Subject: [manet] QoS over shared media

From: "Yasser A. Lotfy" <[email-masked]>
Date: Tue, 09 Jul 2002 23:35:29 -0400

Good day,

In responce to Nilsson's e-mail, I can't help but think of QoS based on transimission over shared media. To make my point clear ckeck this simple example. Assume A, B, C, D, E, & F are nodes geographically positioned as drawn (just for simplicity). If A needs to transfer a high bandwidth stream to E via C, while B needs a low bandwidth transfer to F via D. It is possible to increase the share of link AC of the bandwidth (since link AC & BD share the same media).

A ====> C ====> E
B ----> D ----> F

The problem is that QoS solutions have always been implemented on IP layer. Implementing this kind of solution will require tight marriage with MAC layer. In addition, the dynamics of varying MAC resources based on the need seem to carry lots of difficulties.

My question is whether you can point me to any research done on that area? INSIGNIA, and FQMM (not quite sure about SWAN) they all work on IP layer without investigating this kind of otimization. Does Bluetooth, or 802.11b provide any mean to carry over such ideas?

Inputs are highly appreciated.

Yasser
Carleton University

_____________________________________________________
Supercharge your e-mail with a 25MB Inbox, POP3 Access, No Ads
and NoTaglines --> LYCOS MAIL PLUS.
http://www.mail.lycos.com/brandPage.shtml?pageId=plus 

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

---

From: Rex Buddenberg <[email-masked]>
Date: Wed, 10 Jul 2002 08:51:17 -0700

At 11:35 PM -0400 7/9/02, Yasser A. Lotfy wrote:
>Good day,
>
>In responce to Nilsson's e-mail, I can't help but think of QoS based 
>on transimission over shared media. To make my point clear ckeck 
>this simple example. Assume A, B, C, D, E, & F are nodes 
>geographically positioned as drawn (just for simplicity). If A needs 
>to transfer a high bandwidth stream to E via C, while B needs a low 
>bandwidth transfer to F via D. It is possible to increase the share 
>of link AC of the bandwidth (since link AC & BD share the same 
>media).
>
>A ====> C ====> E
>B ----> D ----> F

Yasser, let's make one of your assumptions explicit: high bandwidth 
(as you used the term) = high priority.  In which case your logic is 
ok.

But a lot of the high precedence traffic is fairly small chunks of 
data.  Consider a chem/bio warning system that we implement over the 
Internet (with or without MANET segments in it).  The sensors in the 
system are scattered around sniffing for Bad Stuff.  When they sniff 
such, they push out a datagram (probably to multiple addresses) 
announcing that fact -- should only take a few dozen bytes to say 
everything possibly useful.  That traffic needs to be able to push 
aside some streaming VTCs that are using the same plumbing.  In other 
words, 'low bandwidth' now equates to high priority.

>
>The problem is that QoS solutions have always been implemented on IP 
>layer. Implementing this kind of solution will require tight 
>marriage with MAC layer. In addition, the dynamics of varying MAC 
>resources based on the need seem to carry lots of difficulties.

You are on target here -- both the multicast and QoS (e.g. diff-serv 
DSCP) characteristics need to be reflected through from network to 
datalink layer.  A quickie would be to mirror the DSCP data through 
from IP datagrams to MAC layer frames.  In a lot of cases, the 
primitives are there, but the linkages are not -- for instance, FDDI 
supports 8 layers of priority but there are no general purpose ways 
(i.e. vendor-neutral standardization) to get the TOS bits copied from 
datagram to frame.

>
>My question is whether you can point me to any research done on that 
>area? INSIGNIA, and FQMM (not quite sure about SWAN) they all work 
>on IP layer without investigating this kind of otimization. Does 
>Bluetooth, or 802.11b provide any mean to carry over such ideas?

So far, all work that I know of is media-specific.  Phil Neumiller's 
underbelly discussion on this list is aimed at generalizing some of 
this ... Phil et al, correct and adjust my take.

-- 
b

---

From: Rex Buddenberg <[email-masked]>
Date: Wed, 10 Jul 2002 08:51:17 -0700

-- 
b

---

From: Anders Lindgren <[email-masked]>
Date: Sat, 13 Jul 2002 20:17:59 +0200

Hello,

I have done some work, evaluating different QoS schemes for IEEE 802.11.
My publications can be found at
http://www.sm.luth.se/~dugdale/index/publications.shtml

This does not consider the interactions with IP, but might at least give
you an idea of the solutions available for 802.11.

/Anders

---

From: Anders Lindgren <[email-masked]>
Date: Sat, 13 Jul 2002 20:17:59 +0200

Hello,

/Anders