Summary:How to troubleshoot smartphone or tablet that can't connect to Wi-Fi network due to legacy data rates (e.g., 802.11a, 802.11b and 802.11g).
Problem:Staff member's personal smartphone won't connect to the guest Wi-Fi network. All other devices connect to wireless network without issues.
- Older Kyocera Android phone.
- Problem device only connects with 2.4GHz radios.
Topology:Multiple access point and wireless controller. Single 2.4GHz SSID broadcast throughout the office. Recent changes were made to roaming, data rates/ cell size, and power tuning (background). Independent BSSIDs broadcast on separate radios: 802.11na and 802.11ng. Legacy 802.11b data rates are disabled. The network continues support for 802.11G data rates (i.e., 54 Mbps):
set service-profile Guest_2.4 transmit-rate 11g mandatory 12,24.0,36.0,48.0,54.0 disabled 1.0,2.0,5.5,6.0,9.0,11.0,18.0 beacon-rate 24.0 multicast-rate AUTO
- Identify client session:
*WLC# sh sessions network verbose Name: last-resort-Guest 2.4GHz-570 SSID: Guest 2.4GHz MAC: 6c:xx:xx:xx:xx:xx AP/Radio: 1/1 State: DEASSOCIATED Device type: android-generic (AAA) Radio type: 802.11ng Last packet rate: 6.0 Mb/s Last packet RSSI: -49 dBm Last packet SNR: 46
- Session state is deassociated.
- Excessive of roaming attempts.
- Good signal strength and SNR.
- Last packet rate is only 6.0 Mb/s.
- Enable log tracing to debug connection attempts:
*WLC#set log trace enable severity debugLog Interpretation:
*WLC#set trace dot1x level 10 mac
*WLC#set trace sm level 10 mac
*WLC#sh log trace
SM Apr 14 13:45:08.197931 DEBUG SM-EVENT: Cannot set ipaddr for 6c:76:60:59:9e:6a
SM Apr 14 13:45:08.743477 DEBUG sm_do_flood_announce: 6c:76:60:59:9e:6a flood announce
SM Apr 14 13:45:16.176513 DEBUG SM-EVENT: (4601) rssi -69, rate code 0x0018, idle 48 secs
SM Apr 14 13:45:16.176661 DEBUG SM-EVENT: (4601) idle timer 132755 left, reset to 132000 ms
SM Apr 14 13:45:16.177599 DEBUG SM-EVENT: (4556) rssi -56, rate code 0x0018, idle 9 secs
SM Apr 14 13:45:16.177756 DEBUG SM-EVENT: (4556) idle timer 150259 left, reset to 171000 ms
SM Apr 14 13:45:16.179532 DEBUG SM-EVENT: (5415) rssi -76, rate code 0x0018, idle 20 secs
SM Apr 14 13:45:16.179653 DEBUG SM-EVENT: (5415) idle timer is tracking (160258 to go)
SM Apr 14 13:45:16.180066 DEBUG SM-EVENT: (4551) rssi -63, rate code 0x0018, idle 6 secs
SM Apr 14 11:12:44.674414 DEBUG SM-DOT11: sm_dot11_handle_deassociate: ev type 5 (good), token 0, mac 6c:76:60:59:9e:6a
SM Apr 14 11:12:44.674576 DEBUG SM-STATE: (2462) mac 6c:76:60:59:9e:6a, flags 1801800028834dh, to change state ACTIVE -> DEASSOCIATED, by sm_dot11_handle_deassociate
- SM=Session Management.
- SM-DOT11=World Mode Multi-Domain Operation. The DOT11D option makes access points advertise local settings, such as frequencies and power levels.
- Rate code 0x0018 = 11Mb per Multi-band Atheros Wi-Fi (MADwifi) 5212.
- Check the configuration for frequency or power restrictions:
set service-profile Guest_2.4 transmit-rate 11g mandatory 12,24.0,36.0,48.0,54.0 disabled 1.0,2.0,5.5,6.0,9.0,11.0,18.0 beacon-rate 24.0 multicast-rate AUTOSnap! The service profile indicates that devices must connect at a minimum, 12Mbps -normally good policy. However, we have a single client that can only connect at 6Mbps.
- Remove 6Mbps from the list of disabled data rates. N.B., Legacy devices on the BSSID has a negative impact for the entire wi-fi network. Is one person worth the trouble? It certainly is if that person is your boss!
- Create a dedicated legacy SSID -diplomatic solution.
- Ask the employee to get rid of the stone-age device! Suggest or provide a modern device that handles 802.11na!