Should AP advertise as HT20/40 if it can only run HT20?

[Ben Greear]

We configured an AP to run on channel 6, HT40+.

But, due to scan results, it decided it could only run HT20 due to
overlapping BSS.

The scan results show it as having HT20/40 capability but
no secondary channel.

Is this expected?  I was thinking it might should not be advertising
the HT40.  We are running local patches, possibly we messed up something.

Thanks,
Ben



BSS 04:f0:21:7d:cc:36(on sta13) -- associated
     TSF: 0 usec (0d, 00:00:00)
     freq: 2437
     beacon interval: 240 TUs
     capability: ESS ShortSlotTime (0x0401)
     signal: -18.00 dBm
     last seen: 1 ms ago
     Information elements from Probe Response frame:
     SSID: brenttest-10k
     Supported rates: 1.0* 2.0* 5.5* 11.0* 6.0 9.0 12.0 18.0
     DS Parameter set: channel 6
     ERP: Barker_Preamble_Mode
     Extended supported rates: 24.0 36.0 48.0 54.0
     HT capabilities:
         Capabilities: 0x6e
             HT20/HT40
             SM Power Save disabled
             RX HT20 SGI
             RX HT40 SGI
             No RX STBC
             Max AMSDU length: 3839 bytes
             No DSSS/CCK HT40
         Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
         Minimum RX AMPDU time spacing: 8 usec (0x06)
         HT TX/RX MCS rate indexes supported: 0-23
     HT operation:
          * primary channel: 6
          * secondary channel offset: no secondary
          * STA channel width: 20 MHz
          * RIFS: 0
          * HT protection: no
          * non-GF present: 1
          * OBSS non-GF present: 0
          * dual beacon: 0
          * dual CTS protection: 0
          * STBC beacon: 0
          * L-SIG TXOP Prot: 0
          * PCO active: 0
          * PCO phase: 0
     Extended capabilities: SSID List, 6
     WMM:     * Parameter version 1
          * BE: CW 15-1023, AIFSN 3
          * BK: CW 15-1023, AIFSN 7
          * VI: CW 7-15, AIFSN 2, TXOP 3008 usec
          * VO: CW 3-7, AIFSN 2, TXOP 1504 usec
-- 
Ben Greear <greearb at candelatech.com>
Candela Technologies Inc  http://www.candelatech.com