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.
8
Figure 1-3
No loop in the management VLAN of APs
AP
AP
AC2
AC1
Access switch
Access switch
Aggregation switch
Management VLANs of the aggregation switches and access switches must be configured on
the two aggregation switches and ACs; therefore, a loop is formed, as shown in Figure 1-4. To
prevent packet looping, enable MSTP or configure port isolation on the ACs or aggregation
switches. MSTP is recommended.
Figure 1-4
Loop in management VLANs of aggregation and access switches
AC2
AC1
Aggregation switch
Aggregation switch
Service VLANs of STAs also need to be configured on the two aggregation switches and ACs,
causing loops. Similarly, enabling MSTP or configuring port isolation can prevent loops in
these VLANs. Because there are many service VLANs of STAs, MSTP is recommended so
that service VLANs can be mapped to an MST instance.
APs use the same VLAN as switches or STAs.
If the AP management VLAN is the same as a VLAN of switches or STAs, a loop occurs in
this VLAN. To prevent loops in this VLAN, enable MSTP (recommended) or configure port
