Re: WiFi chips/drivers supporting IBSS/802.11s

[Sven Eckelmann <sven@narfation.org>]

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On Thursday, 14 May 2020 10:17:07 CEST Maksim Iushchenko wrote:
> Hello,

Please add subjects to your mails. Next time, I will just reject this
kind of mail.

> I am creating a Wi-Fi ad-hoc network based on batman-adv. I read that
> batman-adv is able to work with any types of interfaces, but I still
> have a question related to ad-hoc networking. Will Wi-Fi ad-hoc
> network (based on batman-adv) work if Wi-Fi chip does not support
> 802.11s standard?

Hu? You are mixing stuff up. There is traditional IBSS (often called adhoc) 
and then there is 802.11s (meshpoint interfaces with and without an integrated 
mesh protocol).

> Unfortunately, there is no mention of ad-hoc mode support in
> documentation of many Wi-Fi chips.
> 
> How to check if a Wi-Fi chip is suited to be used to create a Wi-Fi
> ad-hoc network based on batman-adv?

Check for "valid interface combinations" in `iw phy`. Here for example from an 
QCA955x (when I remember correctly)

        valid interface combinations:
                 * #{ managed } <= 2048, #{ AP, mesh point } <= 8, #{ P2P-client, P2P-GO } <= 1, #{ IBSS } <= 1,
                   total <= 2048, #channels <= 1, STA/AP BI must match, radar detect widths: { 20 MHz (no HT), 20 MHz, 40 MHz }

You can see here that it supports a limited number of mesh points interfaces 
(802.11s) together with AP interfaces. It also supports IBSS (adhoc). Just
keep in mind that there are a lot of broken wifi drivers and wifi firmwares
out there which claim to support IBSS/802.11s but fail to reliably receive
or transmit over these interface types.

> For example, is ATWILC3000-MR110CA an appropriate chip to build a
> Wi-Fi ad-hoc network based on batman-adv? Or maybe you could suggest
> any another Wi-Fi chips?

No idea what it is.

ath9k based chips work good. ath10k work also with ath10k firmware in 802.11s 
mode. Just make sure that you disable mesh_fwding when you want to run 
batman-adv over an meshpoint interface.

Kind regards,
	Sven

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