We have created IP-mesh using 802.11s (mesh11sd) with help of 3 routers. Each router is connected to RPI via ethernet cable through which we are sending broadcast packets and other RPIs are receiving. On careful observation we found that RPIs connected to the routers are receiving multiple packets of same sequence number.
Can you please help us with this abnormal behaviour or may be the possible cause of data repetition?
802.11s is a layer-2 mesh.
Could it be you see this because you have disabled STP? (Purely speculating here)
Have you considered using batman-adv on top of 11s if you need/want to have a layer-2 mesh, or if you instead want to have a layer-3, then using olsr2 or Babel?
So you have the 3 mesh nodes connected together with ethernet cables?
An 802.11s mesh is a WIRELESS backhaul. You have also connected with ethernet.
This will give you a bridge loop. Your broadcast packets will go via the mesh backhaul AND the ethernet.
This is not abnormal behaviour, it is a bad and pointless configuration.
What is it you are trying to achieve?
As you said in the first line,
802.11s IS a layer-2 mesh
..... Batman-adv is not needed for a wireless mesh backhaul.
I know that 11s can be used on it's own if it's forwarding mode is enabled, but it does not scale that well, right? Wasn't there a limitation on ~ 30 nodes? And you still have to deal with STP? Right? (Or does have 11s an buildin Feature to choose a path fast when the topology changes?)
I have never really thought about it... But there is an actual "routing" protocol build in 11s. I just find it confusing that's called routing but it does path based forwarding. However here is the https://datatracker.ietf.org/doc/html/rfc3561
Site node: like 7 years ago I tried to use plain 11s at home and as I recall I've run into STP issues why I settled in the end by using batman-adv because of its loop avoidance feature. 
There is probably a need for a separate thread for discussing 802.11s but for the benefit of all I will attempt to answer questions and pose others here for now.
I don't know where you got the idea that it does not scale well, but it is probably an historic misconception (see my later comments).
No, there never has been. There is a limit of 255 direct peer connections allowed per node.
A direct peer connection means a "single hop" to an immediate neighbour.
This means a node can have up to 255 directly linked peers. In typical dense 3D mesh I would expect no more than 10 or so directly connected peers, so 255 is way more than would normally be needed.
Yes, 802.11s has a "built in feature". Normally STP is not required, unless you have inter-node links by some other medium (eg ethernet), in addition to the mesh backhaul.
It is normally referred to as mac-routing (working at layer 2), to differentiate from ip-routing.
The mac-routing protocal is known as Hybrid Wireless Mesh Protocol (HWMP)
See:
Seven years ago, 802.11s support in OpenWrt was very incomplete. It was impossible to configure mesh nodes fully using the standard OpenWrt uci config, and encryption of the mesh links was experimental and at best was flaky and at worst would crash the wireless drivers.
This has long been fixed. The mesh11sd package now handles dynamic mesh parameter setting not possible in the standard wireless config.
You can see an overview here:
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Thanks for your reply,
Could you please help me to Tune STP Timers? What will be the best values of below parameters'?
- hello
- max age
- forward delay
I am greeting high latency in network post enable with default values.
Why do you think you need STP?
You have not answered the questions I asked over a week ago....
As we have IP-mesh on Radio 1 and each router is connected to RPI via ethernet cable. We are sending broadcast packets on each RPI and other RPIs are receiving.
But we found that RPIs are receiving multiple duplicate packets instead of receiving exact count which we broadcasting in network.
So, we want to stop these duplicate repeated packets.
What is an IP-mesh?
An 802.11s mesh is purely a layer 2, mac-routing wireless backhaul that can carry all sorts of traffic. It neither knows nor cares about any IP packets it may carry.
So you have your routers connected by ethernet?
Why do you think you need a mesh backhaul?
I pretty much asked these questions earlier and you have ignored them......
What are you trying to achieve?