Dave Close wrote:
> Jack Unger wrote:
> >I predict that Mesh Networks will find (after several deployments)
> >that the actual throughputs through 3 mesh nodes will be significantly less
> >than the throughput over a well designed single hop (pt-multipoint)
> >network.
>
> Your calculations are fine but don't agree with the test cases Mesh says
> they have run. As I wrote earlier, I am not here to endorse or promote
> Mesh, but I did want to correct some apparent misunderstandings. They
> should be invited to make a presentation to the group.
I agree that they should be invited to make a presentation.
I hope that the schedule is such that I can be present (as the totally
vendor-neutral entity that I am) to hear and to challenge their claims
if they appear to be "stretching" the truth beyond belief.
>
>
> They do use two types of radio, a proprietary one called QDMA and 802.11b.
> They say they could extend the technology to 802.11[ag] easily, given a
> customer. Obviously, only the 802.11b products are compatible with off-
> the-shelf consumer products.
> I can't find any literature on their tests. However, I recall them saying
> they had set-up about 27 nodes linearly with about half-mile spacing
> along a straight rural Florida road, and were able to get decent through-
> put along the entire chain. Don't trust my memory for the exact numbers.
For the reasons that I outlined, I find this hard to believe.
>
>
> Two issues with your calculations. One, if the point-to-point connection
> has a weak signal (because of the distance), its speed will be much below
> each link of the relay approach. Two, 802.11b actually uses three channels,
> not one, so some degree of collision avoidance is possible. 802.11[ag] use
> more channels.
Again, if you use a multiple-channel node, it's a completely different story (as
I outlined
before).
jack
>
> --
> Dave Close, Compata, Costa Mesa CA "You ain't goin' nowhere, son."
> [EMAIL PROTECTED], +1 714 434 7359 -- Grand Ole Opry manager to
> [EMAIL PROTECTED] Elvis Presley, 1954
--
Jack Unger, President-Wireless InfoNet ([EMAIL PROTECTED]) 818 227-4220
Vendor-Neutral WISP Training - http://www.ask-wi.com/2002workshops.html
Author - "Deploying License-Free Wireless WANs"
http://www.amazon.com/exec/obidos/ASIN/1587050692/
