Wireless Services on a STA Are Abnormal

WLAN Troubleshooting Guide

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Symptom

The signal strength is too weak to allow the STA to associate with the AP.
See section Troubleshooting: AP Fails to Go Online to rectify the fault.
Signals are normal but services are not running properly.
This section describes the method to rectify this fault.

Common Causes

The problem is usually caused by incorrect configurations, for example, the wired interface of the AP is not added to the service VLAN or the interface on the intermediate wired network is not correctly configured.

Troubleshooting Flowchart

Click to enlarge

Troubleshooting Procedure (CLI)

Check whether the vap profile and the wired interface of the AP are correctly configured.

If the AP's wired interface is directly connected to the network device or works in back-to-back relay mode, the configurations of the wired interface must be correct so that service traffic can be forwarded correctly.

For example:

[AC6605] interface GigabitEthernet 0/0/3
[AC6605-GigabitEthernet0/0/3] display this
# 
 interface GigabitEthernet0/0/3
  port link-type trunk   
  port trunk pvid vlan 149 
  port trunk allow-pass vlan 149 to 150 
  am isolate GigabitEthernet0/0/1
# 
return  
[AC6605-wlan-view] vap-profile name ap6010
[AC6605-wlan-vap-prof-ap6010] display this 
# 
 forward-mode tunnel
 service-vlan vlan-id 150
 ssid-profile ap6010 
 security-profile ap6010 
# 
return

Check whether an interface is created on the intermediate network or AC and added to the corresponding VLAN.

The Huawei network device allows data from a VLAN only when the VLAN has been created on the local device and corresponding interfaces are correctly configured (tagged or untagged mode). If the configurations are incorrect or the VLAN is not created, service data will be discarded.

[AC6605] display vlan brief  
 U:Up;D:Down;TG:Tagged;UT:Untagged;                                    
 VID  Name  Status  Ports                                                                                                   
 ------------------------------------------------------------------  
 1         enable  UT: GE0/0/4(D) GE0/0/5(D) GE0/0/6(D) GE0/0/7(D)                                                         
                      GE0/0/8(D) GE0/0/9(D) GE0/0/10(D) GE0/0/11(D)                                                       
                      GE0/0/12(D) GE0/0/13(D) GE0/0/14(D)                                                                 
                      GE0/0/15(D) GE0/0/16(D) GE0/0/17(D)                                                                 
                      GE0/0/18(D) GE0/0/19(D) GE0/0/20(D)                                                                 
                      GE0/0/21(D) GE0/0/22(D) GE0/0/23(D)                                                                 
                      GE0/0/24(D) Wlan-Dbss0(U) Wlan-Dbss1(U)                                                             
                      XGE0/0/1(D) XGE0/0/2(D)                                                                             
                      TG: GE0/0/1(U) GE0/0/3(U)                                                                               
 149      enable  UT: GE0/0/3(U)                                                                                          
                      TG: GE0/0/1(U)                                                                                          
 150      enable  UT: GE0/0/1(U)                                                                                          
                      TG: GE0/0/3(U)

Check the current VLAN configuration.

[AC6605-GigabitEthernet0/0/3] display this 
#                                                             
interface GigabitEthernet0/0/3  
port link-type trunk
port trunk pvid vlan 149 
port trunk allow-pass vlan 149 to 150  
#                                                             
return

Check interface configuration on the root AP.

To prevent such a failure, pay attention to the following points:

Configure one management VLAN and one or more service VLANs.
By default, packets sent from an AP, including the DHCP packets and CAPWAP packets are not tagged. Configure the switch interface directly connected to the AP to tag these packets with the management VLAN ID. Packets can be then sent to the DCHP server or AC through control of VLANs and routes.
Packets sent from the STA are not tagged either. Configure the AP to tag these packets with service VLAN IDs.
In direct forwarding, ensure that packets from service VLANs can pass through upstream interfaces of the AP. Configure the upstream interfaces as hybrid or trunk interfaces and to allow packets from the management VLAN and service VLANs to pass through. For example, configure the interface to allow packets from management VLAN 10 and service VLAN 20.
```
port link-type trunk 
port trunk pvid vlan 10 
port trunk allow-pass vlan 10 20 
```
or
```
port link-type hybrid 
port hybrid pvid vlan 10 
port hybrid untagged vlan 10 
port hybrid tagged vlan 20 
```
In tunnel forwarding, service packets are encapsulated in CAPWAP packets. Configure the AP's upstream interfaces as access, trunk, or hybrid interfaces and to allow only the management VLAN (allowing service VLANs may cause errors). For example, configure the interface to allow only packets from management VLAN 10.
```
port link-type access 
port default-vlan 10 
```
or
```
port link-type trunk 
port trunk pvid vlan 10 
port trunk allow-pass vlan 10 
```
or
```
port link-type hybrid 
port hybrid pvid vlan 10 
port hybrid untagged vlan 10 
```
If a Layer 3 network is deployed between the AC and AP, the AP that has obtained an IP address cannot discover the AC to register with by broadcasting CAPWAP packets. Configure DCHP Option 43 in packets to transfer both the AC's IP address and AP's IP address. Then, the AP can send unicast CAPWAP packets to discover the AC and register with the AC. You can also configure Option 15 in DNS packets to notify the AP of the AC location.
An AP can obtain an IP address using DHCP or has a static IP address manually configured. DHCP is the most commonly used method.
After changing the AP bridge role on a WDS network, you need to restart the AP to make the new role take effect; otherwise, the AP cannot register with the AC.

Troubleshooting Procedure (Web)

Check whether the VAP profile and AP's wired interface are configured correctly.
1. Choose Configuration > AC Config > Interface, select the wired interface of the AP to check the interface configuration.
2. Check the VAP profile configuration.
Check whether the corresponding VLAN has been created on the AC and intermediate network and whether interfaces have been added to the VLAN in correct modes.
A Huawei network device can forward data packets in a VLAN only if the VLAN has been created on the device and associated interfaces have been added to the VLAN in correct modes (tagged or untagged). If the VLAN does not exist on the device or interfaces are not added to the VLAN, data packets will be dropped.
1. Choose Configuration > AC Config > VLAN, create the VLAN, and add associated interfaces to the VLAN in tagged or untagged mode.
2. Select the VLAN and check the configuration. Ensure that the interfaces have been added to the VLAN in correct modes.