Cisco Receiver Start of Packet

Information About Receiver Start of Packet Detection Threshold

The Receiver Start of Packet (Rx SOP) Detection Threshold feature determines the Wi-Fi signal level in dBm at which an access point's radio demodulates and decodes a packet. As the Wi-Fi level increases, the radio sensitivity decreases and the receiver cell size becomes smaller. Reduction of the cell size affects the distribution of clients in the network.

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

Restrictions for Rx SOP

  • Rx SOP configuration is not applicable to the third radio module pluggable on Cisco Aironet 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.

The following table shows the permitted range for the Rx SOP threshold.

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

Configuring Rx SOP (CLI)

Procedure

  Command or Action Purpose

Step 1

configure terminal

Example:


Device# configure terminal

Enters global configuration mode.

Step 2

ap dot11 {24ghz | 5ghz} rx-sop threshold {auto | custom | high | low | medium}

Example:

Device(config)# ap dot11 5ghz rx-sop threshold high

Configures the 802.11bg/802.11a radio Rx SOP threshold.

Step 3

end

Returns to privileged EXEC mode.

Step 4

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

Example:

Device# show ap dot11 5ghz high-density

Displays the 802.11bg/802.11a high-density parameters.

Step 5

show ap summary

Example:

Device# show ap summary

Displays a summary of all the connected Cisco APs.

Customizing RF Profile (CLI)

Procedure

  Command or Action Purpose

Step 1

configure terminal

Example:


Device# configure terminal

Enters global configuration mode.

Step 2

ap dot11 {24ghz | 5ghz } rf-profile profile-name

Example:

Device(config)# ap dot11 24ghz rf-profile AHS_2.4ghz

Configures the 802.11a and 11b parameters.

Step 3

high-density rx-sop threshold {auto | custom | high | low | medium}

Example:

Device(config-rf-profile)# high-density rx-sop threshold high

Configures the 802.11bg, 802.11a high-density parameters.

Step 4

show ap summary

Example:

Device# show ap summary

Displays a summary of all the connected Cisco APs.

Step 5

end

Returns to privileged EXEC mode.

Note

 

  • Irrespective of radio mode, the controller configures the radio with configured RX-SOP value. The AP determines whether to use the configured RX-SOP value.

  • For the XOR radio (Slot 0), when the AP is in monitor mode the RX-SOP value that gets pushed to AP depends on the band it was operating before moving to monitor mode (basically if radio operating band is 24g then RX-SOP params picked from 24GHz RF profile (or default rf-profile). If it was in 5g then RX-SOP params picked from 5GHz RF profile (or default rf-profile) configured for the AP).