Cisco Receiver Start of Packet

Receiver start of packet detection threshold

A receiver start of packet (Rx SOP) detection threshold is a wireless radio configuration setting that

  • determines the Wi-Fi signal level (measured in dBm) at which an APs radio demodulates and decodes a received packet

  • affects radio sensitivity and the effective size of the receiver cell, and

  • influences how clients are distributed across APs within a wireless network.

Rx SOP is used to address clients with weak RF links, sticky clients, and to support client load balancing across APs. Rx SOP helps optimize network performance in high-density deployments, such as stadiums and auditoriums. In these environments, APs need to prioritize the nearest and strongest clients.

Restrictions for Rx SOP

  • Rx SOP configuration does not apply to the third radio module pluggable on Cisco Aironet 3600 Series APs.

  • Rx SOP configurations are supported only in Local, FlexConnect, Bridge, and Flex+Bridge modes.

  • Rx SOP configurations are not supported in the FlexConnect+PPPoE, FlexConnect+PPPoE-wIPS, and FlexConnect+OEAP submodes.

Permitted range for the Rx SOP threshold

This table shows the allowed Rx SOP (Receiver Start of Packet) threshold settings.

  • It is for different radio bands and threshold levels.

Table 1. Rx SOP Threshold

Radio Band

Threshold High

Threshold Medium

Threshold Low

2.4 GHz

-79 dBm

-82 dBm

-85 dBm

5 GHz

-76 dBm

-78 dBm

-80 dBm

Known behavior

Regardless of the radio mode, the controller sets the radio with the specified RX-SOP value. The AP then decides whether to use this value.

  • For the XOR radio (Slot 0), when the AP is in monitor mode, the RX-SOP value sent to the AP depends on the frequency band used before switching to monitor mode. If the radio operated in the 2.4 GHz band, the RX-SOP parameters are selected from the 2.4 GHz RF profile or the default RF profile. If it operated in the 5 GHz band, the RX-SOP parameters are chosen from the 5 GHz RF profile or the default RF profile configured for the AP.

Configure Rx SOP (CLI)

Adjust the Rx SOP threshold for high-density Wi-Fi environments.

Procedure

Step 1

Enter the global configuration mode.

Example:


DeviceDevice# configure terminal

Step 2

Configure the 802.11bg or 802.11a radio Rx SOP threshold.

Example:


DeviceDevice(config)# ap dot11 {24ghz | 5ghz} rx-sop threshold {auto | custom | high | low | medium}

Step 3

Return to the privileged EXEC mode.

Example:

Device# end

Step 4

Display the 802.11bg or 802.11a high-density parameters.

Example:


DeviceDevice# show ap dot11 {24ghz | 5ghz} high-density

Step 5

Display the summary of all the connected Cisco APs.

Example:


DeviceDevice# show ap summary

Customize RF profile (CLI)

Customize 802.11 RF profile parameters.

Procedure

Step 1

Enter the global configuration mode.

Example:


DeviceDevice# configure terminal

Step 2

Configure the 802.11bg, 802.11a or 802.11 6-GHz high-density parameters.

Example:


DeviceDevice(config-rf-profile)# high-density rx-sop threshold {auto | custom | high | low | medium}

Step 3

Display the summary of all the connected Cisco APs.

Example:


DeviceDevice# show ap summary

Step 4

Return to the privileged EXEC mode.

Example:

Device# end