.

Sample output of show etherchannel summary when LACP is configured is shown:

5760# show etherchannel summary

Flags: D - down P - bundled in port-channel

I - stand-alone s - suspended

H - Hot-standby (LACP only)

R - Layer3 S - Layer2

U - in use f - failed to allocate aggregator

M - not in use, minimum links not met

u - unsuitable for bundling

w - waiting to be aggregated

d - default port

Number of channel-groups in use: 1

Number of aggregators: 1

 

Provisioning CT5760 for HA (Optional)

The offline configuration feature can be used to provision (to supply a configuration to) a new CT5760 WLC before it is paired with the Active Controller. You can configure the stack member number, the switch type, and the interfaces associated with a WLC that is not currently part of the HA redundant pair. The configuration that is created on the active WLC is called the provisioned configuration. The WLC that is paired with the active controller and that receives this configuration is called the provisioned switch.

The provisioned configuration is manually created through the switch stack-member-number provision type global configuration command. The stack-member-number and type on the provisioned CT5760 must match the stack member number and type that was created for the new controller before it is paired with the active controller.

When you configure the interfaces associated with a provisioned CT5760 WLC, the active controller accepts the configuration and the information appears in the running configuration. However, because the second controller is not active, any configuration on the interface is not operational and the interface associated with the provisioned unit does not appear in the display of the specific feature. For example, VLAN configuration information associated with a provisioned WLC does not appear in the show vlan user EXEC command output. The provisioned configuration is retained in the running configuration whether or not the provisioned WLC is part of the HA pair. You can save the provisioned configuration to the startup configuration file by entering the copy running-config startup-config privileged EXEC command.

The show running-config command output shows the interfaces associated with the provisioned WLC.

5760(config)# switch 2 provision air-ct5760-6

5760(config)# end

\\Where 2 = switch number of new CT5760, air-ct5760-6 = SKU of CT5760

5760# show running-config | include switch 2

!

interface GigabitEthernet2/0/1

!

interface GigabitEthernet2/0/2

!

interface GigabitEthernet2/0/3

<output truncated>

State Transition for AP SSO

Figure 10 Active WLC in Simplex Mode

 

 

Figure 11 Standby Insertion for HA Pairing

 

 

Figure 12 HA Sync in Progress

 

Figure 13 Terminal State for SSO

 

Figure 14 CT5760 WLCs in Duplex SSO Mode

Verifying HA AP SSO

Verifying Redundancy States (CLI)

An Access Point Stateful Switch Over (AP SSO) implies that all the Access Point sessions are switched over state-fully and Access Points continue to operate in a network with no loss of sessions, providing improved network availability and reducing service downtime. The Active Controller in the redundant pair is equipped to support 1000 Access Points and 12000 clients.

Once a redundancy pair is formed while in a stack, HA is enabled, which means that Access Points continue to remain connected during an active-to-standby switchover.

The command show redundancy states displays all the redundancy states of the active and standby controllers.

Manual Switchover Action (Manual Swact) i.e. the command redundancy force-switchover cannot be executed on the Standby WLC and is enabled only on the Active Controller.

Figure 15 Redundancy State for Active WLC

 

Figure 16 Redundancy State for Standby WLC

The command show redundancy displays the redundant system and the current processor information. The redundant system information includes the system uptime, standby failures, switchover reason, hardware mode, and configured and operating redundancy mode. The current processor information displayed includes the image version, active location, software state, BOOT variable, configuration register value, and uptime in the current state, and so on. The Peer Processor information is only available from the Active Controller.

Figure 17 show redundancy on Active Controller

 

Figure 18 show redundancy on Standby Controller

 

Verifying AP SSO State Sync

AP CAPWAP state information is synced to the standby controller. AP uptime and association time can be verified using the command show ap summary and show ap uptime on the Active and Standby Controllers.

Figure 19 AP Summary and Uptime on Active WLC

 

Figure 20 AP Summary and Uptime on Standby WLC

 

Viewing Switchover States (GUI)

Navigate to Monitor > Controller > Redundancy > States on the controller Web UI. The Redundancy States page is displayed:

Figure 21 Redundancy States Display on GUI

 

The description of the parameters in the output is given below:

Table 2 Redundancy States Display Parameters

Parameter
Description

My State

Shows the state of the active CPU controller module. Values are as follows:

  • Active
  • Standby HOT
  • Disable

Peer State

Displays the state of the peer (or standby) CPU controller module. Values are as follows:

  • Standby HOT
  • Disable

Mode

Displays the current state of the redundancy peer. Values are as follows:

  • Simplex— Single CPU controller module.
  • Duplex— Two CPU controller modules.

Unit ID

Displays the unit ID of the CPU controller module.

Redundancy Mode (Operational)

Displays the current operational redundancy mode supported on the unit.

Redundancy Mode (Configured)

Displays the current configured redundancy mode supported on the unit.

Redundancy State

Displays the current functioning redundancy state of the unit. Values are as follows:

  • SSO
  • Not Redundant

Manual Swact

Displays whether manual switchovers have been enabled.

Communications

Displays whether communications are up or down between the two controllers.

Viewing Switchover History (GUI)

Navigate to Monitor > Controller > Redundancy > Switch Over History on the controller Web UI.

The Redundancy Switch Over History page is displayed:

Figure 22 Switch Over History Page

 

The description for the following parameters are displayed in the table below:

Table 3 Switch Over History Parameter Description

Parameter
Description

Index

Displays the index number of the redundant unit.

Previous Active

Displays the controller that was active prior to switchover.

Current Active

Displays the controller that is currently active.

Switch Over Time

Displays the system time when the switchover occurred.

Switch Over Reason

Displays the cause of the switchover.

AP SSO Failover Process

Port Level Redundancy

The 12 ports of CT5760 WLC can be connected to the infrastructure network either through a single switch or through two switches. In either case, the ports of CT5760 WLC are configured into LAG bundles. Failing of ports connected to neighbor switches does not induce a system switchover and it only affects bandwidth when less than 6 ports are active. However, system switchover can occur due to various reasons identified below.

System Level Redundancy

Process Failure Switchover

This type of switch over occurs when any of the key processes running on the Active unit fails or crashes. Examples of this are HA Manager, WCM, Stack Manager, FED, FFM, and so on. Upon such a failure, the Active unit reloads and the hot Standby takes over and becomes the new Active unit. When the failed system boots up, it will transition to Hot-Standby state. If the Standby unit is not yet in Hot Standby State, both units are reloaded and there will be no AP SSO. A process failure on the standby (hot or not) will cause it to reload.

Power-fail Switchover

This switchover from the Active to Standby unit is caused due to power failure of the current Active unit. The current Standby unit becomes the new Active unit and when the failed system boots up, it will transition to Hot-Standby state.

Manual Switchover

The HA feature is enabled by default when CT5760 WLCs are connected using the stack cable and the Cisco StackWise-480 technology is enabled. You cannot disable it; however, you can initiate a manual graceful switchover using the command line interface. This is a user initiated forced switchover between the Active and Standby unit. The current Standby unit becomes the new Active unit and when the failed system boots up, it will transition to Hot-Standby state. To perform a manual switchover, execute the redundancy force-switchover command. This command initiates a graceful switchover from the active to the standby controller. The active controller reloads and the standby takes over as the New Active controller.

Figure 23 Manual Switchover Command

 

The table below gives an estimate of the time metrics involved in the failover process:

Table 4 APSSO Failover Time Metrics

Metrics
Time

Failure Detection

In the order of 50 ms.

Reconciliation Time (Standby becoming Active)

In the order of 1020 ms.

*First Client rejoin time

Dot1x client: 64s; open client: 16s.

*All clients (12K) rejoin time

Dot1x: 228s; open clients: 153s.

*with 12K clients prior to switchover

After a Switchover

On successful switchover of the standby CT5760 WLC as active, all access points connected to the previously active WLC must remain connected to the new Active controller.

Clients must be de-authenticated upon a switchover. This can be verified by executing the commands:

  • show ap uptime : Verifies that the uptime of the access point after the switchover is not reset.
  • show wireless client summary: Displays the clients connected to the new Active controller.

Upgrading an HA Pair

Prior to IOS XE Release 3.3, AP SSO was not supported on CT5760 WLCs. Upgrade individual controllers to image version 3.3 before pairing them for HA using the guidelines explained in the Best Practices for HA Pairing Process section.

Upgrade of an HA Pair to image versions after IOS XE Release 3.3 can be achieved by following the steps listed below:

1. Copy image to flash: for Active CT5760 WLC.

2. Make sure the BOOT variable is set to reflect installed mode boot

boot system switch all flash:packages.conf

3. Run the software install file flash:<image.bin> command pointing to the new image on the flash to upgrade the HA Pair without having to upgrade controllers individually.

  • The Auto-Upgrade feature is not supported in this release.
  • Pairing of CT5760 WLCs running different software versions is not supported.
  • Recommendation is to upgrade both Active and Standby controllers simultaneously as explained above.

AP SSO Hybrid Deployment with N+1 HA Topology

Figure 24 AP SSO Hybrid Deployment with N+1 Topology

 

A hybrid topology of AP SSO redundant pair and N+1 primary, secondary and tertiary model is supported as shown above. The secondary controller at the DR site can be a CT5760 or a CUWN controller running New Mobility. Access points failing back from converged access CT5760 WLC to CUWN controllers will re-download the code before joining the CUWN WLC.

Licensing for HA with CT5760

In a HA redundant pair, the AP count is combined from license counts on both controllers. The Active controller will display all AP licenses broken down per controller. The total number of APs that can be supported by the CT5760 WLC HA pair is 1000.

When CT5760 WLCs are paired together to form a HA pair, the cumulative AP count may exceed 1000. However, the WCM module on the controller does the gate keeping of not allowing more than 1000 APs on the redundant HA pair. A warning message on the console indicates to the user that the cumulative AP count has exceeded the maximum AP count of 1000.

In the remove case, the in-use AP count may exceed available AP count licenses on the active controller. If the total number of APs connected exceeds the available AP count in the HA pair, syslog and warning messages are displayed that those APs would be disconnected on AP or Stack reboot. The above can happen if a deleted controller takes away the AP count with it or by configuration, where the customer reduces number of adder licenses. In general, when a controller is removed from the HA pair, it takes the previously installed AP count with it. However, the active controller will continue to support the AP count of that lost controller in order not to interrupt the service, but upon either a controller or an AP reboot, some APs will not be able to join back and the APs that can join the controller will fall back to the AP count available on the active controller, i.e., the AP count licenses originally on that controller.

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.

The following table shows the examples of pairing controllers and their effects on the licenses for the APs.

Table 5 Examples of Controller Pairing and Licenses

Controllers
Pairing Effect and AP Licenses

AIR-CT5760-HA-K9 SKU with

Standby: AIR-CT5760-HA-K9 SKU

Both the units are active and the standby controller has the HA SKU. Pairing is not allowed. There are no licenses for an AP.

AIR-CT5760-<apcount>-K9 SKU with

Standby: AIR-CT5760-HA-K9

The licenses for an AP are limited as per the AP count on the active controller.

AIR-CT5760-HA-K9 SKU with

Standby: AIR-CT5760-<apcount>-K9

On AIR-CT5760-500-K9, there are 1000 APs with a Syslog warning–AP License usage exceeded by 500. The additional APs would disconnect after stack reboot or AP reboot.

AIR-CT5760-<apcount>-K9 SKU with

Standby: AIR-CT5760-<apcount>-K9

Active controller has licenses for 500 APs. The standby controller has licenses for 250 APs. In total there are licenses for 750 APs. The total AP count is limited to 1000.

AIR-CT5760-<apcount>-K9 SKU with

AIR-CT5760-<apcount>-K9

The first controller with Release 3.3 build and second controller with EX1/CCO. Both controllers need to have the same version of code on them for pairing. If not, there is a mismatch.

AIR-CT5760-<apcount>-K9 SKU [DTLS image] with AIR-CT5760-<apcount>-K9

There are two possibilities–In case of LDPE with LDPE, pairing is done. For LDPE with non-LDPE, there is a mismatch.

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.