[Babel-users] Restarting MeshPoint – seeking advice on routing for crisis/disaster scenarios

[Valent@MeshPoint]

Hello Juliusz,

Good to hear from you again, and thanks for the detailed reply.

I agree on cellular changing the landscape a lot. In practice, in 
deployments I have seen and worked with, cellular is often overloaded, 
intentionally restricted, or simply unavailable exactly when ad hoc 
connectivity is needed most. That is why I still look at mesh as a 
complementary tool rather than a replacement for cellular.

On jamming and mixed link types, I am fully aligned with your point. 
>From a practical networking perspective, this is where layer 3 really 
shines. If links are abstracted properly, the routing protocol should 
not care whether the next hop is WiFi, Ethernet, or something more 
exotic. In the field, mixed setups often survive precisely because not 
everything fails at the same time.

Regarding seamless mobility, thanks for pointing me to sroamd. I 
actually was not aware of it before your email. Conceptually, layer 3 
mobility makes a lot of sense to me, especially from an operational 
standpoint. In community and emergency networks I have worked with, 
large layer 2 domains tend to look good in small tests, but become 
fragile once you have real users, real traffic, and imperfect links.

On the large scale behaviour question, I mean this in a very pragmatic 
way. Many community and emergency style networks are sparse, asymmetric, 
and power constrained. Nodes come and go, links flap, and you often end 
up with long chains rather than dense meshes. The challenge is keeping 
control plane traffic bounded and predictable so that routing does not 
end up consuming most of the airtime or CPU as you scale into the 
hundreds or thousands of nodes.

To keep this grounded in reality, I have been testing in a lab setup 
that tries to resemble real community networks as closely as possible. I 
am using meshnet lab to spin up large topologies based on real Freifunk 
network graphs, rather than synthetic grids or random meshes. This 
allows comparing behaviour on the same realistic topologies and then 
sanity checking the results on actual hardware in smaller setups. Have 
you, or anyone else on the list, worked with meshnet lab before? I would 
be interested to hear how well it matched real world behaviour in your 
experience.

I also wanted to ask one more general question about Babel itself, more 
about process than implementation details. When you first started 
developing Babel, was it driven mainly by theoretical reasoning at the 
beginning, with real world testing coming later, or were simulators, lab 
setups, or live networks involved from early on? Or was it always a mix 
of both. I am asking from an operator perspective, since in my 
experience many issues only show up once you put protocols into messy, 
real topologies.

Best regards,
Valent


------ Original Message ------
>From "Juliusz Chroboczek" <jch at irif.fr>
To "Valent Turkovic" <valent at meshpointone.com>
Cc babel-users at alioth-lists.debian.net
Date 18.12.2025. 1:04:43
Subject Re: [Babel-users] Restarting MeshPoint – seeking advice on 
routing for crisis/disaster scenarios

>Hello, Valent, good to hear from you again.
>
>>  Between 2015 and 2018 I ran the MeshPoint project – a simple, rugged
>>  Wi-Fi hotspot designed to work in the toughest conditions.
>
>I remember :-)
>
>>  Unfortunately, financial issues forced me to pause the project after 2018
>
>In addition to the issues you mention, the big change since the early
>2000s is the wide availability of cheap cellular connectivity.  Hence, the
>demand for mesh networks has changed quite a bit.
>
>>  I know that in active conflict zones Wi-Fi can be jammed
>
>The nice thing about having a layer 3 routing protocol is that you can
>combine technologies: Babel is designed to handle a network that has both
>wired and wireless links, and that uses multiple wireless technologies at
>the same time (WiFi at various frequencies, UWB, infrared laser, etc.).
>In such a network, Babel should be able to find a path consisting of
>whichever links are not jammed at a given time.
>
>Of course, this assumes that the opponent is not able to jam all links
>simultaneously.
>
>>  - BATMAN-adv-style seamless mobility
>
>I started working on sroamd[1], which implements seamless mobility at
>layer 3, but then Covid happened, and I got interested in
>videoconferencing.  I guess we could revive it if there's interest.
>
>[1]: https://github.com/jech/sroamd
>
>>  - Better large-scale behaviour for hundreds-to-thousands of nodes in
>>    sparse or battery-constrained setups
>
>Could you please clarify?
>
>-- Juliusz