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Using Raspberry Pi Zero 2 with Debian. I am tryinfg to understand/decyphir the output using iwconfig. Honing into just the results of my own router I can see using that command gives me my ESSID twice but with different Quality and Signal properties. Why?

BSS 5c:62:8b:ca:2e:9c(on wlan0)
    last seen: 1537.955s [boottime]
    TSF: 0 usec (0d, 00:00:00)
    freq: 2432
    beacon interval: 100 TUs
    capability: ESS Privacy ShortPreamble ShortSlotTime RadioMeasure (0x1431)
    signal: -28.00 dBm
    last seen: 0 ms ago
    SSID: dev
    Supported rates: 1.0* 2.0* 5.5* 11.0* 6.0 9.0 12.0 18.0 
    DS Parameter set: channel 5
    Country: DE Environment: Indoor/Outdoor
        Channels [1 - 13] @ 20 dBm
    TPC report: TX power: 18 dBm
    ERP: <no flags>
    Extended supported rates: 24.0 36.0 48.0 54.0 
    RSN:     * Version: 1
         * Group cipher: CCMP
         * Pairwise ciphers: CCMP
         * Authentication suites: PSK
         * Capabilities: 16-PTKSA-RC 1-GTKSA-RC (0x000c)
    RM enabled capabilities:
        Capabilities: 0x73 0xd0 0x00 0x00 0x0c
            Link Measurement
            Neighbor Report
            Beacon Passive Measurement
            Beacon Active Measurement
            Beacon Table Measurement
            LCI Measurement
            Transmit Stream/Category Measurement
            Triggered Transmit Stream/Category
            FTM Range Report
            Civic Location Measurement
        Nonoperating Channel Max Measurement Duration: 0
        Measurement Pilot Capability: 4
    HT capabilities:
        Capabilities: 0x19ef
            RX LDPC
            HT20/HT40
            SM Power Save disabled
            RX HT20 SGI
            RX HT40 SGI
            TX STBC
            RX STBC 1-stream
            Max AMSDU length: 7935 bytes
            DSSS/CCK HT40
        Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
        Minimum RX AMPDU time spacing: No restriction (0x00)
        HT TX/RX MCS rate indexes supported: 0-15
    HT operation:
         * primary channel: 5
         * secondary channel offset: above
         * STA channel width: any
         * RIFS: 0
         * HT protection: no
         * non-GF present: 0
         * 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:
         * Extended Channel Switching
         * TFS
         * WNM-Sleep Mode
         * TIM Broadcast
         * BSS Transition
         * SSID List
         * Operating Mode Notification
         * Max Number Of MSDUs In A-MSDU is unlimited
    VHT capabilities:
        VHT Capabilities (0x33817992):
            Max MPDU length: 11454
            Supported Channel Width: neither 160 nor 80+80
            RX LDPC
            TX STBC
            SU Beamformer
            SU Beamformee
            RX antenna pattern consistency
            TX antenna pattern consistency
        VHT RX MCS set:
            1 streams: MCS 0-9
            2 streams: MCS 0-9
            3 streams: not supported
            4 streams: not supported
            5 streams: not supported
            6 streams: not supported
            7 streams: not supported
            8 streams: not supported
        VHT RX highest supported: 0 Mbps
        VHT TX MCS set:
            1 streams: MCS 0-9
            2 streams: MCS 0-9
            3 streams: not supported
            4 streams: not supported
            5 streams: not supported
            6 streams: not supported
            7 streams: not supported
            8 streams: not supported
        VHT TX highest supported: 0 Mbps
    VHT operation:
         * channel width: 0 (20 or 40 MHz)
         * center freq segment 1: 7
         * center freq segment 2: 0
         * VHT basic MCS set: 0xfffc
    WMM:     * Parameter version 1
         * u-APSD
         * 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
    WPS:     * Version: 1.0
         * Wi-Fi Protected Setup State: 2 (Configured)
         * Response Type: 3 (AP)
         * UUID: bb16fd7a-0e68-4333-b713-5c628bca2e9a
         * Manufacturer: TP-Link
         * Model: Deco XE75
         * Model Number: Deco XE75
         * Serial Number: 0
         * Primary Device Type: 6-0050f204-1
         * Device name: Whole-home Wi-Fi
         * Config methods:
         * RF Bands: 0x3
         * Version2: 2.0
BSS 5c:62:8b:ca:2e:9d(on wlan0)
    last seen: 1537.955s [boottime]
    TSF: 0 usec (0d, 00:00:00)
    freq: 5180
    beacon interval: 100 TUs
    capability: ESS Privacy SpectrumMgmt ShortSlotTime RadioMeasure (0x1511)
    signal: -37.00 dBm
    last seen: 0 ms ago
    SSID: dev
    Supported rates: 6.0* 9.0 12.0* 18.0 24.0* 36.0 48.0 54.0 
    DS Parameter set: channel 36
    Country: DE Environment: Indoor/Outdoor
        Channels [36 - 36] @ 23 dBm
        Channels [40 - 40] @ 23 dBm
        Channels [44 - 44] @ 23 dBm
        Channels [48 - 48] @ 23 dBm
        Channels [52 - 52] @ 23 dBm
        Channels [56 - 56] @ 23 dBm
        Channels [60 - 60] @ 23 dBm
        Channels [64 - 64] @ 23 dBm
    Power constraint: 3 dB
    TPC report: TX power: 22 dBm
    RSN:     * Version: 1
         * Group cipher: CCMP
         * Pairwise ciphers: CCMP
         * Authentication suites: PSK
         * Capabilities: 16-PTKSA-RC 1-GTKSA-RC (0x000c)
    RM enabled capabilities:
        Capabilities: 0x73 0xd0 0x00 0x00 0x0c
            Link Measurement
            Neighbor Report
            Beacon Passive Measurement
            Beacon Active Measurement
            Beacon Table Measurement
            LCI Measurement
            Transmit Stream/Category Measurement
            Triggered Transmit Stream/Category
            FTM Range Report
            Civic Location Measurement
        Nonoperating Channel Max Measurement Duration: 0
        Measurement Pilot Capability: 4
    HT capabilities:
        Capabilities: 0x9ef
            RX LDPC
            HT20/HT40
            SM Power Save disabled
            RX HT20 SGI
            RX HT40 SGI
            TX STBC
            RX STBC 1-stream
            Max AMSDU length: 7935 bytes
            No DSSS/CCK HT40
        Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
        Minimum RX AMPDU time spacing: No restriction (0x00)
        HT TX/RX MCS rate indexes supported: 0-15
    HT operation:
         * primary channel: 36
         * secondary channel offset: above
         * STA channel width: any
         * 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:
         * Extended Channel Switching
         * TFS
         * WNM-Sleep Mode
         * TIM Broadcast
         * BSS Transition
         * SSID List
         * Operating Mode Notification
         * Max Number Of MSDUs In A-MSDU is unlimited
    VHT capabilities:
        VHT Capabilities (0x3381f9f6):
            Max MPDU length: 11454
            Supported Channel Width: 160 MHz
            RX LDPC
            short GI (80 MHz)
            short GI (160/80+80 MHz)
            TX STBC
            SU Beamformer
            SU Beamformee
            RX antenna pattern consistency
            TX antenna pattern consistency
        VHT RX MCS set:
            1 streams: MCS 0-9
            2 streams: MCS 0-9
            3 streams: not supported
            4 streams: not supported
            5 streams: not supported
            6 streams: not supported
            7 streams: not supported
            8 streams: not supported
        VHT RX highest supported: 0 Mbps
        VHT TX MCS set:
            1 streams: MCS 0-9
            2 streams: MCS 0-9
            3 streams: not supported
            4 streams: not supported
            5 streams: not supported
            6 streams: not supported
            7 streams: not supported
            8 streams: not supported
        VHT TX highest supported: 0 Mbps
    VHT operation:
         * channel width: 1 (80 MHz)
         * center freq segment 1: 42
         * center freq segment 2: 50
         * VHT basic MCS set: 0xfffc
    Transmit Power Envelope:
         * Local Maximum Transmit Power For 20 MHz: 23 dBm
         * Local Maximum Transmit Power For 40 MHz: 23 dBm
         * Local Maximum Transmit Power For 80 MHz: 23 dBm
         * Local Maximum Transmit Power For 160/80+80 MHz: 23 dBm
    WMM:     * Parameter version 1
         * u-APSD
         * 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
    WPS:     * Version: 1.0
         * Wi-Fi Protected Setup State: 2 (Configured)
         * Response Type: 3 (AP)
         * UUID: bb16fd7a-0e68-4333-b713-5c628bca2e9a
         * Manufacturer: TP-Link
         * Model: Deco XE75
         * Model Number: Deco XE75
         * Serial Number: 0
         * Primary Device Type: 6-0050f204-1
         * Device name: Whole-home Wi-Fi
         * Config methods:
         * RF Bands: 0x3
         * Version2: 2.0
Andrew Simpson
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1 Answers1

5

Since they're on the same band, it looks like those are two different access points – with different BSSIDs aka MAC addresses – offering access to the same network.

It is standard for multiple APs within range of each other to be set up to offer the same ESSID – e.g. at universities or other large venues – although they ought to lead to the same LAN (same subnet) whenever that's done. (Devices will automatically roam between APs that offer the same ESSID, so if they actually provide access to separate yet identically-named networks, then that's a misconfiguration, as devices will lose all TCP connections when they roam between those APs.)

The RSSI signal strength suggests that the first one is probably your neighbor's, or maybe your own "WiFi extender" in a different floor, etc.

I would recommend replacing iwlist/iwconfig with the more modern iw wlan0 scan. It uses the standard Linux nl80211 API instead of the obsolete WEXT API, but more usefully, it knows how to decode all of the newer Information Elements ('IE's) that the old iwconfig just gives up on.

grawity
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