[CUWiN-Dev] Fwd: Re: Mesh Networking Project

[Quantum Scientific]

Some more thoughts on the hardware below, in a discussion with PC Engines, the maker of the WRAP boards.

May I also submit for consideration, the Senao CB3 bridge:
http://www.senao.com/english/product/product_wireless01_outdoor_1.asp?tp1id=02&tp2id=02&proid=000107
http://www.guerrilla.net/reference/80211_mod/Senao_AP3_CB3/index.html

It's a rock-solid router that's been used extensively in the LocustWorld project, and has roaming and Radius client!  Maybe the reference design could be purchased, or older ones could be had in the right price range.

There are slight hardware differences between the AP and CB, the most important being POE in the CB.  Either can be flashed to serve the others' role.  It has plenty of Tx power and so-so Rx sensitivity, although if I'm not mistaken it has the Prism chipset.  I can get more hardware detail if ppl are interested.

Most of the other options I've inquired about, including PC104, are too expensive.

Best,

Carl Cook



----------  Forwarded Message  ----------

Subject: Re: Mesh Networking Project
Date: Wednesday 26 January 2005 12:06
From: Quantum Scientific <Info at quantum-sci.com>
To: Pascal Dornier <pdornier at pcengines.ch>

On Monday 24 January 2005 16:13, Pascal Dornier wrote:
> Au1550 is about $25 for the slowest (3xx MHz) speed grade. I don't know how 
> much lower this can be driven, but I haven't seen much discounting on the 
> SC1100 CPU yet.
> 
> 128 MB DDR DRAM is about $16 on the spot market.
> 
> 64 MB NAND flash is about $4.75. Add about $3 to $4 if you need a IDE to flash
> controller, otherwise spend time on software (flash file system). A 64 MB 
> CF card is about $9 FOB China.
> 
> To these costs you have to add PCB fab, power supply circuit (passive POE like
> on my current WRAP boards if you want low cost), Ethernet PHYs + magnetics
> etc. Excluding the radios, I can hit the $100 target. There is only so much 
> I can do on the board cost, but I can do some things in the board design to 
> reduce the total solution cost, e.g. by designing the board to mate well with an 
> outdoor case without added adapter cables. I like the passive POE because I 
> can feed it with a $3.50 AC adapter and a $2.50 POE injector, and it avoids 
> some of the costs of a 802.3af compliant solution (48V isolating DC-DC, 
> classification circuit etc).

I see.

Is there an alternative processor >300MHz with hardware crypto functions?  

I've read of some initial problems with your WRAP boards.  Can you clarify?

 
> What does the second LAN port get used for ? One port LAN, one port WAN ?

Ideally there should be provision for a second ethernet interface and a second WiFi radio.  The second ethernet interface is for joining other routers together to feed three or four sector antennas.  The second WiFi is so the unit can act as an inexpensive bridge for point-to-point.

 
> If you look at something like the www.mini-box.com WRAP-Box, there is a lot 
> of cost in the Ethernet cabling alone - if a conventional RJ45 can be plugged 
> through a weatherproof grommet, a lot of money can be saved.

Yes, agree.  (Man, your English is flawless)

 
> I will not touch radio designs - use miniPCI cards instead. The sockets are 
> cheap, and buy a lot of flexibility and freedom. If a supplier's chipset or cards 
> don't work well, you can fire him and use something else. The prices you 
> see on sites like www.netgate.com etc. include a high margin, in Taiwan you 
> can get a/b/g cards sub $30 (for a b/g, probably below $20, if you're not too 
> picky about the chipset). 

Agree with mPCI too, but the sense of the project seems to be heading toward modifying memory of an existing router or buying a reference design and adding memory, etc.  I'm giving alternate options though.

I would like to examine the CM9 WiFi card, which has the Atheros AR5004 chipset, for the possibility of increasing Tx power.  Can you refer me to a few of these Taiwanese vendors?

 
> What is your usage scenario ? Indoor / outdoor ? What kind of temperature 
> range ?  Power source ? What kind of antennas will get connected ? What 
> kind of RF connectors ? How will the LAN ports be used ? 

Almost all nodes will be outdoor in a mast-mounted enclosure, with POE or solar.  Outdoor temp will range from -20F to 110F, but in colder climates the electronics should keep the inside warm enough.  In hotter climates, maybe an aluminum enclosure with IR reflecting paint.  Trying to avoid fans, for reliability reasons.

I have been lobbying for horizontal polarization, but it's nearly impossible to overcome the problem of cost.  I'm also lobbying for 700 or 900MHz for better range, penetration, and quiet, but the cost of the radio may preclude this.

The design isn't solidified enough to determine RF connectors.  The key developers are completely tied up trying to get Milestone II out the door.

Best,

Carl Cook
 


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