Re: Restarting MeshPoint – seeking advice on routing for crisis/disaster scenarios

[Simon Wunderlich <sw@simonwunderlich.de>]

Hi Valent,

thank you for your interest and sorry for the late reply. The time before 
Christmas is usually a bit hectic ...

I would suggest to look into the "gluon" Freifunk Firmware [1], including the 
batman-adv parameters made there. There are setups with a couple of hundred 
nodes, although some sparsely connected over cities. Those setups have been 
used and tested for a long time on different types of hardware.

A few general suggestions for tuning for those scenarios are:

* set up a high multicast rate, at least 12 MBit/s, perhaps 24 or more. You 
will trade scalability with range

* choose a higher than default OGM interval, e.g. 5 seconds instead of 1 
second. This makes batman-adv reaction time slower, but helps scaling with 
many nodes. Each node would repeat any other nodes OGM messages, which results 
in O(N^2) OGM messages per interval.

* if you don't need encryption (SAE), turn it off. SAE by default does a peer-
to-peer handshake, which can kill a dense network with many participants in 
one place, if everyone wants to handshake with everyone else at the same time.

There are a few more things (e.g. reducing basic rates) which you may find in 
the gluon firmware and other places. 

As you can see, some of those suggestions are more Wi-Fi layer specific than 
batman-adv specific, and would help with other protocols (e.g. babel) as well. 
From my experience with network simulators/emulators, you may verify protocol 
specific behavior (e.g. number of messages, failover time) to some extent. But 
testing Wi-Fi specific scaling effects like failing SAE handshakes, effects of 
multicast rates, etc is rather hard - even if you use emulators based on 
mac80211_hwsim or so which partially emulate 802.11. For those experiments, 
it's best to actually set up 10-20 devices ...

Cheers,
        Simon

[1] https://gluon.readthedocs.io/en/latest/

On Saturday, December 20, 2025 11:43:20 PM Central European Standard Time 
Valent@MeshPoint wrote:
> Hello,
> 
> I wanted to follow up on my previous message. I did not see any replies,
> so I hope it is ok to share one concrete finding from recent testing in
> case it helps the discussion.
> 
> To move beyond purely theoretical arguments, I have been running large
> scale tests using meshnet lab
> https://github.com/mwarning/meshnet-lab
> 
> The main reason for choosing it is that it allows replaying real world
> community network topologies, including Freifunk graphs, instead of
> relying on synthetic grids or ideal meshes. This makes it easier to
> observe behaviour under sparse, asymmetric, and imperfect conditions
> that are closer to what actually gets deployed.
> 
> One interesting observation so far is that results can vary
> significantly depending on how nodes are brought up and how control
> plane load interacts with the topology. In other words, the same
> protocol on the same topology can behave very differently depending on
> timing, churn, and scale effects, even when the underlying links are
> identical. This was not obvious to me before testing at this scale.
> 
> I am curious whether others here have used meshnet lab or similar
> namespace based emulation tools for BATMAN adv testing, and if so,
> whether your observations matched real deployments closely, or if there
> are known caveats when interpreting the results.
> 
> Any feedback or pointers would be appreciated.
> 
> Best regards,
> Valent
> 
> 
> ------ Original Message ------
> 
> >From "Valent Turkovic" <valent@meshpointone.com>
> 
> To b.a.t.m.a.n@lists.open-mesh.org
> Date 16.12.2025. 16:37:01
> Subject Restarting MeshPoint – seeking advice on routing for
> crisis/disaster scenarios
> 
> >Hi everyone,
> >
> >My name is Valent Turkovic.
> >
> >Between 2015 and 2018 I ran the MeshPoint project – a simple, rugged Wi-Fi
> >hotspot designed to work in very tough conditions.
> >
> >During the refugee crisis in Croatia we deployed these devices in camps and
> >transit centers, providing internet connectivity for humanitarian
> >organizations such as the Red Cross, UNICEF, IOM, Greenpeace, and many
> >smaller NGOs. Through these deployments, more than 500,000 people were
> >able to stay connected. The same system was also used in flood response
> >and other emergency situations. The project received the “Best
> >Humanitarian Tech of the Year” award at The Europas in 2016.
> >
> >Unfortunately, financial constraints forced me to pause the project after
> >2018. It was entirely self-funded, and the prolonged stress eventually led
> >to long-term health issues.
> >
> >Over the years I stayed in contact with first responders and field teams
> >from organizations such as WFP, UNICEF, the Red Cross, and various NGOs.
> >The feedback has remained consistent: when disasters strike, whether
> >earthquakes, floods, or large-scale displacement, teams still struggle to
> >bring up reliable communications quickly. What they need most is a mesh
> >network that works within minutes, not hours or days, and that continues
> >operating on battery power when infrastructure is down.
> >
> >I am fully aware that in active conflict zones Wi-Fi can be jammed or
> >restricted, for example due to drone countermeasures. However, there are
> >many other scenarios where Wi-Fi mesh remains extremely valuable:
> >evacuation centers, field hospitals, temporary shelters, flood-affected
> >villages, and coordination points for responders. In these environments,
> >fast, robust, and easy-to-deploy networking makes a very real difference
> >for coordination, family contact, and medical or logistical data sharing.
> >
> >Because of this, I am now restarting the project as MeshPoint V2. The focus
> >is updated hardware, improved battery life, and even simpler deployment,
> >while keeping the original goal: crisis response and off-grid or
> >underserved communities.
> >
> >In the original MeshPoint we used Babel. This was largely driven by
> >practical constraints at the time: our deployment tooling was based on
> >Nodewatcher, which was Babel-only. Technically, Babel served us very well.
> >It converged fast, was reliable, and worked nicely for small to
> >medium-sized networks.
> >
> >At the same time, I am well aware that many community networks and
> >real-world mesh deployments successfully used batman-adv, often through
> >Gluon or custom firmware builds. In larger, more dynamic, or highly mobile
> >topologies typical for crisis scenarios, the layer-2 approach and seamless
> >mobility properties of batman-adv are very attractive, especially when
> >nodes are frequently moved, powered on and off, or replaced in the field.
> >
> >For MeshPoint V2 I am evaluating batman-adv and would appreciate insights
> >on the following aspects, specifically in the context of crisis and
> >emergency deployments:
> >
> >Behaviour at larger scale in real deployments
> >In crisis scenarios networks often start small but can grow quickly as more
> >nodes are deployed by different teams or organizations. We are interested
> >in how batman-adv behaves when scaling to hundreds or more nodes in
> >non-ideal, real-world conditions, without centralized planning and with
> >limited ability for on-site tuning.
> >
> >Performance in sparse or highly mobile topologies
> >Nodes in the field are frequently moved, turned off, replaced, or
> >temporarily isolated. Vehicles, backpacks, and mobile command posts
> >constantly change network topology. We are looking for practical
> >experience with how well batman-adv handles frequent topology changes,
> >intermittent links, and sparse node placement without requiring constant
> >manual intervention.
> >
> >Suitability for battery-powered and intermittently connected nodes
> >Many nodes run on battery for long periods and may sleep, reboot, or
> >disappear entirely when power is lost. Low overhead, predictable
> >behaviour, and fast recovery after reconnect are essential. We are
> >particularly interested in any known trade-offs between routing
> >performance, control traffic, and power consumption in such environments.
> >
> >If there is existing work, documented limitations, field experience, or
> >design guidance relevant to these constraints, pointers would be greatly
> >appreciated. The goal is to build a system that field teams can deploy and
> >rely on under stress, without requiring deep networking expertise on site.
> >
> >Thank you for your time, and thank you to everyone who has contributed to
> >making mesh networking viable outside of labs and into real-world,
> >high-stakes situations.
> >
> >Best regards,
> >Valent Turkovic
> >https://www.meshpointone.com/
> >
> >Technical specifications of the original MeshPoint (for reference):
> >https://www.meshpointone.com/technical-specifications/