The Link Setup Rate of STAs Is Low
Symptom
The link setup rate between a STA and an AP is low.
Possible Causes
- The uplink and downlink signal strengths of the AP and STA are weak.
- The radio mode, frequency bandwidth, encryption mode, or WMM function is incorrectly configured.
- The STA supports only a few spatial streams.
- Interference exists on the air interface.
- The STA is working in power-saving mode.
Troubleshooting Procedure
- Check the signal strength of the STA.
The received signal strength indicator (RSSI) of a STA is affected by the transmit power of the associated AP's radio, or distance or obstacles between the STA and AP antennas.
Run the display station all | include mac-address command on the AC to check the STA's RSSI and negotiated rate.
<AC> display station all | include cc3d-828a-bfec Rf/WLAN: Radio ID/WLAN ID Rx/Tx: link receive rate/link transmit rate(Mbps) ------------------------------------------------------------------------------------------------------------ STA MAC AP ID Ap name Rf/WLAN Band Type Rx/Tx RSSI VLAN IP address SSID ------------------------------------------------------------------------------------------------------------ cc3d-828a-bfec 25 ap-yuan 0/1 2.4G 11n 123/98 -46 500 10.1.1.253 r6c10-test ------------------------------------------------------------------------------------------------------------ Total: 1 2.4G: 1 5G: 0
The RX value displayed in the command output may be slightly different from the rate displayed on the STA.
If the STA's RSSI is less than -75 dBm, perform the following operations.
- Adjust the AP's transmit power.
# Run the display radio ap-id ap-id command on the AC to check whether the transmit power of the AP radio is the maximum power.
<AC> display radio ap-id 0 CH/BW:Channel/Bandwidth CE:Current EIRP (dBm) ME:Max EIRP (dBm) CU:Channel utilization ST:Status WM:Working Mode (normal/monitor/monitor dual-band-scan/monitor proxy dual-band-scan) ------------------------------------------------------------------------------------ AP ID Name RfID Band Type ST CH/BW CE/ME STA CU WM ------------------------------------------------------------------------------------ 0 60de-4474-9640 0 2.4G bgn on 6/20M 11/24 0 55% normal 0 60de-4474-9640 1 5G an on 56/20M 25/25 0 3% normal ------------------------------------------------------------------------------------ Total:2
# If the transmit power of the AP radio is not the maximum power, run the eirp eirp command on the AC to set the transmit power of the AP radio to the maximum value so that the RSSI increases when the STA is associated with the AP.
Before manually adjusting the transmit power of a radio, you can use automatic radio calibration to adjust the radio power. If the expected result is not achieved, disable automatic radio calibration and then manually adjust the transmit power of the radio.
<AC> system-view [AC] wlan [AC-wlan-view] ap-id 0 [AC-wlan-ap-0] radio 0 [AC-wlan-radio-0/0] eirp 24
- Check whether the STA is far away from the AP's antennas and whether obstacles exist between them.
Generally, a distance of more than 50 m between a STA and an AP's antennas increases signal attenuation. In addition, AP signals attenuate if obstacles exist between a STA and an AP's antennas.
If the STA's RSSI is low due to the preceding reasons, you can move the STA closer to the AP to increase the STA's RSSI. It is recommended that a STA's RSSI be greater than -65 dBm.
- Adjust the AP's transmit power.
- Check STA association details.
The radio mode associated with the STA, encryption mode configured on the AP, spatial streams supported by the STA, and channel bandwidth configured on the AP are related to the negotiated rate. You need to check these indicators when the STA is associated with the AP.
[AC-wlan-view] display station sta-mac cc3d-828a-bfec ------------------------------------------------------------------------------ Station MAC-address : cc3d-828a-bfec Station IP-address : 10.1.1.253 Station gateway : 10.1.1.1 Associated SSID : r6c10-test Station online time(ddd:hh:mm:ss) : 000:06:30:19 ...... Station's radio mode : 11n Station's AP Name : cc53-b5ee-39e0 Station's Radio ID : 0 Station's Authentication Method : WPA2-PSK Station's Cipher Type : AES Station's User Name : cc3d828abfec Station's Vlan ID : 500 Station's Channel Band-width : 20MHz Station's asso BSSID : cc53-b5ee-39e0 Station's state : Asso with auth Station's QoS Mode : WMM Station's HT Mode : HT20 Station's MCS value : 15 Station's NSS value : 2 Station's Short GI : nonsupport ......
- Check whether the radio mode is correct.The STA association rate varies according to the radio mode. For example, the maximum association rate in 802.11g mode is only 54 Mbit/s. If the AP supports 802.11n and the associated radio mode is not 802.11n, perform the following operations:
- Check whether a fixed radio mode has been configured for the STA.
Check the Station's radio mode field. If a fixed radio mode has been configured, run the following commands to restore the default radio mode, that is, 802.11b/g/n at the 2.4 GHz frequency band or 802.11ac at the 5 GHz frequency band.
<AC> system-view [AC] wlan [AC-wlan-view] radio-2g-profile name huawei [AC-wlan-radio-2g-prof-huawei] display this # radio-type dot11b # return [AC-wlan-radio-2g-prof-huawei] undo radio-type [AC-wlan-radio-2g-prof-huawei] display this # return [AC-wlan-radio-2g-prof-huawei] quit
- Check the radio mode supported by the STA's NIC.
If the STA does not support 802.11n or 802.11ac, the STA can only associate with an AP in 802.11b/g/a mode, and the maximum link setup rate can reach only 54 Mbit/s. You can use another STA supporting 802.11n or 802.11ac for testing again.
- Check whether the AP's encryption mode is correctly configured.
Check the Station's Authentication Method and Station's Cipher Type fields. If the encryption mode configured on the AP is WEP+PSK+TKIP, the STA associates with the AP in 802.11g mode because the TKIP encryption mode is not defined in 802.11n. The maximum link setup rate is 54 Mbit/s. You can run the following commands to change the encryption mode of the AP.
[AC-wlan-view] security-profile name huawei [AC-wlan-sec-prof-huawei] security wpa2 psk pass-phrase a1234567 aes Warning: This action may cause service interruption. Continue?[Y/N]y [AC-wlan-sec-prof-huawei] quit
- Check whether WMM is enabled.
Check the Station's QoS Mode field. If the field value is displayed as NULL, WMM is disabled. If WMM is disabled, the STA can associate with the AP only in 802.11b/g/a mode, and the maximum link setup rate can reach only 54 Mbit/s. Run the following commands to enable WMM in the radio profile.
[AC-wlan-view] radio-2g-profile name huawei [AC-wlan-radio-2g-prof-huawei] undo wmm disable
- Check whether a fixed radio mode has been configured for the STA.
- Check whether the channel bandwidth is configured correctly.
The STA's channel bandwidth refers to the amount of data that can be transmitted within a specific time period, that is, the capability of a STA to transmit data through a communication channel, in Hz. Currently, three channel bandwidth types are provided: 20 MHz, 40 MHz, and 80 MHz. Only STAs working in 802.11ac support 80 MHz channel bandwidth. The link setup rate varies depending on channel bandwidth. The following table describes the maximum link setup rates of STAs supporting different channel bandwidths in 802.11n mode. If the actual link setup rate of a STA has reached the maximum link setup rate corresponding to the configured channel bandwidth, change the channel bandwidth to enable the STA to obtain a higher link setup rate.
Table 6-2 Link setup rate in 802.11n modeNumber of Spatial Streams
GI Mode
Bandwidth
Maximum Link Setup Rate
Single
normal
HT20
65 Mbit/s
Single
normal
HT40
135 Mbit/s
Single
short
HT20
72.2 Mbit/s
Single
short
HT40
150 Mbit/s
Two
normal
HT20
130 Mbit/s
Two
normal
HT40
270 Mbit/s
Two
short
HT20
144.4 Mbit/s
Two
short
HT40
300 Mbit/s
Three
normal
HT20
195 Mbit/s
Three
normal
HT40
405 Mbit/s
Three
short
HT20
216.7 Mbit/s
Three
short
HT40
450 Mbit/s
Check the Station's Channel Band-width and Station's HT Mode fields. If the STA's channel bandwidth is not properly configured, run the following commands to change the channel bandwidth. For example, it is recommended that the channel bandwidth of a STA supporting 802.11ac be set to 80 MHz.
You can run the following commands to configure the channel bandwidth (5G is used as an example).
<AC> system-view [AC] wlan [AC-wlan-view] ap-id 0 [AC-wlan-ap-0] radio 1 [AC-wlan-radio-0/1] channel 80mhz 149
The actual link setup rate of a STA may be lower than the maximum link setup rate due to interference on the air interface.
In 80211.b/g/a mode, changing the bandwidth does not affect the negotiated rate.
If both a STA and an AP support 802.11ac, the 80 MHz channel bandwidth can be configured.
When configuring a channel bandwidth, you need to configure the channel bandwidth supported by the AP. For example, non-802.11ac APs do not support the 80 MHz channel bandwidth.
- Check the number of spatial streams supported by the STA.
The STA supports single, two, and three spatial streams. The negotiated rate varies with the number of spatial streams. The more the spatial streams, the higher the negotiated rate. In addition, the number of spatial streams is an inherent attribute of the STA.
Check the Station's MCS value field. For a STA supporting 802.11n, a field value ranging from 0 to 7 indicates that the STA supports a single spatial stream, a field value ranging from 8 to 15 indicates that the STA supports two spatial streams, and a field value ranging from 16 to 23 indicates that the STA supports three spatial streams.
For 802.11ac STAs, the Station's NSS value field is displayed in the command output. The value 1 indicates that the STA supports a single spatial stream, the value 2 indicates that the STA supports two spatial streams, and the value 3 indicates that the STA supports three spatial streams. In addition, the negotiated rate of 802.11ac is related to the Station's MCS value field. For example, if a STA supports two spatial streams, the maximum negotiated rate is 130 Mbit/s when the channel bandwidth is HT20 and the GI mode is normal.
Table 6-2 lists the maximum rate that can be reached by a STA. The negotiated rate may be smaller than the maximum value due to factors such as interferences on an air interface.
The GI mode also affects the actual link setup rate of a STA. On a high-quality network, you can set the GI mode to short to provide a higher link setup rate.
- Check whether the STA is in power-saving mode.
<AC> display station sta-mac 482c-a042-8227 ------------------------------------------------------------------------------ Station MAC-address : 482c-a042-8227 Station IP-address : FE80::D287:F82B:9D2C:827C : 10.10.10.49 Station gateway : 10.10.10.1 Associated SSID : test Station online time(ddd:hh:mm:ss) : 000:00:03:36 ...... Station current state ...... Power save mode enabled : YES ......When the STA enters the power-saving mode, its packet transmission delay increases. The actual packet transmission delay is related to the interval at which beacon frames are sent. A smaller interval at which beacon frames are sent indicates a shorter packet forwarding delay.
In this case, you can perform the fast ping to the STA on the STA's gateway to ensure that the STA does not enter the power-saving state. Then, check the link setup rate of the STA. If the link setup rate is normal, the low link setup rate is caused by the STA's power-saving state.
<AC> ping -m 1 -c 1000 x.x.x.x
- Check whether the radio mode is correct.
- Check whether interference exists on the air interface.
The negotiated rate between a STA and an AP is affected by the air interface environment. Severe interference on the air interface will reduce the negotiated rate.
# Check the AP channel utilization on the AC to determine interference on the air interface.
[AC-wlan-view] display radio ap-id 0 CH/BW:Channel/Bandwidth CE:Current EIRP (dBm) ME:Max EIRP (dBm) CU:Channel utilization ST:Status WM:Working Mode (normal/monitor/monitor dual-band-scan/monitor proxy dual-band-scan) ------------------------------------------------------------------------------------ AP ID Name RfID Band Type ST CH/BW CE/ME STA CU WM ------------------------------------------------------------------------------------ 0 60de-4474-9640 0 2.4G bgn on 6/20M 24/24 0 55% normal 0 60de-4474-9640 1 5G an on 56/20M 25/25 0 3% normal ------------------------------------------------------------------------------------ Total:2
# If the channel utilization of an AP is greater than 50%, the channel utilization is high and interference on the air interface is high. Check the air interface environment to locate interference.
<AC6605> display ap radio-environment ap-id 0 radio 0 Info: This operation may take a few seconds. Please wait for a moment.done. p: permit i: interference Ch: Channel NF: Noise Floor CommIf: Common-Channel Interference AdjaceIf: Adjacent-Channel Interference #AP: Number of APs detected Radio: 0 ScanChannel: 1 WorkChannel: 1 ScanCycle: 1 --------------------------------------------------------------------------- Ch NF CU(%) CommIf(%) AdjaceIf(%) SINR #APs --------------------------------------------------------------------------- 1 -105 75 19 - 245 57 ...... --------------------------------------------------------------------------- Total: 13 --------------------------------------------------------------------------- Ch MAC Type RSSI SSID --------------------------------------------------------------------------- 1 c88d-833a-8d41 i -65 xw9-2g-tunnel ...... ------------------------------------------------ Total: 177
You can run this command to query the number and strength of interference devices on each channel.
The result of the air interface environment scanning is not displayed during the first query. Therefore, you need to run this command again.
When AP radio scanning is enabled using this command, the air interface performance of the AP is affected. If this command is not executed again after 5 minutes, AP radio scanning is automatically disabled.
If the radio radio-id parameter is not specified, air interface environment information about all radios of the AP is displayed.
For interference problems, use the following solutions:
- Change the AP's working channel to a channel with less interference. (2.4 GHz is used as an example.)
<AC> system-view [AC] wlan [AC-wlan-view] ap-id 0 [AC-wlan-ap-0] radio 0 [AC-wlan-radio-0/0] channel 20mhz 6
When configuring channels, you are advised to configure non-overlapping channels to reduce adjacent-channel interference. For example, configure channels 1, 6, and 11 at the 2.4 GHz frequency band.
- Search for and remove interference sources.
- Change the AP's working channel to a channel with less interference. (2.4 GHz is used as an example.)
- Collect fault information.
- Check AC version information.
[AC-diagnose] vrbd
- Check the AC configuration.
<AC> display current-configuration
- Check AP version information.
[Huawei-diagnose] vrbd
- Collect AP information by one click.
<Huawei> display diagnostic-information saved-file <Huawei> display diagnostic-information
- Collect kernel logs of the AP.
[Huawei-diagnose] display kernel-logbuf record-range 1 [Huawei-diagnose] display kernel-logbuf record-range 2 [Huawei-diagnose] display kernel-logbuf record-range 3
If the problem persists for a long time, export logs on the AP or AC as follows.
<fce3-3cb6-47e0> save logfile [fce3-3cb6-47e0-diagnose] save diag-logfile <fce3-3cb6-47e0> cd logfile/ <fce3-3cb6-47e0> dir Directory of flash:/logfile/ Idx Attr Size(Byte) Date Time(LMT) FileName 0 -ro- 1,113,850 Aug 31 2015 11:26:57 2015-08-31.12-29-00.dblg 1 -ro- 1,113,970 Aug 31 2015 19:45:02 2015-08-31.23-14-59.dblg 2 -ro- 1,113,920 May 06 2016 08:42:07 2016-05-06.08-47-07.dblg 3 -ro- 1,113,472 May 11 2016 16:19:54 2016-06-09.17-15-52.dblg 4 -ro- 1,114,104 Jun 14 2016 17:55:56 2016-06-14.18-29-52.dblg 5 -ro- 1,114,031 Jun 14 2016 22:22:06 2016-06-14.22-54-08.dblg 6 -ro- 1,113,835 Jun 17 2016 17:29:24 2016-06-17.18-08-54.dblg 7 -ro- 1,113,843 Jun 17 2016 20:34:50 2016-06-17.20-47-59.dblg 8 -ro- 1,113,743 Jun 22 2016 20:06:19 2016-06-22.20-50-06.dblg 9 -ro- 1,113,271 Jun 28 2016 16:58:37 2016-06-28.19-58-45.dblg 10 -ro- 1,113,494 Jun 29 2016 17:33:23 2016-06-29.18-32-36.dblg 11 -ro- 1,113,824 Jun 30 2016 01:22:38 2016-06-30.02-19-21.dblg 12 -ro- 1,113,773 Jun 30 2016 09:10:31 2016-06-30.10-09-39.dblg 13 -ro- 1,125,418 Jun 30 2016 09:26:03 2016-06-30.12-25-03.log 14 -ro- 1,113,801 Jul 11 2016 09:59:38 2016-07-11.10-13-26.dblg 15 -ro- 1,113,732 Jul 13 2016 15:41:02 2016-07-13.15-54-31.dblg 16 -ro- 1,129,531 Jul 13 2016 19:55:33 2016-07-15.10-37-46.dblg 17 -ro- 1,113,787 Nov 26 2018 21:54:45 2018-11-27.01-02-52.dblg 18 -ro- 1,113,604 Nov 27 2018 22:56:38 2018-11-28.00-20-24.dblg 19 -ro- 1,113,723 Nov 28 2018 07:37:57 2018-11-28.08-40-58.dblg 20 -ro- 1,113,744 Nov 28 2018 15:14:40 2018-11-28.16-10-55.dblg 21 -rw- 384,570 Jul 19 2016 10:07:11 log.dblg 22 -rw- 681,533 Jul 19 2016 10:06:57 log.log 11,144 KB total (1,512 KB free)You must log in to the AP to collect AP information.
In V200R008C10 and later versions, you only need to run the save logfile command. After the logs are saved, use FTP or TFTP to export the log files with the extension name .log and .dblg in the corresponding time period.
Information collection is mainly performed in the diagnostic view. To enter the diagnostic view, run the following commands.
<Huawei> system-view [Huawei] diagnose
- Check AC version information.
