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What Happens Inside a 100-Hop IPv6 Wireless Mesh Network?

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Re: What Happens Inside a 100-Hop IPv6 Wireless Mesh Network?

#5
post #3

I feel the article ended before it started. Did they find anything? What are some interesting rules of thumb? Is there any theory you can draw about long path networks?

Agreement. The article gives a good introduction and methodology - but doesn't say what the experiment showed. Is there any conclusion? Should I stop my network at 50 nodes? What were the propagation delays? Might a star-based topology make more sense?

Re: What Happens Inside a 100-Hop IPv6 Wireless Mesh Network?

#7
Heh, I walked a similar path ~7 years ago. Wanted to get started developing a mesh network routing algorithm that could handle a hundred hops, got distracted and built a mesh networking test harness / simulation system instead (https://github.com/pirate/mesh-networking).

Never got around to finishing a full routing algorithm, though we did have a lot of fun testing wacky network topologies and protocols that solved subsets of the problem.

The closest we came was designing a 2 or 3 tiered system, where nodes self-arrange into clusters of up to 256 nodes with one elected leader to coordinate. The routing table is replicated on all nodes (eventually consistent), but the leader handles all changes. Then there's Layer 2 routing between clusters with a similar leader election system to handle inter-cluster routing.

We tried to figure out a way to make the routing stateless, (e.g. by encoding a node's position in the graph in its id, sort of like a phone number has a country code, then area code, etc.), but stopped working on it before figuring out a good approach for broadcasting ID changes without flooding the network with broadcast traffic beyond small network sizes.

Nowadays there are established mesh routing algorithms that solve all these problems (like B.A.T.M.A.N., Contiki, 802.11s, or even BGP), but it's still a really exciting field that I dream of working in professionally someday.

https://www.open-mesh.org/projects/open-mesh/wiki

Re: What Happens Inside a 100-Hop IPv6 Wireless Mesh Network?

#8
What are some of the biggest public/private wireless mesh networks out there? (I suppose 'biggest' by measure of node count -- or maybe area covered?). For those networks, how deep are they in practice? 100 hops seems unrealstic, but a great way to find scaling problems.

Re: What Happens Inside a 100-Hop IPv6 Wireless Mesh Network?

#9
post #8

What are some of the biggest public/private wireless mesh networks out there? (I suppose 'biggest' by measure of node count -- or maybe area covered?). For those networks, how deep are they in practice? 100 hops seems unrealstic, but a great way to find scaling problems.

I work on mesh networks for the smart utilities (think smart metering in India).

Our deployments are in the hundreds of thousands and individual meshes of up to 1000 nodes. We use similar technologies to described in the article (802.15.4, RPL, IPv6, CoAP, 6LoWPAN, DTLS, etc).

Topology-wise, our meshes don't tend to exceed 10 hops (chains like described here aren't great, tho can function).

Re: What Happens Inside a 100-Hop IPv6 Wireless Mesh Network?

#10

Heh, I walked a similar path ~7 years ago. Wanted to get started developing a mesh network routing algorithm that could handle a hundred hops, got distracted and built a mesh networking test harness / simulation system instead ( https://github.com/pirate/mesh-networking ). Never got around to finishing a full routing algorithm, though we did have a lot of fun testing wacky network topologies and protocols that solved…

I currently like https://yggdrasil-network.github.io

AFAIK, each node generates its own key, and keys are then deterministically organized in a tree topology. Then, as you said, there's a lot of established systems. Yggdrasil is from the cjdns lineage.

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