WLAN网络优化故障案例

01

现象描述

如下图所示，STA不关联或不漫游至就近的AP 2，而是主动关联了AP 13。

02

原因分析

STA使用的某网卡，仅支持2.4G bgn协议，相对于13信道，更偏爱1~11信道，即在STA同时收到13信道和其它信道相同的SSID时，更易连入非13信道的AP。

03

操作步骤

1. 查看AP 2和AP 13信道及功率情况。

a）执行命令display radio查看AP的发射功率和信道。

[AC] displayradio ap-id 2

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AP IDName RfID Band TypeST CH/BW CE/MESTA CU WM

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2 xxxx0 2.4G 11ax on 13/20M 20/292 16% normal

2 xxxx1 5G 11ax on52/40M+ 28/30 11% normal

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Total:2

[AC] displayradio ap-id 13

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AP IDName RfID BandType ST CH/BWCE/ME STA CUWM

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13 xxxx0 2.4G 11axon 9/20M 12/29 018% normal

13 xxxx1 5G 11ax on44/40M+ 28/30 02% normal

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b）执行命令display station sta-mac查看终端上报的AP功率情况，确认在STA上接收到就近AP（AP 2）的场强比接收到的AP 13的场强更强。

[AC-wlan-view]display station neighbor sta-mac sta-mac

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DeviceMAC Device ID Device Name Radio ID ChannelProbe info(RSSI/HHSS) 11kinfo[RCPI/RSNI/HHSS]

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xxxx-xxxx-0410 13AP13 0 9 -67/2035 180/ - /2030

xxxx-xxxx-0490 2AP2 0 13 -45/2047 184/ - /2009

c）执行命令display ap neighbor ap-id 13查看AP 13的邻居信息，确认AP 2是AP 13的邻居AP且相比其他邻居AP的场强更强。

[AC-wlan-view]display ap neighbor ap-id 13

Radio: RadioID of AP

In controlAP:

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Radio AP IDAP name Channel Received RSSI(dbm) RSSI pathloss(db) RSRP pathloss(db) Last Update Time

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0 12AP12 13 -76 105 108 2021-06-27/2008

0 2AP2 13 -57 86 87 2021-06-27/2008

2. 检查AP对终端的漫游引导动作。a）查看智能漫游配置，AC上正常配置了智能漫游功能。

[AC-wlan-view]rrm-profile name default

[AC-wlan-rrm-prof-default]display this

#

smart-roamroam-threshold snr 35

smart-roamquick-kickoff-threshold snr 10

sta-load-balancedynamic disable

#

b）分别在AP和AC上查看STA的漫游标志。

# 在AC上查看终端信息，结果显示为粘性终端。

[AC] displaystation sta-mac sta-mac

Autonavigationroaming optimization support : No

Available forroaming : Yes

Stickystation or not : Yes

Aimlessroaming support in sticky state :Yes

Stationdevice type : -

# 在AC上查看终端迁移记录，可以观察到终端没有被迁移的目标AP，也就是终端被盲切了，而且终端最终还是关联了AP 13，也就是终端未能迁移成功。

[AC-wlan-view]display station steer-history | include sta-mac

S/T/A:Source/Target/Actual

Flag:V[Voice/Video/ActiveSTA]

BTM successtimes/BTM total times:441/919

Deauthsuccess times/Deauth total times:0/0

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Time Sta Device(S/T/A) Radio(S/T/A)Rssi(S/T/A) Reason Move-mode BTM_CODEFlag Result

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2021-06-27/1907 sta-mac 13/-/13 0/-/0 -71/-/-71 Sticky BTM - -Not Move

2021-06-27/1900 sta-mac 13/-/13 0/-/0 -71/-/-72 Sticky BTM - -Not Move

# 在AP执行命令displayumac station sticky-table，发现该终端被标志为粘性终端。

[AP13-diagnose]display umac station sticky-table

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STA MAC Frequency SNRState SSID

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sta-mac 2.4G 29 sticky office

结合上述信息分析可知，STA被盲切，但STA并未关联就近的AP 2。按正常情况，即使终端首次接入网络不关联AP 2，也会被智能漫游功能迁移到AP 2上，而实际STA并未及时关联至AP 2，而是关联到了远端的AP 13。

3. 尝试将AP 2（信道13 ）与AP 13（信道9）进行信道调换测试，确认STA对信道是否有特殊偏爱。

[AC] wlan

[AC-wlan-view]ap-id 2

[AC-wlan-ap-2]radio 0

[AC-wlan-radio-2/0]calibrate auto-channel-select disable

[AC-wlan-radio-2/0]channel 20mhz 9

Warning: Thisaction may cause service interruption. Continue?[Y/N]y

4. 将2.4G射频的调优信道集设置为1，6，11，进行调优之后测试，该STA接入和漫游均正常。[AC]wlan [AC-wlan-view]regulatory-domain-profile name default[AC-wlan-regulate-domain-default]dca-channel 2.4g channel-set 1,6,11

审核编辑 ：李倩