[hackerspaces] Mesh network specs

Todd todd at cruxtech.net
Wed Dec 28 11:49:48 CET 2011

Thanks to everyone who has responded.

For the mesh, I do envision as being peer to peer, the only reason to 
use backhauls is because I am anticipating that we may not be able have 
good enough coverage that the speed won't suck, so it should still be 
peer to peer and the backhauls, of which should be few and just to make 
large distance jumps,  would be transparent bridges.

I have not worked with mesh networking before, not have I had enough 
routers to test anything out yet, although that will change in the next 
2 weeks, I want it to be as transparent as possible to the end users, 
and we will be setting up each router (with openWRT) personally, the 
people who host the nodes shouldn't ever touch them. So it should work 
like a normal hotspot with captive portal, at least that is what I am 
hoping for.
The assumption here is that the mesh would be handing out IPs via DHCP, 
or would that not work ?

For the backhaul links I am going with professional (read expensive) 

Airaya WirelessGrid-300 5 Ghz 300 Mbps with 24 dbi Panel Antennas
So it would be 802.11N for the backhauls, and 802.11G for the end users.
This is also why the routers in the mesh network should have dual radios.

The power shouldn't be an issue, or even having the routers exposed to the elements, my plan is to have the
routers indoor in the homes of the people who are hosting it, so the routers should be safe from the elements,
and the antennas would be external to the building, so any routers chosen would need to have replaceable antennas
(in this case DIR-655) although I am wondering what the max length between the antenna and the router can be for the SMA connectors ?

On 12/26/2011 12:08 PM, The Doctor wrote:
> Hash: SHA1
> ObDisclaimer: I'm one of the developers of Project Byzantium.
>> I am looking to build a mesh network in chicago, The way we are
>> planning to do it is, we have an uplink set up in a datacenter
>> downtown with a 100mbit connection, and a place for the antenna on
>> the building that will go across the street to the 1st hop, which
>> will then have several point to point links to the greater mesh
>> network. So the plan is
> That sounds like a good first draft of your backhaul.  Good.
>> primarily to have many meshes, probably about 20, each with ~8
>> wireless
> When you say 'mesh', do you mean a true peer-to-peer wireless mesh, or
> are you using 'mesh' to describe your architecture of backhauls and
> access point for clients?  What mesh routing protocol are you
> considering using?  Which have you tried deploying?  What is the
> hardware and software of your expected client base?
>> routers, which are connected via point to point bridges. None of
>> this is commercial, so we will not be worrying about things like
>> zoning fr the antennas since they will all be on private
>> properties. My question is,
> I've heard it said that perhaps you should contact the FFC to see what
> they think of this because they may take a negative interest in your
> repurposing bits of the consumer unlicensed spectrum for a project of
> this size.
>> does this sound like a good plan, and if so, what specific
>> hardware should be looking to use ?
> That's going to be a difficult question to answer because much of our
> work has to do with repurposing and modifying off-the-shelf equipment.
> What I can say is that wok-fi (https://en.wikipedia.org/wiki/WokFi)
> works pretty well for long-haul links between nodes.  You should
> probably consider mounting your antennae under overhangs of some kind
> to give them some protection from the elements.  If you can hide a
> whole node's hardware under an overhang to protect it from rain and
> snow, so much the better.
> What are your power requirements looking like?  How do you plan on
> powering individual nodes?
>> Please be specific as in technically specific (5ghz 16.5dbi yagi
>> antenna) or list the manufacturer/link to hardware that is being
>> suggested.
> I don't want to assume, but my guess would be that you're going to use
> 802.11g links for your backhaul?  Are you going to encrypt the
> backhauls or not?
> - -- 
> The Doctor [412/724/301/703]
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