At 9/13/2010 10:57 PM, Jeromie wrote:
>Sorry, when ever people talk about mesh they most often mean 1 radio
>meshing.
First-generation "mesh networks" with one radio were awful. I didn't
think that was what Greg had in mind. Second-generation mesh
networks separated the backhaul ("meshing") from the user access, and
worked better. I actually like to use mesh in its original sense, to
refer to a network with an arbitrary topology allowing multiple links
per node. It contrasts with star and ring. A mesh is thus a
redundant network. The Internet is a mesh. SPF is a meshing
protocol, as is distance vector.
>Multiradio relays generally do not benefit from most of the
>mesh software.
Depends on the software, but you may be right with some of the
freeware mesh software designed for home routers running DD-WRT et al.
>OSPF or rSTP works very well and are generally stable
>and are generally supported and have many tools.
OSPF operates in IP. I'm trying to do everything at a lower layer
than that. RSTP works but is still fundamentally stupid; spanning
tree just avoids loops, but doesn't optimize. When the "mesh" gets
complex, you want real routing capabilities. I just have reasons to
avoid doing this in IP. But "bridging" is just a bad LAN hack too;
it doesn't scale to the radio world. I remember when we introduced
Ethernet bridges at DEC, somewhere around 1985. It sounded like a
good idea at the time. But a few years later, the head of network
archicture quipped, "Networks are a drug. Bridged networks are a
dangerous drug." Of course that was shortly before some
Microsoft-worshipping IT types started pushing big bridged multi-site
LAN Manager networks...
>I keep everything off
>the radio I possibly can and use them as bridges with a router behind
>them. With Mt having $40 units that is even easier and faster then
>ever.
I agree that this is a good idea. I am likely to do some radios as
cards plugged into the RB, like the SR71-15s which look really
good. But the access points and some links will be separate, on
Ethernet. Besides, the Ethernet RocketM sectors look better than
anything MT has. The specs are pretty close but the scuttlebutt on
the boards is that the UBNT cards outperform the R52HNs.
>On Mon, Sep 13, 2010 at 6:46 PM, Fred Goldstein <fgoldst...@ionary.com> wrote:
> > At 9/13/2010 09:23 PM, you wrote:
> >>With the low cost of Ubnt gear, why not run real relays? The area is
> >>small enough to not need a unreasonable amount of relays.
> >
> > What do you mean by real relays? A mesh or routed network or
> > whatever you want to call it is a set of relays. I may be missing
> > out on what you mean by the term, though; I use it generically.
> >
> >>On Mon, Sep 13, 2010 at 6:07 PM, Fred Goldstein
> <fgoldst...@ionary.com> wrote:
> >> > At 9/13/2010 07:02 PM, you wrote:
> >> >
> >> >>900 won't do 10 megs.
> >> >
> >> > The new Ubiquiti M-series Airmax 900 MHz radios should do it. MCS10
> >> > in a 5 MHz quarter-channel is around 10 Mbps. A lower-loss path
> >> > could allow MCS11 or MCS12. While you can't synchronize sectors,
> >> > they look like they will outperform Canopy at a fraction of the
> >> > price. Maybe they'll even ship this year. ;-)
> >> >
> >> > As to mesh, MT has HWMP+ as a layer 2 meshing protocol. It looks
> >> > promising, though there has apparently been very little use of it in
> >> > this hemisphere. But them I'm planning to do everything at layer 2,
> >> > trying to build a switched network if I can (vs.
> >> > bridged). BATMAN-Adv does a layer 2 mesh too, your basic open source
> >> > code. I don't know anyone using that one either. This type of
> >> > meshing is basically like routing, just operating below IP so it
> >> > treats IP (or other protocols, hint hint) as payload and doesn't try
> >> > to deal with IP addresses.
> >> >
--
Fred Goldstein k1io fgoldstein "at" ionary.com
ionary Consulting http://www.ionary.com/
+1 617 795 2701
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