Cisco Catalyst IW9165E Rugged Access Point and Wireless Client Configuration Guide, Cisco IOS XE 26.2.x
Cisco Catalyst IW9165E Rugged Access Point and Wireless Client Configuration Guide, Cisco IOS XE 26.2.x
Describes the configuration of aux-scan mode on WGB radio 2 to enhance roaming performance. This feature allows users to select between scanning-only or handoff modes.
Configure aux-scan mode as either scanning-only or handoff mode on WGB radio 2 (5 GHz) to improve roaming performance.
The scanning-only mode is a wireless access point operational mode that:
enables radio operation exclusively for scanning,
continuously monitors the wireless environment to collect data on network performance, interference, and rogue devices, and
allows configuration of scanning parameters such as channel lists and scanning intervals.
When slot 2 radio is configured in scanning-only mode, slot 1 (5G) radio is always selected as the uplink. Slot 2 (5G) radio continues to scan the configured SSID based on the channel list. By default, the channel list contains all supported 5G channels (based on reg domain). You can configure the scanning list manually, or the device can learn it from 802.11v.
When roaming is triggered, the algorithm looks for candidates in the scanning table and skips the scanning phase if the table is not empty. The WGB then associates to the selected candidate AP.
Enable the device to operate in scan-only mode, facilitating network monitoring and assessment without transmitting data.
Device# configure dot11Radio 2 mode scan onlyAdjust the scanning table timer to optimize the candidate AP selection process and prevent roaming failures caused by outdated RSSI values.
The scanning table maintains a list of candidate APs detected by the device. By default, entries in this table expire after 1200 milliseconds. Modifying the expiration timer may help improve roaming efficiency by allowing more time for RSSI updates.
Device#configure wgb scan timeout 1500
Scanning AP expire time is from 1 to 5000.
From the scanning table, the AP selects the candidate with the best RSSI value. However, sometimes the RSSI values might not be updated and it lead to roaming failures.
Perform this task to manually add or remove channels from the channel list to optimize wireless network performance or for specific configuration requirements.
| Option | Description |
|---|---|
| Add a channel to the channel list | Use the configure wgb mobile station interface dot11Radio interface scan channel add command.
|
| Remove a channel from the channel list | Use the configure wgb mobile station interface dot11Radio interface scan channel delete command.
|
Perform this task to confirm the current AP scanning details and identify the best AP for optimal connectivity.
Device#show wgb scan
Best AP expire time: 5000 ms
************[ AP List ]***************
BSSID RSSI CHANNEL Time
FC:58:9A:15:E2:4F 84 136 1531
FC:58:9A:15:DE:4F 37 136 41
***********[ Best AP ]****************
BSSID RSSI CHANNEL Time
FC:58:9A:15:DE:4F 37 136 41
An Auxiliary Scanning handoff mode is a wireless radio configuration that
allows both radios (radio 1 and radio 2) to serve as uplink connections,
supports dynamic switching of roles and traffic between radios after each roaming event, and
enables efficient roaming by using a scanning radio to associate with the best available access point.
The Auxiliary Scanning list can be manually configured or learned automatically using the 802.11v standard. This handoff mode improves roaming performance by quickly associating with the best available access point.
The radio 2 shares the same MAC address with the radio 1 and supports scanning, association, and data serving. Both radios can operate in either a serving or scanning role. After each roaming event, the roles and traffic automatically switch between radio 1 and radio 2.
When roaming is triggered, the system algorithm checks the scanning database for the best AP to establish a connection. WGB always uses the radio in the scanning role to complete the roaming association with the new AP. This configuration reduces roaming interruptions to between 20 and 50 milliseconds.
This table shows an example of aux-scan handoff radio mode configuration on IW9165E:
|
Slot 0 (2.4 G) |
Slot 1 (5G) |
Slot 2 (5G only) |
Slot 3 (scanning radio) |
|---|---|---|---|
|
N/A |
WGB |
Scan handoff |
N/A |
This table shows how long roaming interruptions last for different methods when using three different modes:
|
Roaming interruption time |
Normal channel setting |
Auxiliary Scanning only |
Auxiliary Scanning Handoff |
|---|---|---|---|
|
Scanning |
(40+20)*3=180 ms |
0-40 ms |
0 ms |
|
Association |
30-80 ms |
30-80 ms |
20-50 ms |
|
Total |
~210 ms |
70-120 ms |
20-50 ms |
Perform this task to configure the WGB slot 2 radio in auxiliary-scan handoff mode, ensuring seamless connectivity and optimized network performance.
Auxiliary-scan handoff mode allows the radio to scan for available access points without interrupting active connections. This feature is particularly useful for improving handoff reliability in environments with multiple access points.
Perform this task to confirm the current role of each radio and analyze the auxiliary scanning results, including the best AP selection and performance metrics.
WGB scan provides detailed information about the auxiliary scanning process for each radio. This data helps to determine the best AP based on signal strength (RSSI), channel, and scan time.
Device#show wgb scan
Best AP expire time: 2500 ms
Aux Scanning Radio Results (slot 2)
************[ AP List ]***************
BSSID RSSI CHANNEL Time
FC:58:9A:15:DE:4E 54 153 57
FC:58:9A:15:E2:4E 71 153 64
***********[ Best AP ]****************
BSSID RSSI CHANNEL Time
FC:58:9A:15:DE:4E 54 153 57
Aux Serving Radio Results
************[ AP List ]***************
BSSID RSSI CHANNEL Time
FC:58:9A:15:DE:4E 58 153 57
FC:58:9A:15:E2:4E 75 153 133
***********[ Best AP ]****************
BSSID RSSI CHANNEL Time
FC:58:9A:15:DE:4E 58 153 57