Contents

1 Configuring dual-link backup· 1-1

About dual-link backup· 1-1

Restrictions and guidelines: Dual-link backup configuration· 1-1

Dual-link backup tasks at a glance· 1-2

Setting AP connection priority and specifying a backup AC· 1-2

Configuring master CAPWAP tunnel preemption· 1-2

Dual-link backup configuration examples· 1-3

Example: Configuring dual-link backup· 1-3

 

1 Configuring dual-link backup

About dual-link backup

Dual-link backup enables two ACs to back up each other to reduce risks of service interruption caused by single-AC failures.

With dual-link backup enabled, an AP establishes a master CAPWAP tunnel and a backup CAPWAP tunnel with the master AC and the backup AC, respectively. The master and backup ACs cannot detect each other's link state in real time. When the backup AC takes over traffic forwarding upon a master AC failure, temporary communication interruption occurs. When the failed master AC recovers, the master CAPWAP tunnel preemption feature determines the master CAPWAP tunnel based on the AP connection priority.

Dual-link backup is applicable to networks that are service continuity insensitive.

Figure1-1 Network diagram for dual-link backup

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Restrictions and guidelines: Dual-link backup configuration

For the dual-link backup feature to function correctly, configure auto AP or manual APs on the two ACs. The manual AP configuration must be identical on both ACs. For more information, see managing APs in AP and WT Management Configuration Guide.

You can configure APs by using the following methods:

·     Configure APs one by one in AP view.

·     Assign APs to an AP group and configure the AP group in AP group view.

·     Configure all APs in global configuration view.

For an AP, the settings made in these views for the same parameter take effect in descending order of AP view, AP group view, and global configuration view.

Dual-link backup tasks at a glance

To configure dual-link backup, perform the following tasks:

1.     Setting AP connection priority and specifying a backup AC

2.     (Optional.) Configuring master CAPWAP tunnel preemption

Setting AP connection priority and specifying a backup AC

About this task

Set a higher AP connection priority for the master AC to ensure that APs can associate with the master AC first.

After an AP establishes a CAPWAP tunnel with the master AC, the AP will establish a backup CAPWAP tunnel with the specified backup AC.

Procedure

1.     Enter system view.

system-view

2.     Enter AP view or AP group view.

¡     Enter AP view.

wlan ap ap-name

¡     Enter AP group view.

wlan ap-group group-name

3.     Set the AP connection priority.

priority priority

By default:

¡     In AP view, an AP uses the configuration in AP group view.

¡     In AP group view, the AP connection priority is 4.

4.     Specify a backup AC.

backup-ac { ip ipv4-address | ipv6 ipv6-address }

By default:

¡     In AP view, an AP uses the configuration in AP group view.

¡     In AP group view, no backup AC is specified.

Configuring master CAPWAP tunnel preemption

About this task

This feature enables a backup CAPWAP tunnel to become a master tunnel after the specified delay time if the backup AC has higher AP connection priority than the master AC.

Procedure

1.     Enter system view.

system-view

2.     Enter AP view, AP group view, or global configuration view.

¡     Enter AP view.

wlan ap ap-name

¡     Enter AP group view.

wlan ap-group group-name

¡     Enter global configuration view.

wlan global-configuration

3.     Configure master CAPWAP tunnel preemption.

wlan tunnel-preempt { disable | enable }

By default:

¡     In AP view, an AP uses the configuration in AP group view. If no configuration exists in AP group view, the AP uses the configuration in global configuration view.

¡     In AP group view, an AP uses the configuration in global configuration view.

¡     In global configuration view, master CAPWAP tunnel preemption is disabled.

Dual-link backup configuration examples

Example: Configuring dual-link backup

Network configuration

As shown in Figure1-2, configure AC 1 to act as the master AC and AC 2 as the backup AC. When AC 1 fails and AC 2 takes over, the AP can communicate through AC 2. Configure the master CAPWAP tunnel preemption feature on the two ACs so that the AP reconnects to AC 1 when AC 1 recovers.

Figure1-2 Network diagram

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Procedure

1.     Configure AC 1:

# Create VLAN-interface 1 and assign an IP address to it.

<AC1> system-view

[AC1] interface vlan-interface 1

[AC1-Vlan-interface1] ip address 10.1.1.1 24

[AC1-Vlan-interface1] quit

# Create an AP named ap1, and specify the AP model and serial ID. Set the AP connection priority to 7.

[AC1] wlan ap ap1 model WA6330

[AC1-wlan-ap-ap1] serial-id 219801A28N819CE0002T

[AC1-wlan-ap-ap1] priority 7

# Specify a backup AC.

[AC1-wlan-ap-ap1] backup-ac ip 11.1.1.1

# Enable master CAPWAP tunnel preemption.

[AC1-wlan-ap-ap1] wlan tunnel-preempt enable

[AC1-wlan-ap-ap1] quit

2.     Configure AC 2:

# Create VLAN-interface 1 and assign an IP address to it.

<AC2> system-view

[AC2] interface Vlan-interface 1

[AC2-Vlan-interface1] ip address 11.1.1.1 24

[AC2-Vlan-interface1] quit

# Create an AP named ap1, and specify the AP model and serial ID. Set the AP connection priority to 5.

[AC2] wlan ap ap1 model WA6330

[AC2-wlan-ap-ap1] serial-id 219801A28N819CE0002T

[AC2-wlan-ap-ap1] priority 5

# Specify a backup AC.

[AC2-wlan-ap-ap1] backup-ac ip 10.1.1.1

# Enable master CAPWAP tunnel preemption.

[AC2-wlan-ap-ap1] wlan tunnel-preempt enable

[AC2-wlan-ap-ap1] quit

Verifying the configuration

# Get the AP online on AC 1. (Details not shown.)

# Shut down VLAN-interface 1 on AC 1 and wait no longer than 3 minutes, during which service interruption occurs. (Details not shown.)

# Verify that the AP comes online on AC 2 and the AP state is R/M on AC 2. (Details not shown.)

# Bring up VLAN-interface 1 on AC 1. (Details not shown.)

# Verify that the AP comes online on AC 1 again and the AP state is R/M on AC 1 and R/B in AC 2. (Details not shown.)