[hackerspaces] Mesh network specs

Todd todd at cruxtech.net
Wed Dec 28 13:24:29 CET 2011


Oh I forgot to mention, yes preferentially all traffic on this network 
would be encrypted, I am not sure how to implement that though (outside 
of just using WPA2 on everything)

On 12/28/2011 4:49 AM, Todd wrote:
> 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) 
> hardware,
>
> 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:
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>> 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]
>>
>> PGP: 0x807B17C1 / 7960 1CDC 85C9 0B63 8D9F  DD89 3BD8 FF2B 807B 17C1
>> WWW: https://drwho.virtadpt.net/
>>
>> "Apathy is suicide and we will bear the blame!" --Psykosonik
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