Dual band AP mode?

#1

I am yet to receive my RockPi E board - my main use case is to set it up as a wireless router + firewall device, I have ordered 5GHz variant that has RTL8821CU chip.

I was wondering I will be able to use the wlan chip in dual-band AP mode with hostapd - i.e. simultaneous 2.4 GHz and 5GHz dual channel AP.

According to output of iw list I was able to find somewhere on internet it seems like “interface combinations are not supported” - this will terribly affect my intended use case - I do not want to use separate USB adapter for the other band.

Can someone who has the device share the iw list output and confirm if this indeed is a case ?

Thanks :slight_smile:

#2

This is from my Rocpi E eng. Sample, kernel 5.9.0-rc8 . Note there are several RTL8821CU sources around the internet, but basically the same port… But I would not rely solely on this output:.
What I can say is that RTL8821CU is superior to most of the broadcom/cypress i have tested so far.

ubuntu@rockpie:~$ sudo iw list
[sudo] password for ubuntu: 
Wiphy phy0
	max # scan SSIDs: 9
	max scan IEs length: 2304 bytes
	max # sched scan SSIDs: 0
	max # match sets: 0
	max # scan plans: 1
	max scan plan interval: -1
	max scan plan iterations: 0
	Retry short limit: 7
	Retry long limit: 4
	Coverage class: 0 (up to 0m)
	Supported Ciphers:
		* WEP40 (00-0f-ac:1)
		* WEP104 (00-0f-ac:5)
		* TKIP (00-0f-ac:2)
		* CCMP-128 (00-0f-ac:4)
	Available Antennas: TX 0 RX 0
	Supported interface modes:
		 * IBSS
		 * managed
		 * AP
		 * monitor
		 * P2P-client
		 * P2P-GO
	Band 1:
		Capabilities: 0x1962
			HT20/HT40
			Static SM Power Save
			RX HT20 SGI
			RX HT40 SGI
			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: 16 usec (0x07)
		HT Max RX data rate: 150 Mbps
		HT TX/RX MCS rate indexes supported: 0-7
		Bitrates (non-HT):
			* 1.0 Mbps
			* 2.0 Mbps
			* 5.5 Mbps
			* 11.0 Mbps
			* 6.0 Mbps
			* 9.0 Mbps
			* 12.0 Mbps
			* 18.0 Mbps
			* 24.0 Mbps
			* 36.0 Mbps
			* 48.0 Mbps
			* 54.0 Mbps
		Frequencies:
			* 2412 MHz [1] (20.0 dBm)
			* 2417 MHz [2] (20.0 dBm)
			* 2422 MHz [3] (20.0 dBm)
			* 2427 MHz [4] (20.0 dBm)
			* 2432 MHz [5] (20.0 dBm)
			* 2437 MHz [6] (20.0 dBm)
			* 2442 MHz [7] (20.0 dBm)
			* 2447 MHz [8] (20.0 dBm)
			* 2452 MHz [9] (20.0 dBm)
			* 2457 MHz [10] (20.0 dBm)
			* 2462 MHz [11] (20.0 dBm)
			* 2467 MHz [12] (20.0 dBm) (no IR)
			* 2472 MHz [13] (20.0 dBm) (no IR)
			* 2484 MHz [14] (disabled)
	Band 2:
		Capabilities: 0x1862
			HT20/HT40
			Static SM Power Save
			RX HT20 SGI
			RX HT40 SGI
			No RX STBC
			Max AMSDU length: 7935 bytes
			DSSS/CCK HT40
		Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
		Minimum RX AMPDU time spacing: 16 usec (0x07)
		HT Max RX data rate: 150 Mbps
		HT TX/RX MCS rate indexes supported: 0-7
		VHT Capabilities (0x03c00122):
			Max MPDU length: 11454
			Supported Channel Width: neither 160 nor 80+80
			short GI (80 MHz)
			+HTC-VHT
		VHT RX MCS set:
			1 streams: MCS 0-9
			2 streams: not supported
			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: 434 Mbps
		VHT TX MCS set:
			1 streams: MCS 0-9
			2 streams: not supported
			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: 434 Mbps
		Bitrates (non-HT):
			* 6.0 Mbps
			* 9.0 Mbps
			* 12.0 Mbps
			* 18.0 Mbps
			* 24.0 Mbps
			* 36.0 Mbps
			* 48.0 Mbps
			* 54.0 Mbps
		Frequencies:
			* 5180 MHz [36] (17.0 dBm)
			* 5200 MHz [40] (17.0 dBm)
			* 5220 MHz [44] (17.0 dBm)
			* 5240 MHz [48] (17.0 dBm)
			* 5260 MHz [52] (24.0 dBm) (no IR, radar detection)
			* 5280 MHz [56] (24.0 dBm) (no IR, radar detection)
			* 5300 MHz [60] (24.0 dBm) (no IR, radar detection)
			* 5320 MHz [64] (24.0 dBm) (no IR, radar detection)
			* 5500 MHz [100] (24.0 dBm) (no IR, radar detection)
			* 5520 MHz [104] (24.0 dBm) (no IR, radar detection)
			* 5540 MHz [108] (24.0 dBm) (no IR, radar detection)
			* 5560 MHz [112] (24.0 dBm) (no IR, radar detection)
			* 5580 MHz [116] (24.0 dBm) (no IR, radar detection)
			* 5600 MHz [120] (24.0 dBm) (no IR, radar detection)
			* 5620 MHz [124] (24.0 dBm) (no IR, radar detection)
			* 5640 MHz [128] (24.0 dBm) (no IR, radar detection)
			* 5660 MHz [132] (24.0 dBm) (no IR, radar detection)
			* 5680 MHz [136] (24.0 dBm) (no IR, radar detection)
			* 5700 MHz [140] (24.0 dBm) (no IR, radar detection)
			* 5720 MHz [144] (disabled)
			* 5745 MHz [149] (30.0 dBm)
			* 5765 MHz [153] (30.0 dBm)
			* 5785 MHz [157] (30.0 dBm)
			* 5805 MHz [161] (30.0 dBm)
			* 5825 MHz [165] (30.0 dBm)
			* 5845 MHz [169] (disabled)
			* 5865 MHz [173] (disabled)
			* 5885 MHz [177] (disabled)
	Supported commands:
		 * new_interface
		 * set_interface
		 * new_key
		 * start_ap
		 * new_station
		 * set_bss
		 * join_ibss
		 * set_pmksa
		 * del_pmksa
		 * flush_pmksa
		 * remain_on_channel
		 * frame
		 * set_channel
		 * connect
		 * disconnect
	Supported TX frame types:
		 * IBSS: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
		 * managed: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
		 * AP: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
		 * AP/VLAN: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
		 * P2P-client: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
		 * P2P-GO: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
	Supported RX frame types:
		 * IBSS: 0xd0
		 * managed: 0x40 0xd0
		 * AP: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
		 * AP/VLAN: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
		 * P2P-client: 0x40 0xd0
		 * P2P-GO: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
	WoWLAN support:
		 * wake up on anything (device continues operating normally)
	software interface modes (can always be added):
		 * monitor
	interface combinations are not supported
	Device supports scan flush.
	Supported extended features:
1 Like
#3

There is no other way. All dual-band routers have separate radio for 2.4 and 5Ghz. If you have one device - you can choose where to have AP, but you can’t run it simultaneously.

1 Like
#4

It’s my fault - I didn’t research on the chipset prior. It’s alright. I have limited use of 2.4GHz band and I can probably use the USB adapter for that.