Subject: [manet] research for ad hoc community networks?

From: David Young <[email-masked]>
Date: Tue, 23 Jul 2002 13:50:47 -0500

In my community, a small band of community organizers and computer geeks
is trying to build a community network using inexpensive 802.11 radios. I
feel certain that our success will depend on our adoption of ad hoc
networking principles: We do not anticipate the magnitude of private
or governmental investment that will help us afford to individually
configure stations on the network, to buy space on radio towers for
wireless base stations, to point antennas from rooftop to base station,
or to administrate hundreds or thousands of stations. But with stations
that auto-configure their IP numbers, that tolerate ever-changing link
topologies, that discover and choose Internet gateways, we will be able to
build a network by modest expenditures (such as the cost of a computer,
radio, and omni antenna) and we will keep network administration costs
under control.

As I read the commercial literature and the scientific literature
on ad hoc networks, I am struck by two things:

 * it is difficult (for me) to infer from a routing protocol's performance
   in a "random waypoint" test how it will perform on rooftops in compact,
   semi-wooded neighborhoods of two-story homes

 * insofar as "rooftop networks" have been deployed, it is only by
   commercial ventures (MeshNetworks.com, Nokia RoofTop, others) who
   use technologies that are trade secrets, so I can draw no conclusions
   from their experience

I have the ear of some researchers in ad hoc networks on this mailing
list, so I ask you, are they any of your findings that speak directly to
the problem of networking communities from rooftops?

Will anyone advocate for a particular combination of protocols to build
a rooftop network?

Dave

-- 
David Young             OJC Technologies
[email-masked]     Engineering from the Right Brain
                        Urbana, IL * (217) 278-3933

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From: "Phil Neumiller" <[email-masked]>
Date: Tue, 23 Jul 2002 15:24:02 -0400

Hi Dave,

A questions for you.

1).  Do you expect this network to provide access to mobiles (i.e. wireless devices
       in cars) or pedestrian mobiles?  

The reason I ask is, 802.11b does not work well at all for mobile devices.

Other comments below...

----- Original Message ----- 
From: "David Young" <[email-masked]>
To: <[email-masked]>
Sent: Tuesday, July 23, 2002 2:50 PM
Subject: [manet] research for ad hoc community networks?

>    semi-wooded neighborhoods of two-story homes

If you used 802.11b outdoors, not very well.  You can use an effective radiated
power of (ERP) of 4 watt out of an omni antenna.  If you do the path loss equations
at 2.5 GHz you see your range will be somewhat limited.  Also it will be 
greatly affected by multi-path and foliage loss so higher data rates will become
unuseable pretty rapidly. 

With 802.11b we have measured about 1 dB of loss / meter through trees and 
vegetation here in Florida (this is a HEAVY foliage environment).  In your lightly
wooded scenario, 802.11b may do a bit better.  There is not a whole lot of 
"free" 2.4 GHz channel sounder information available for various propagation 
morphologies, something that could greatly enhance your success.

>    use technologies that are trade secrets, so I can draw no conclusions

We (MeshNetworks) support many different radios.  Our patented radio technology
and  proprietary stuff (patent pending) are radios that work better in outdoor
multi-path fading environments at higher data rates (have RAKE and doppler
compensation for high speed mobiles).  

> the problem of networking communities from rooftops?

Range will be a problem.  Security will be a problem.  Also, the telcos are trying
to squeeze money out of "free" spectrum by disallowing DSL/Cable backhaul.
I can't wait till that hits the courts see http://www.tmcnet.com/tmcnet/columns/laura071902.htm

> Will anyone advocate for a particular combination of protocols to build

I believe Rooftop uses RIP, but their system is not truly ad hoc (or mobile) and
is intended for stationary subscribers.  I also believe it using 802.11 (original not
8 but the 2 Mbps FHSS radios).  There may be a possibility to use our products,
but some of the "carrier class" stuff would be of no use to you.  I would recommend
you start out on a small scale and do some measurements of your own.  I think you will
be disatisfied with the acheivable range of 802.11b on omnis pretty quickly.  This means
you will have to deploy more infrastructure then you might have wanted to.  As for
protocols, I recommend AODV or DSR.  I am sure that there are lots of people on 
the list (also read the archives) that would be happy to recommend one over the
other to you! :-)

Cheers!

Phil Neumiller

---

From: "Phil Neumiller" <[email-masked]>
Date: Tue, 23 Jul 2002 15:24:02 -0400

Hi Dave,

A questions for you.

Other comments below...

----- Original Message ----- 
From: "David Young" <[email-masked]>
To: <[email-masked]>
Sent: Tuesday, July 23, 2002 2:50 PM
Subject: [manet] research for ad hoc community networks?

Cheers!

Phil Neumiller

---

From: zb <[email-masked]>
Date: Wed, 24 Jul 2002 14:22:21 +0900

Hi,

I have a question on how does the ad hoc network begin to work? When device
A and device B are in a MANET, they do not know IP address and service
ability of each other. There can be multihop between device A and device B.
How does the device A know it can get required service from device B and
communicate with device B?

Thanx.

bin
*************************************
Zhen Bin

i-Networking lab,
Samsung Advanced Institute of Technology,
San14-1, NongSeo-ri, Kiheung-Eup,
Yongin, Kyungki-do, 440600, Korea

82-31-2809569 (fax)
82-31-2809534 (o)
82-31-2122268 (h)
*************************************

---

From: zb <[email-masked]>
Date: Wed, 24 Jul 2002 14:22:21 +0900

Hi,

Thanx.

bin

i-Networking lab,

82-31-2809569 (fax)
82-31-2809534 (o)
82-31-2122268 (h)

---

From: Frank Dinies <[email-masked]>
Date: Wed, 24 Jul 2002 12:01:41 +0200

Hi Zhen,

for proactive algorithmens like ADV or FSR there is no problem. Mainly because 
this algorithmens rely on periodically sent advertisments. So after a short 
boot-up-time, when a new device wants to participate, it knows about his 
enviroment and vice versa. But this is only true for proactive algorithmens.

For reactive algorithmens or on-demand-algorithmens  this is not true. This 
algorithmens rely on special information or mechanismens for the boot-uptime 
to scan their enviroment.

But keep in mind. Proactive algorithmens are best in enviroments with rapid 
change and much participants. On-demand-ones roughly for the contrary. For 
sensors that transmit from time to time small amounts of data for example is 
an on-demand-one perfect.

hope this helps

frank

looking in the RFCs or drafts could give you an idea. the bootup problem 
mostly is not trivial !

---

From: Frank Dinies <[email-masked]>
Date: Wed, 24 Jul 2002 12:01:41 +0200

Hi Zhen,

hope this helps

frank

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From: "Philippe Jacquet" <[email-masked]>
Date: Wed, 24 Jul 2002 16:51:43 +0200

Dave,

I think there are many communities using IEEE 802.11b. For example look at
wireless seattle ([email-masked]). It seems that the technology
works well enough for them. You may need high gain antennas sometimes (far
roofs).
A priori I don't see any problem with ad hoc architecture, but to my
knowledge it will be the first time it will be used in a community. I don't
see any specific problem in the choice of the routing protocol (you will
fight more with
the deployment than with the routing protocol). AODV has probably the more
choice in available codes. I have a secret preference for proactive
protocols (e.g. OLSR) because they are easier to deploy and are more
compatible with existing internet technology (IP stack, etc).

Regards,
Philippe

---

From: "Philippe Jacquet" <[email-masked]>
Date: Wed, 24 Jul 2002 16:51:43 +0200

Dave,

Regards,
Philippe

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From: Saurabh Jain <[email-masked]>
Date: Wed, 24 Jul 2002 12:18:35 -0400 (EDT)

Dave

I suggest you view the Master's thesis of Benjamin A. Chambers. It's title
is "The Grid Roofnet: a Rooftop Ad Hoc Wireless Network". He has worked on
community ad hoc networks, using the Grid routing system. The thesis is
available for download from the Grid website at
http://www.pdos.lcs.mit.edu/grid/

Regards,
Saurabh

> Will anyone advocate for a particular combination of protocols to build

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From: Saurabh Jain <[email-masked]>
Date: Wed, 24 Jul 2002 12:18:35 -0400 (EDT)

Dave

Regards,
Saurabh

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From: zb <[email-masked]>
Date: Thu, 25 Jul 2002 08:43:07 +0900

Hi, Frank,

  Thanks your reply.

  I think, to make an ad hoc network to do something, two thing must be
done:
1) to get an IP address of itself
2) to find the node which can provide the required service and get its IP
address
Then, the data can be exchanged between the two nodes. In MANET, there are
drafts on routing and IP address autoconfiguration. But, how to do service
discovery in ad hoc network? It seems there is no working group on service
discovery. Does it belong to upper layer which is out of  IETF? Besides, how
does the service discovery collaborate with the routing in ad hoc network?

regard,

bin
----- Original Message -----
From: "Frank Dinies" <[email-masked]>
To: "zb" <[email-masked]>
Cc: <[email-masked]>
Sent: Wednesday, July 24, 2002 7:01 PM
Subject: Re: [manet] how does ad hoc network do something?

Hi Zhen,

for proactive algorithmens like ADV or FSR there is no problem. Mainly
because
this algorithmens rely on periodically sent advertisments. So after a short
boot-up-time, when a new device wants to participate, it knows about his
enviroment and vice versa. But this is only true for proactive algorithmens.

hope this helps

frank

---

From: zb <[email-masked]>
Date: Thu, 25 Jul 2002 08:43:07 +0900

Hi, Frank,

  Thanks your reply.

regard,

bin
----- Original Message -----
From: "Frank Dinies" <[email-masked]>
To: "zb" <[email-masked]>
Cc: <[email-masked]>
Sent: Wednesday, July 24, 2002 7:01 PM
Subject: Re: [manet] how does ad hoc network do something?

Hi Zhen,

hope this helps

frank

---

From: David Young <[email-masked]>
Date: Tue, 30 Jul 2002 17:27:59 -0500

Thank you, this was enormously useful.

Has anyone else built a test-bed like Mr. Chambers'?

Dave

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From: David Young <[email-masked]>
Date: Tue, 30 Jul 2002 17:27:59 -0500

Dave