[olug] Cox sucks

Sam Tetherow tetherow at shwisp.net
Wed Jul 18 05:56:15 UTC 2007


Benjamin Watson wrote:
> Sam,
>
> I really appreciate your reply, as it has got me thinking.  To date, I
> haven't done my due diligence crunching the financial aspects of such
> an implementation, but your comments did get me Google'ing and I'm
> beginning to see where some of your figures come from.  Some of the
> things I've yet to fathom are the number of mesh nodes it would take,
> and how many users each node could serve adequately.  However, like
> cell-site deployment, I suppose a population density study would need
> to be performed to determine the optimal placement for nodes, etc.
>
> I guess my vision, initially, is to cater to the casual outdoor user
> with a laptop/pda/etc sitting in a park, walking down the street, or
> sitting outside on a balcony or backyard patio and that this user
> desires to do some light web browsing, check e-mail, etc.  I'm not
> looking to serve people pipes to facilitate first person shooter
> gaming, VOIP, or video streaming.  By no means am I ambitious enough
> to use 802.11x as a last-mile technology to serve home users.  If I
> were to entertain the idea of a wireless ISP (WISP), I'd look into
> WiMAX (802.16).  Of course, that technology isn't cheap and demands
> CPE.
>   
More importantly, it demands licensed spectrum currently and if 802.16h 
does finally get WiMAX into license free space I don't think you will 
have much gain over other proprietary implementaions (motorola, trango, 
alvarion) or even 802.11n which some are hopeful will provide commodity 
2.4G pricing with significant speed improvements.

I do run a WISP in 802.11a/b space successfully, but I realize what my 
limitations are as well.
> -----
> "Topology issues would be next on the list as you mentioned mesh which
> usually implies connecting multiple APs wirelessly for backhaul so you
> further reduce your available bandwidth. Optimal would be a fully routed
> network which would mean that data only flows through nodes that it has
> to flow through, but this would negate roaming the mesh. If you allow
> roaming then you can effectively halve the available bandwidth for each
> node wirelessly linked together."
> ----
>
> Yes and no.  The equipment I'm working with now are dual radio mesh
> routers.  The radios are Ubiquiti XTreme Range "carrier class" radios.
>  Radio 1 is an 11b radio acting as an Access Point, whilst radio 2 is
> an 11a radio acting as a backhaul to other mesh routers.  Of course,
> each router also has a wired ethernet port to route traffic over that
> link in the event it is connected to a wired LAN to the Internet.  All
> together, each mesh router costs around $700.  But if Nicholas
> Negroponte can make laptops with mesh-capable wireless interfaces for
> $100 (and I recall a company in India is aiming at making a laptop for
> $50), I see no reason (even it it boils down to buying in bulk) that
> this price couldn't come down substantially.
>   
You could manufacture an equivalent for about half that price in bulk.
> Each mesh router runs Linux and other open source (free) software to
> reduce cost.  One interesting bit of software is OLSR (Optimized Link
> State Routing) which runs on each router's 11a interface.  This allows
> each mesh node to discover one another, setting up optimal routes to
> the Internet.  Nodes without a direct (wired) connection use the 11a
> radio to route traffic, while those with a direct connection use the
> Ethernet interface.  The thing I like about this technique is that the
> network topology is rather flexible, self-healing, and scalable.  If
> you have an AP that is being over-loaded by users, or need to expand
> coverage, stand up another mesh router in the vicinity of existing
> ones.  Of course, a bit of graph theory is needed to ensure that node
> failures don't isolate parts of the network.
>   
As this model scales the noise floor in 802.11a will increase, 
especially if you are using an omni antenna for the backhaul which will 
give you the self-healing aspect.
> I'll agree that, in this 2 radio scheme, you will see a 1/N bandwidth
> fall off for each wireless hop that is traversed to get to the
> Internet.  This is due to the inherent simplex nature of wireless
> radio communication.  However, I'd propose a 3 radio solution which
> would eliminate this phenomenon and provide full-duplex node-to-node
> wireless links.  The author/owner of www.meshdynamics.com has some
> good test data backing up my claim.
>
> During my initial 2 radio testing, I've found that 3 wireless hops
> provides "adequate" light web browsing, etc.  But 4 or more hops
> degrades the bandwidth to a crawl and you start to experience TCP
> timeouts, etc.
>
> To sum it all up, I whole-heartedly agree that this is a huge
> challenge, but that is what makes it fun to try to solve it.  I guess
> I'm angling this concept from a technical (is it possible) perspective
> and not the business (is it financially feasible) perspective.  There
> are a host of issues (provisioning and deployment, security, quality
> of service, etc.) that my project won't endeavor upon, but I still
> feel that free outdoor wireless access to the Internet is a novel
> concept worth exploring.
>
>
> Ben
>
>   




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