Hi Everybody,
I'm running BATMAN v 2019.2 with ath10k on OpenWRT. The particular router I'm using has two interfaces, 2.4 GHz and 5GHz. With each router using single interface (e.g. 2.4 GHz), it works fine. When I add a second interface (e.g. 5GHz), it sometimes hangs.
I know that BATMAN is expected to alternate between the two interfaces, but that doesn't seem to be working. As you probably know, using two interfaces should dramatically improve throughput if you need to make a hop through another mesh node.
To verify this is the problem, I did a test where I ran three routers, 2.4G <> Dual (2.4G & 5G) <> 5G. I would try to ping between the two routers that were using just a single interface. Obviously, that must hop through the dual radio router. The dual radio router has both interfaces on the bat0 master, and batctl reports they're both active.
The system would sometimes lose link, although batctl would report getting neighbor messages. Even using the batctl ping function doesn't get through. I can see traffic flowing on both the 2.4 GHz and 5GHz interfaces.
I'm happy to provide lots of configuration detail, but I thought I'd start with a high level description in case this is a known problem.
Any assistance is appreciated. Thank you,
--Joe
On Thursday, April 8, 2021 7:56:29 AM CEST joe@careyhome.org wrote:
Hi Everybody,
I'm running BATMAN v 2019.2 with ath10k on OpenWRT. The particular router I'm using has two interfaces, 2.4 GHz and 5GHz. With each router using single interface (e.g. 2.4 GHz), it works fine. When I add a second interface (e.g. 5GHz), it sometimes hangs.
I know that BATMAN is expected to alternate between the two interfaces, but that doesn't seem to be working. As you probably know, using two interfaces should dramatically improve throughput if you need to make a hop through another mesh node.
To verify this is the problem, I did a test where I ran three routers, 2.4G <> Dual (2.4G & 5G) <> 5G. I would try to ping between the two routers that were using just a single interface. Obviously, that must hop through the dual radio router. The dual radio router has both interfaces on the bat0 master, and batctl reports they're both active.
The system would sometimes lose link, although batctl would report getting neighbor messages. Even using the batctl ping function doesn't get through. I can see traffic flowing on both the 2.4 GHz and 5GHz interfaces.
I'm happy to provide lots of configuration detail, but I thought I'd start with a high level description in case this is a known problem.
Any assistance is appreciated. Thank you,
--Joe
Hi Joe,
I'd expect your setup to work. Could you try to run "batctl ping" between the nodes, maybe also on the intermediate links? If you see that it's failing too, could you set up some IPv4 addresses (or use IPv6 link local addresses) on your ad-hoc/mesh interfaces, and try to ping to the next hop? I suspect that something is off with the wifi driver, i.e. broadcasts are still working but unicast pings are dropped.
Cheers, Simon
On Fri, Apr 09, 2021 at 12:17:36PM +0200, Simon Wunderlich wrote:
On Thursday, April 8, 2021 7:56:29 AM CEST joe@careyhome.org wrote:
Hi Everybody,
I'm running BATMAN v 2019.2 with ath10k on OpenWRT. The particular router I'm using has two interfaces, 2.4 GHz and 5GHz. With each router using single interface (e.g. 2.4 GHz), it works fine. When I add a second interface (e.g. 5GHz), it sometimes hangs.
One more note: ath10k firmware refuses to provide an expected throughput for the wifi link.
The fallback to an estimate which uses the raw tx bitrate was added not that long ago in batman-adv v2020.0:
https://www.open-mesh.org/news/95
I'm wondering if you might have very low throughput values in batman-adv and if that might lead to issues with interface alternating.
Also, would be interesting to know if you have the same issues when using BATMAN IV, which mainly uses a packetloss based metric.
Regards, Linus
Linus and Simon,
Thank you for your responses.
I did try "batctl ping" and the adjacent device was unreachable. I could see it with "batctl n". I did not try a simple IPv6 link local ping. However, I could see it using "iw dev mesh_5g station dump"
I agree that it feels like a problem with ath10k reporting the data rate incorrectly (or not at all).
I am going to try upgrading to the latest release, but it will be a few days. I'll let you know how it goes.
Thanks again,
--Joe
On Saturday, April 10, 2021 2:39:53 AM CEST joe@careyhome.org wrote:
Linus and Simon,
Thank you for your responses.
I did try "batctl ping" and the adjacent device was unreachable. I could see it with "batctl n". I did not try a simple IPv6 link local ping. However, I could see it using "iw dev mesh_5g station dump"
I agree that it feels like a problem with ath10k reporting the data rate incorrectly (or not at all).
I am going to try upgrading to the latest release, but it will be a few days. I'll let you know how it goes.
Thanks again,
--Joe
Sounds great! You may want to take some more measures to find out if the packets are actually getting transferred, e.g. doing tcpdump on both the sending and receiving side. If you see packets sent but not received on the other side, you know that it's a driver issue. Also "tcpdump" helps. For ath10k, you may want to try 11s/mesh mode with TTL=1, while with ath10k-ct you may prefer IBSS mode (I think that wasn't mentioned in your first mail).
Cheers, Simon
On Tuesday, 13 April 2021 13:53:16 CEST Simon Wunderlich wrote: [...]
Also "tcpdump" helps. For ath10k, you may want to try 11s/mesh mode with TTL=1, while with ath10k-ct you may prefer IBSS mode (I think that wasn't mentioned in your first mail).
Please avoid the ath10k-ct firmware. And for ath10k, please make sure to set mesh_fwding=0 on the mesh(point) interface.
Kind regards, Sven
Am Di., 13. Apr. 2021 um 14:03 Uhr schrieb Sven Eckelmann sven@narfation.org:
Please avoid the ath10k-ct firmware. And for ath10k, please make sure to set mesh_fwding=0 on the mesh(point) interface.
This is true for Wave-1 chipsets (QCA98xx) but Wave-2 Chipsets (QCA99xx) needs the ath10-ct firmware to get 802.11s running.
Haven't got stable results with BATMAN V in a home mesh environment. Nodes could ping each other via batctl ping but IP ping often failed. Maybe some issues of mesh routing when many routes to the same target had nearly the same link speeds? I'm using a dense setup of many routers, so every router is seeing at least 2-3 neighbours. The preferred routes (marked with a [*] in batctl o ?) switched quite often. How is the BATMAN V metric affected by link quality & hop count?
Regards, Andi
b.a.t.m.a.n@lists.open-mesh.org
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Andi Depressivum -
joe＠careyhome.org -
Linus Lüssing -
Simon Wunderlich -
Sven Eckelmann