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" <[email protected]>
To "Valent Turkovic" <[email protected]>
Cc [email protected]
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
