Example for Configuring Spectrum Analysis

WLAN V200R019C00 Typical Configuration Examples

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Service Requirements

Enterprise users can access the network through WLANs, which is the basic requirement of mobile office. Furthermore, users' services are not affected during roaming in the coverage area. The enterprise is located in an open place, and the WLAN is vulnerable to interference. When discovering severe interference on the WLAN, the network administrator can detect whether non-Wi-Fi interference exists on the WLAN through the spectrum analysis function.

Networking Requirements

Figure 5-63 Networking for configuring spectrum analysis

After a spectrum server is deployed on the network, the AP reports the spectrum scanning data and sampling data to the spectrum server through the AC. Ensure that the AC and the spectrum server can communicate with each other.

Data Planning

Table 5-67 AC data planning

Item	Data
AP group	Name: ap-group1 Referenced profiles: VAP profile wlan-net, regulatory domain profile default, 2G radio profile wlan-radio2g, 5G radio profile wlan-radio5g, and AP system profile wlan-spectrum
Air scan profile	Name: wlan-airscan Air scan interval: 8000 ms Air scan duration: 100 ms
2G radio profile	Name: wlan-radio2g Referenced profiles: air scan profile wlan-airscan
5G radio profile	Name: wlan-radio5g Referenced profiles: air scan profile wlan-airscan
AP system profile	Name: wlan-spectrum IP address of the spectrum server: 10.137.43.4 Port number of the spectrum server: 32181 Port number used by the AC to receive spectrum information (encapsulated in UDP packets) from APs when the AC is used to send data to the spectrum server: 5001 Aging time of non-Wi-Fi devices on an AC during spectrum analysis: 5 minutes

Configuration Roadmap

Configure spectrum analysis so that the APs can detect non-Wi-Fi devices and send alarms to the AC.

Configuration Notes

If a radio works in normal mode and has air scan functions (such as WIDS, spectrum analysis, and terminal positioni) enabled, the radio transmits common WLAN services and also provides the monitoring function. A transient increase in the WLAN service latency may occur, which does not affect network access. However, if any latency-sensitive service (such as videoconferencing) is running, it is recommended that a separate radio be used for air scan.
When spectrum analysis is used, the air scan interval range of 2s to 10s and the air scan period of 100 ms are recommended. This helps you obtain sufficient sampled data without compromising normal services.
The channels to be scanned for spectrum analysis are fixed as all channels supported by the corresponding country code of an AP and are irrelevant to the configuration in an air scan profile.
No ACK mechanism is provided for multicast packet transmission on air interfaces. In addition, wireless links are unstable. To ensure stable transmission of multicast packets, they are usually sent at low rates. If a large number of such multicast packets are sent from the network side, the air interfaces may be congested. You are advised to configure multicast packet suppression to reduce impact of a large number of low-rate multicast packets on the wireless network. Exercise caution when configuring the rate limit; otherwise, the multicast services may be affected.
- In direct forwarding mode, you are advised to configure multicast packet suppression on switch interfaces connected to APs.
- In tunnel forwarding mode, you are advised to configure multicast packet suppression in traffic profiles of the AC.
For details on how to configure traffic suppression, see How Do I Configure Multicast Packet Suppression to Reduce Impact of a Large Number of Low-Rate Multicast Packets on the Wireless Network?.
Configure port isolation on the interfaces of the device directly connected to APs. If port isolation is not configured and direct forwarding is used, a large number of unnecessary broadcast packets may be generated in the VLAN, blocking the network and degrading user experience.
In tunnel forwarding mode, the management VLAN and service VLAN cannot be the same. Only packets from the management VLAN are transmitted between the AC and APs. Packets from the service VLAN are not allowed between the AC and APs.

Procedure

Configure spectrum analysis.
1. Set spectrum analysis parameters.
  # Choose Configuration > AP Config > AP Group > AP Group.
  
  # In the AP group list, click ap-group1. Choose AP > AP System Profile. The AP System Profile page is displayed.
  
  # Click Create. The Create AP System Profile page is displayed. Enter the profile name wlan-spectrum and click OK. On the ap system profile configuration page that is displayed.
  
  # On the Advanced Configuration tab, set related parameters.
  
  # Click Apply. In the dialog box that is displayed, click OK.
2. Create radio profiles.
  
  The following example configures a 2G radio profile. The configuration of a 5G radio profile is similar.
  
  # Choose Configuration > AP Config > AP Group > AP Group.
  
  # In the AP group list, click ap-group1. Choose Radio Management > Radio 0 > 2G Radio Profile. The 2G Radio Profile page is displayed.
  
  # Click Create. On the Create 2G Radio Profile page that is displayed, enter the profile name wlan-radio2g and click OK. The 2G radio profile configuration page is displayed.
  
  # Click Apply. In the dialog box that is displayed, click OK.
3. Create an air scan profile and configure the scan channel set, scan interval, and scan duration.
  # Choose 2G Radio Profile > Air Scan Profile. The Air Scan Profile page is displayed. Click Create. On the Create Air Scan Profile page that is displayed, enter the profile name wlan-airscan and click OK. The air scan profile configuration page is displayed.
  
  # Enable scanning, and configure the scan channel set, scan interval, and scan duration.
  
  # Click Apply. In the dialog box that is displayed, click OK.
4. Enable spectrum analysis on a radio.
  # Click Radio 0. On the Radio 0 Settings(2.4G) page that is displayed, set the radio parameters.
  
  # Click Apply. In the dialog box that is displayed, click OK. The 5G radio configuration is similar and not mentioned here.
Verify the configuration.
1. View AP spectrum on the web platform to learn AP channel interference in deployment sites.
  1. Choose Monitoring > Spectrum Analysis. The Radio List page is displayed.
  2. Select an AP and click Start.
  3. In the AP radio list, click View Drawing in the Operation column. The related spectrum charts are displayed. A maximum of four spectrum charts can be displayed.
  4. Select your desired spectrum chart from the drop-down list box in the upper left corner. You can select Lower or Upper on the spectrum charts of a 5G radio to view spectrum charts of different frequencies.
  5. The Real-Time FFT chart shows that the signal strength of interference is mostly within the range of -80 dBm to -40 dBm. On the Swept Spectrogram chart, click Modify, set the signal strength scope at both ends of the color bar, and click Apply. The Swept Spectrogram chart shows that channel 149 has the most severe interference.
  6. On the Active Devices chart, click . A list of the detected non-Wi-Fi devices is displayed.