AC6605 Access Controller
Dual-Link Backup White Paper
1
Dual-Link Backup
Issue 01 (2012-05-30)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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interface GigabitEthernet0/0/1
description connect to active AC
port link-type trunk
port trunk pvid vlan 3010
port trunk allow-pass vlan 40 3010 3931
#
interface GigabitEthernet0/0/2
description connect to standby AC
port link-type trunk
port trunk pvid vlan 3010
port trunk allow-pass vlan 40 3010 3931
#
interface GigabitEthernet0/0/3
description connect to AP
port link-type trunk
port trunk pvid vlan 40
port trunk allow-pass vlan 2 to 4094
#
return
The preceding configuration files show the basic configurations used for dual-link backup in
Layer 3 chain networking. You can configure services on the ACs and the switch after
completing the preceding configurations.
1.4.2 Tunnel Forwarding in Layer 2 Branched Networking
As shown in Figure 1-15, two ACs are deployed in a Layer 2 branched networking and work
dual-link backup mode to improve network reliability and ensure stable wireless services.
Data packets from STAs are forwarded through tunnels. This networking applies to WLAN
networks where ACs are deployed close to each other and APs are distributed dispersedly. The
ACs belong to the same LAN as APs, and IP addresses of ACs and APs are on the same
network segment. This networking does not require high AC performance.
AC1 is the active AC, and AC2 is the standby AC. It is recommended that you manually add
offline APs to the ACs. Perform the same service configurations (including user
authentication configuration) on the two ACs. Before enabling dual-link backup, complete the
tunnel configuration and commit the configuration on AC1 and AC2. If you enable dual-link
backup before committing the tunnel configuration, the configuration cannot be committed on
the standby AC. As a result, the tunnel interface cannot be enabled and therefore services
cannot be switched to the standby AC after an active/standby switchover.
Configuration on the ACs is as follows:
Configure management VLAN 3010 and service VLAN 3931 for APs. Set the
management IP address of AC1 to 19.19.19.1, and management IP address of AC2 to
19.19.19.2. Enable DHCP on AC1 and AC2.
Configure the same carrier ID for the ACs. Set the data forwarding mode to tunnel
forwarding. Enable dual-link backup and configure IP addresses and priorities for the
ACs. Ensure that the active AC has a higher priority (smaller priority value) than the
standby AC.
Configure non-overlapping IP address pools on the ACs. In this example, the IP address
pool on AC1 contains IP addresses 19.19.19.3 to 19.19.19.100, and the IP address pool
on AC2 contains IP addresses 19.19.19.101 to 19.19.19.254. Set the gateway address of
the IP address pool on AC1 to 19.19.19.1, and set the gateway address of the IP address
pool on AC2 to 19.19.19.2.