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Spirent TestCenter: WiFi - Unable to associate at 160MHz using C50-KIT-11AX-1-V2 (NIC-71)

Symptoms

enlightenedYou may want to check first: FAQ19674 - Spirent TestCenter: WiFi - How to associate at 160Mhz?


The clients are being associated with channel bandwidth as 80 MHz even though the channel bandwidth on the port is set to 160 MHz and the AP is set to 160MHz. This behavior is observed for each of the above test scenarios with different spatial streams
  1. STC PORT:
 
  1. AP side:

 
 


 
Environment
 
  • Spirent TestCenter
  • WiFi
  • 80Mhz
  • 160Mhz
  • C50-KIT-11AX-1-V2 (NIC-71)
  • C50-KIT-11AX-6
Explanation/Resolution

From EE team and Qualcomm document, got some information:
 
  • NIC-71 hardware (C50-KIT-11AX-1-V2) can operate only 80MHz, so only 2 radio mode can operate with 160/80+80 4x4.
  • Check in Qualcomm document, found that IPQ check for ext_nss_cap ie in beacon frame to operate 160 MHz.

Same test result were done as below:
  • Test result with APs
    • Test with ASUS_AX11000 AP which has has ext_nss_cap the IPQ can associate with 160 MHz. (Pass)
    • Test with Netgear AP(RAX120) which does not have ext_nss_cap the IPQ cannot associate with 160 MHz. (Fail)
    • Test with AP Emulator which enable ext_nss_cap the IPQ can associate with 160 MHz. (Pass)
    • Test with AP Emulator which disable ext_nss_cap the IPQ cannot associate with 160 MHz. (Fail)

You can check on the beacon frame of the AP if it has the capability as in figure below. (Under VHT Supported MCS Set -> Tx MCS Map: 0xffaa -> Extended NSS BW CAPABLE :__________ ) This could say Capable / not capable
 

 


enlightened  We tried the RAX120 AP (one of the AP railing to associate with NIC-71 chassis) but this time with C50-KIT-11AX-6, and this chassis is able to associate at 160MHz even the AP has Extended NSS BW Capable: Not Capable:



 
Root Cause
 
  • Hardware Limitation on NIC-71 - C50-KIT-11AX-1-V2, this hardware does need the AP to support external NSS signaling to associate with the AP with 160MHz bandwidth.
 

Product : Wireless,WiFi,Spirent TestCenter,WiFi,Wireless,C50R_CONTROLLER