Subject: [manet] RE: [manet] IP addresses in MANET

From: "����" <[email-masked]>
Date: Mon, 1 Jul 2002 15:52:18 +0800 (CST)

Hello Scott:
    As David Young says, Using power control to increase MANET performance is an active research area in MANET. It sure will increase MANET’s throughput. However, firstly, because of practical reason, transmitting power can not be decreasing without limit; secondly, when the transmitting power is low enough, it means that the talking area or clustering area is very small, In such network, the mobility of nodes will become a big problem:) 
   Practically speaking, if MANET can serve more than 10000 nodes freely, I think it is enough for real implementation. I see no case which needs more nodes than that:)

Hai Wang

> Hello Hai Wang,
> 
> I have been thinking about the characteristics that I want in a radio ... and working with a local company to develop one that might be well oriented towards MANETs.  When you say:
> 
> > No matter what structure, what algorithm you use, when the number of nodes increases, 
> > the routing OH or clustering OH will increase steadily(except we use autonomous region 
> > concept in MANET :) ). At last, the OH will eat up the bandwidth. Just before that, when 
> > there is some point where the link quality is bad, the OH will choke the traffic too, make the 
> > performance unacceptable. So, I think that the size limit of a MANET may depend on 
> > smallest link bandwidth in a network. For hierarchical scheme, the bandwidth of links 
> > among cluster heads will be of great concern.
> 
> I have thought about one way to possibly deal with this, although I will not claim to have thought this through with a lot of detail.
> 
> What if I were able to use software to alter the output power and sensitivity of my radio?  When I found myself in a situation where I have too many "peers" or the cluster size is getting very large (I am not sure that this is accurate language as I am still coming up to speed!) then I would issue software commands to the radio to decrease my output power, and sensitivity so that I would decrease the radius that I can effectively communicate.
> 
> In a sense, what if I could decrease and increase my effective "cell" size through software?  Would that assist in this problem?
> 
> 
> Scott C. Lemon
> HumanXtensions L.L.C.
> http://www.HumanXtensions.com
> http://the.Inevitable.Org/anism
> 
>    "People often talk about it being the journey, not the destination.
>         Consider the possibility that there is no destination ...
>                     that in life there is only journey!"
>

---

From: "����" <[email-masked]>
Date: Mon, 1 Jul 2002 15:52:18 +0800 (CST)

Hello Scott:

Hai Wang

---

From: "Mullen, John P. (Contractor)" <[email-masked]>
Date: Mon, 1 Jul 2002 07:07:42 -0600

Hi Scott,

I think reducing transmitter power is a good tactic to control cluster size.
It is also a good idea from the perspective of conserving limited power.
However, I'm not sure reducing receiver sensitivity is a good idea.  By
reducing output power, you will reduce the area over which the transmitter
will interfere with other transmissions.  However, reducing sensitivity will
only add to the problem of data collisions.  In addition, reduced
sensitivity will require higher transmit power and will offer less
protection against Raleigh fading, multipath, etc.

It would be better to focus on the output power reduction and allow the
receiver to make the most of the received signal.  This will reduce the
probability of two adjacent clusters interfering with one another while
maintaining good chances of a successful packet transfer.  It will also lead
to a simpler control problem, since only one element will be modified
instead of two.

John Mullen

Hello Hai Wang,
 
I have been thinking about the characteristics that I want in a radio ...
and working with a local company to develop one that might be well oriented
 
> among cluster heads will be of great concern.
 
I have thought about one way to possibly deal with this, although I will not
claim to have thought this through with a lot of detail.
 
What if I were able to use software to alter the output power and
sensitivity of my radio?  When I found myself in a situation where I have
too many "peers" or the cluster size is getting very large (I am not sure
that this is accurate language as I am still coming up to speed!) then I
would issue software commands to the radio to decrease my output power, and
sensitivity so that I would decrease the radius that I can effectively
communicate.
 
In a sense, what if I could decrease and increase my effective "cell" size
through software?  Would that assist in this problem?

Scott C. Lemon
HumanXtensions L.L.C.

John P. Mullen, 
Contractor

Mail to:
    Director
    USATRAC-WSMR
    Attn: ATRC-WBC (John Mullen)
    White Sands Missile Range, NM  88002-5502

Phone:  
    (505) 678-5275
    DSN 258-5275

_______________________________________________
manet mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/manet

---

From: "Mullen, John P. (Contractor)" <[email-masked]>
Date: Mon, 1 Jul 2002 07:07:42 -0600

Hi Scott,

John Mullen

Hello Hai Wang,

 

Scott C. Lemon
HumanXtensions L.L.C.

John P. Mullen, 
Contractor

Mail to:
    Director
    USATRAC-WSMR

Phone:  
    (505) 678-5275
    DSN 258-5275

---

From: "Mullen, John P. (Contractor)" <[email-masked]>
Date: Mon, 1 Jul 2002 07:35:14 -0600

Hi Hai Wang,
 
Certainly, minimal routing update control, together with bandwidth, would be
a limiting factor, but it is not possible to say in general where that is.
The volume of update traffic is related to the rate of change within the
net.  The effectiveness of a protocol may also be related to traffic
patterns.  For example, in AODV, the need to update depends only on the rate
of change among links involved with active routes.  If those links consist
of only 10% of the total possible links, then a ten fold increase in
topology change would, in theory, be possible, compared to a MANET in which
100% of the links are involved in active paths or a protocol that attempts
to keep all kink information updated, regardless of whether or not it is
involved in an active route.
 
10,000 sounds like a very large number, but it is just the maximum size of a
telephone exchange in the US.  At New Mexico State University, we have a
need for two such exchanges.  If there is a need for such a MANET, somebody
will come up with something to provide at least some management of the
situation.  Also, bandwidth is relative.  Thirty or forty years ago, the
bandwidth in wired nets was about the same as bandwidth in MANETs.  People
found ways to cope with that then and they will now.
 
I remember, in 1978, a technician patiently explaining to me why the data
rate on a conditioned telephone line could never exceed 3kb.  According to
the theory in use at the time, it was an insurmountable barrier.  Well, some
bright guy figured a way around the theory and now I've got a cheap 56 kb
modem at home.  There is no telling what the future has in store for us.
 
Although we can safely assume that whatever technology is out there, the BW
in MANETs will be significantly less than in wired nets, it is hard for me
to say with any confidence that a particular limit on that BW, and hence
MANET size, exists.
 
John Mullen

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Saturday, June 29, 2002 2:49 AM
To: [email-masked]
Cc: [email-masked]
Subject: [manet] Re: RE: [manet] IP addresses in MANET

Hi John:
Thanks for your detailed explaining. I agree with you in most part, except:
[John M] …Given a "nice" situation, there would be no practical limit to
the MANET,....

I think there is a limit to the MANET. Wireless is different from wired, its
bandwidth is limited, and it can hardly to make a breakthrough. No matter
what structure, what algorithm you use, when the number of nodes increases,
the routing OH or clustering OH will increase steadily(except we use
autonomous region concept in MANET :) ). At last, the OH will eat up the
bandwidth. Just before that, when there is some point where the link quality
is bad, the OH will choke the traffic too, make the performance
unacceptable. So, I think that the size limit of a MANET may depend on
smallest link bandwidth in a network. For hierarchical scheme, the bandwidth
of links among cluster heads will be of great concern. Perkins has shown
that there is a 10000 nodes network under test, however,! he did not show us
the bandwidth he use. 10000 is a rather astonishing number to me :) 

BR.
Hai Wang

---

From: "Mullen, John P. (Contractor)" <[email-masked]>
Date: Mon, 1 Jul 2002 07:35:14 -0600

Hi Hai Wang,

 

John Mullen

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Saturday, June 29, 2002 2:49 AM
To: [email-masked]
Cc: [email-masked]
Subject: [manet] Re: RE: [manet] IP addresses in MANET

Hi John:

BR.
Hai Wang

---

From: "Manfredi, Albert E" <[email-masked]>
Date: Mon, 1 Jul 2002 10:17:43 -0400

Some miscellaneous rambling:
 
Decreasing power is useful to decrease the size of cells, to make more efficient use of RF spectrum. In a system with base stations or access points, the advantages seem obvious. The wired infrastructure will have to be upgraded for a greater traffic load, but the individual wireless cells will support the same number of hosts in a smaller area, resulting in greater density of mobile hosts.
 
In an ad-hoc network, the advantage doesn't seem so obvious (to me). Since ad-hoc networks depend on mobile hosts for all their intra-MANET routing, decreasing power means increasing the number of hops required, which means that there will be more choke points in the network and more hosts involved in the average data path. I suppose that if one introduces faster mobile hosts while reducing the power, same as one had to upgrade the wired infrastructure in the cell-based network with base stations, then maybe I can understand how you'd expect better performance.
 
Bert

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Monday, July 01, 2002 3:52 AM
To: [email-masked]
Cc: [email-masked]; [email-masked]
Subject: [manet] RE: [manet] IP addresses in MANET

Hello Scott:
As David Young says, Using power control to increase MANET performance is an active research area in MANET. It sure will increase MANET?ˉs throughput. However, firstly, because of practical reason, transmitting power can not be decreasing without limit; secondly, when the transmitting power is low enough, it means that the talking area or clustering area is very small, In such network, the mobility of nodes will become a big problem:) 
Practically speaking, if MANET can serve more than 10000 nodes freely, I think it is enough for real implementation. I see no case which needs more nodes than that:)

Hai Wang

---

From: "Manfredi, Albert E" <[email-masked]>
Date: Mon, 1 Jul 2002 10:17:43 -0400

Bert

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Monday, July 01, 2002 3:52 AM
To: [email-masked]
Cc: [email-masked]; [email-masked]
Subject: [manet] RE: [manet] IP addresses in MANET

Hello Scott:

Hai Wang

---

From: "Mullen, John P. (Contractor)" <[email-masked]>
Date: Mon, 1 Jul 2002 09:20:41 -0600

Hi Bert,
 
It all turns on the density of your hosts and the patterns of
communications.  If you have a very large number of hosts in a rather small
geographical area, you will have increased contention for the RF channel.
By reducing power, you reduce the potential for interference among hosts
attempting unrelated communications on the same channel, but in
significantly different geographical locations.  If, on the other hand,
those conversations are of interest to all nodes, then reducing power will
increase the number of hops and channel utilization.  
 
For example, suppose your MANET consists of clusters of hosts that are about
1 km apart.  However, within a cluster, each node is within a few meters of
at least one other node.  When communications is within a cluster, it would
be prudent, to limit transmit power to that level necessary to carry out
communications within that cluster, but not high enough to cause
interference between clusters.  On the other hand, if you need to
communicate from one cluster to another, a higher power level would be
needed.
 
Also, if we agree that the MANET hosts are likely to be portable
battery-powered units, then managing transmitter power is also important
from the perspective of conserving network resources.  
 
I would say that the ability to change transmitter power has potential for
more efficient MANET management, but its success will turn on the ability of
the protocol to detect situations in which the different power levels are
appropriate.
 
John Mullen

-----Original Message-----
From: Manfredi, Albert E [mailto:[email-masked]]
Sent: Monday, July 01, 2002 8:18 AM
To: '??'
Cc: [email-masked]
Subject: RE: [manet] RE: [manet] IP addresses in MANET

Decreasing power is useful to decrease the size of cells, to make more
efficient use of RF spectrum. In a system with base stations or access
points, the advantages seem obvious. The wired infrastructure will have to
be upgraded for a greater traffic load, but the individual wireless cells
will support the same number of hosts in a smaller area, resulting in
greater density of mobile hosts.
 
In an ad-hoc network, the advantage doesn't seem so obvious (to me). Since
ad-hoc networks depend on mobile hosts for all their intra-MANET routing,
decreasing power means increasing the number of hops required, which means
that there will be more choke points in the network and more hosts involved
in the average data path. I suppose that if one introduces faster mobile
hosts while reducing the power, same as one had to upgrade the wired
infrastructure in the cell-based network with base stations, then maybe I
can understand how you'd expect better performance.
 
Bert

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Monday, July 01, 2002 3:52 AM
To: [email-masked]
Cc: [email-masked]; [email-masked]
Subject: [manet] RE: [manet] IP addresses in MANET

Hello Scott:
As David Young says, Using power control to increase MANET performance is an
active research area in MANET. It sure will increase MANET?ˉs throughput.
However, firstly, because of practical reason, transmitting power can not be
decreasing without limit; secondly, when the transmitting power is low
enough, it means that the talking area or clustering area is very small, In
such network, the mobility of nodes will become a big problem:) 
Practically speaking, if MANET can serve more than 10000 nodes freely, I
think it is enough for real implementation. I see no case which needs more
nodes than that:)

Hai Wang