Subject: MAC LAYER DESIGN

From: [email-masked]
Date: Thu, 19 Nov 1998 21:03:21 +0530 (IST)

I am working on mac layer design for adhhoc networks.
 I want to know which is the best suitable mac protocol
 and what are the criteria on which you evaluate mac layer
                                          thanku
                                          sastradhar

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From: Zygmunt Haas <[email-masked]>
Date: Thu, 19 Nov 1998 14:26:38 -0500 (EST)

Hi Sastradhar,

You may want to take a look at our following paper:

J. Deng and Z. J. Haas, ``Dual Busy Tone Multiple Access (DBTMA): 
A New Medium Access Control for Packet Radio Networks,'' IEEE ICUPC'98, 
Florence, Italy, October 5-9, 1998

Best of Luck!

Zygmunt.
=-=-=-==

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Prof. Zygmunt J. Haas             tel: +1-607-255-3454
Wireless Networks Laboratory
323 Frank Rhodes Hall             fax: +1-607-255-9072
School of Electrical Engineering  
Cornell University                e-mail: [email-masked]
Ithaca, N.Y. 14853                
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From: "Fred L. Templin" <[email-masked]>
Date: Thu, 19 Nov 1998 12:24:17 -0800

Forgive me if you were already aware of this, but the IEEE 802.11
Distributed Coordination Function (DCF) provides one such model.
I can't comment as to whether/not this is the "best suitable mac
protocol", however. Perhaps others can provide more feedback....

Fred
[email-masked]

P.S. The IEEE homepage at: www.ieee.org has references to 802.11

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From: Chai Keong Toh <[email-masked]>
Date: Thu, 19 Nov 1998 19:54:24 -0500 (EST)

Just to add that Prof. JJ Garcia Luna from UCSC and Prof. Mario Gerla from
UCLA have some work  related to Ad Hoc MAC. You may want to check out
their web sites. Also, BBN networking group may have  something in that
area too, I think.

Prof. C-K. Toh, Assistant Professor,
Mobile Multimedia & HiSpeed Network Lab, 
School of Electrical and Computer Engineering
Georgia Institute of Technology, Atlanta,
Georgia GA 30332, USA. Fax: 404 894 7883 
---------------------------------------------

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From: Youngbae - Ko <[email-masked]>
Date: Thu, 19 Nov 1998 23:13:25 -0600 (CST)

Dear Dr. Toh

Could you direct me what kinds of works have been done by BBN 
in the area of ad hoc MAC ? If there are any papers or reports, 
please let me know.  Thanks in advance.

- Youngbae Ko
  ===================
  Research Assisstant
  Mobile Computing Lab
  Texas A&M University

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From: SJ Lee <[email-masked]>
Date: Thu, 19 Nov 1998 21:52:16 -0800 (PST)

Thanks for mentioning our Lab's work, CK.
Indeed, we have MACA-PR and MACA-BI.
The papers can be downloaded from http://www.cs.ucla.edu/NRL/wireless/

Thanks.

SJ

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From: Ram Ramanathan <[email-masked]>
Date: Fri, 20 Nov 1998 12:57:14 -0500

Most of BBNs ad hoc networking as a group has been in the network layer. 
I personally have done some fairly theoretical work on channel assignment
modelled as constrained graph coloring. Perhaps this is what C-K meant.
My most recent paper on this was in Infocom 97 titled "A Unified Framework
and Algorithm for Channel Assignment in Wireless Networks" and can be 
found under the "related publications" link in 
http://www.net-tech.bbn.com/dawn/dawn-index.html.
(This URL also describes BBN's network layer activities under the GloMo
program for those interested.).

This paper, however, is not relevant to the original query that started
this thread. None of the responses have really answered that question
to my best knowledge. The question was

>I am working on mac layer design for adhhoc networks.

Have fun.

>I want to know which is the best suitable mac protocol

It is like asking: which is the best movie ever made :) everybody has their
favorite MAC protocol (especially the people who invent one :) and a lot 
depends on the  requirements.

>and what are the criteria on which you evaluate mac layer

Again, depends on requirements and constraints. Do you want to support
bursty traffic or not? Do you have a large percentage of unidirctional
links? Do you want to do multicasting? Do you want to give access delay
guarantees? Capacity guarantees? On-demand access? 

Once you define the problem for which you want the MAC protocol for, then
you can talk about criteria. These could range from obvious ones like
fairness and freedom from deadlock, to more sophisticated ones like 
minimal energy or interference mitigation.

I haven't seen work address this. None of the cited work look at "requirments"
or "criteria" for MAC like Scott Corson and co have done for MANET routing.
I think Fred Templin's idea of starting from the IEEE 802.11 is a good one.

While we are talking about existing ad hoc MAC  work, I have seen some good
work by defense contractors like ITT Aerospace, Rockwell Collins etc.
Unfortunately, these guys rarely publish except in Milcom. 

MAC is supposed to be out of scope for this working group, so let me stop
before I get called for wasting bandwidth.

Cheers,

-Ram.

> Date: Thu, 19 Nov 1998 23:13:25 -0600 (CST)
> From: Youngbae - Ko <[email-masked]>
> X-Sender: youngbae@mozart
> To: Chai Keong Toh <[email-masked]>
> cc: Zygmunt Haas <[email-masked]>, [email-masked], 
>     [email-masked]
> Subject: Re: MAC LAYER DESIGN
> In-Reply-To: <[email-masked]>
> Message-ID: <Pine.GSO.3.96.981119225324.20308A-100000@mozart>
> MIME-Version: 1.0
> Content-Type: TEXT/PLAIN; charset=US-ASCII
> Sender: [email-masked]
> Precedence: bulk
> 
> Dear Dr. Toh
>

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From: "M. Scott Corson" <[email-masked]>
Date: Fri, 20 Nov 1998 13:39:37 -0500 (EST)

> before I get called for wasting bandwidth.

Ram,

I don't think you're wasting BW... ;-)

I think the protocol designers in this group have to be very cognizant
of the link/physical layers over which they intend to run their protocols.
One of the major issues (little addressed so far here as a group) is the 
interface to the link layer from network layer.  Each link layer is
somewhat different, and an adaptation layer between the network and 
link layer is required for each link layer (such as 802.11) to implement
standard services for the network layer....initially, this service
set may be fairly small (e.g. 1-hop unicast, multicast, or broadcast 
with or without reliability) over contention-based link layers like 802.11.
But, as technology evolves, and more capable link layers are developed
that support, for example, forms of reservation-based access, this 
service set may grow richer over time.  An adaptation layer supporting
this service set, which sits between the device driver and the network layer, 
can be developed for each new link layer. Alternatively, if the driver
writers themselves seek to conform to some standard (something akin to
the GloMo Radio API), then the network layer folks can simply write to
this standard.  A portion of this WG's charter is to consider 
the interface to the link layer, so this is a relevant discussion.

-Scott

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From: Chai Keong Toh <[email-masked]>
Date: Fri, 20 Nov 1998 23:42:10 -0500 (EST)

Ram,

I was thinking of referring Youngbae Ko to you prior to your reply.
(SJ: Thanks for your pointers to the related papers)

The web site pointer is helpful. I agree with you that DARPA contractors
working on MAC and/or routing ssues normally do not publish in 'academic' 
conferences or journals, possibly with the exception of MILCOM and 
SUPERCOMM. My past involvement with a major DARPA project confirms
this point.

About the issue of MAC, I think it is important for routing protocol
designers to understand the underlying channel access method and physical
transport. I think it is impossible to support QoS by merely looking at
a specific protocol layer only. This reminds me of the liaison established
between the Wireless ATM Working Group at the ATM Forum and the ETSI BRAN
group, which is concentrating more on the radio and MAC issues.

Based on what Scott had said in his last e-mail, I think it is good if
IETF MANET group could establish a link with IEEE 802.11 or ETSI HIPERLAN
group. The European HIPERLAN group works on MAC issues for High Performance
LAN which includes both centralized access control and fully distributed
access control. 

Maybe this issue can be discussed formally or informally at the upcoming 
IETF meeting in Florida?

Regards,

C-K. Toh, Assistant Professor,
Mobile Multimedia & HiSpeed Network Lab, 
School of Electrical and Computer Engineering
Georgia Institute of Technology, Atlanta,
Georgia GA 30332, USA.