Fast Roaming 802.11r - Multiple SSIDs = different mobility domains?

hnyman · March 24, 2024, 5:58am

Here $(echo "$ssid" | md5sum | head -c 4)

openwrt/openwrt/blob/8753022aeae14eaee02e0c1e59244c5b36e454db/package/network/config/wifi-scripts/files/lib/netifd/hostapd.sh#L918


      
          		append bss_conf "wpa_disable_eapol_key_retries=$wpa_disable_eapol_key_retries" "$N"
          
          		hostapd_append_wpa_key_mgmt
          		[ -n "$wpa_key_mgmt" ] && append bss_conf "wpa_key_mgmt=$wpa_key_mgmt" "$N"
          	fi
          
          	if [ "$wpa" -ge "2" ]; then
          		if [ "$ieee80211r" -gt "0" ]; then
          			json_get_vars mobility_domain ft_psk_generate_local ft_over_ds reassociation_deadline
          
          			set_default mobility_domain "$(echo "$ssid" | md5sum | head -c 4)"
          			set_default ft_over_ds 0
          			set_default reassociation_deadline 1000
          
          			case "$auth_type" in
          				psk)
          					set_default ft_psk_generate_local 1
          				;;
          				*)
          					set_default ft_psk_generate_local 0
          				;;

How is the value different?
One possible reason is bigendian/littleendian byte order difference meaning 1234 vs. 3412. (Is it seen as a string or hexadecimal number where byte order depends on CPU?)

You might manually set it into a byte-symmetric value like 3737 or 6868 in all devices.