Subject: [manet] QoS issues in MANETs

From: Harpreet Arora <[email-masked]>
Date: Fri, 26 Apr 2002 14:50:27 -0400

Hi,

I am interested in finding the feasibility of a differentiated services model 
for MANETs. WHile thinking about the implementation of diffserv in MANETs, I 
came across the follwing problem : diffserv aims to push the complexity to the 
edge of the network, by dividing the network into edge and core nodes. How can 
we do this in a MANET? Specifically, how can we differentiate the network of 
nodes into edge and core nodes? Since the nodes are mobile, I feel that every 
node should have the capability of acting as an edge node, which would mark, 
meter and police the packets, and also as a core node, which would simply 
forward the packets on the basis of the DSCP. The nodes can assume either 
functionality depending on the situation. But what node assumes what 
functionality is the question. Any suggestions?

Harpreet
Research Assistant
ECE Department, Drexel University
Philadelphia, PA-19104

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From: "Manfredi, Albert E" <[email-masked]>
Date: Fri, 26 Apr 2002 14:56:42 -0400

Hi Arora,

Actually, diffserv pretty much acknowledges that every "core" node can just
as easily also be an "edge" node, and may therefore have to worry about such
complexities as access control from edge hosts. There is no attempt to
prevent core nodes from being edge nodes.

But diffserv does not get into any sort of signaling or access control
mechanisms between diffserv nodes and edge user hosts. People have mentioned
possible signaling mechanisms for use in diffserv nets, such as the RSVP
PATH and RESV messages. But always, such discussions were cut short on the
list, because they are not germaine to diffserv itself.

What diffserv offers is really a set of per-hop behaviors that every
diffserv node has to support as it routes diffserv-labeled packets. These
PHBs, when aggregated across a diffserv routing domain, create so-called
"per domain behaviors" for aggregated diffserv paths. That's it, pretty
much. And the MIB/PIB needed for diffserv node management, of course.

It seems difficult to be able to support diffserv routes with any sort of
stability if the hops of any "aggregated path" come and go frequently, but I
suppose this could make for an interesting research project!

Bert
[email-masked]

> -----Original Message-----
> From: Harpreet Arora [mailto:[email-masked]]
> Sent: Friday, April 26, 2002 2:50 PM
> To: manet
> Subject: [manet] QoS issues in MANETs
> Importance: High
> 
> 
> Hi,
> 
> A candle brightens the world around it. Unfortunately, it 
> creates a shadow of its own. It still serves the purpose it 
> is meant for. 
> **********************************************************************
> 
>

---

From: "Manfredi, Albert E" <[email-masked]>
Date: Fri, 26 Apr 2002 14:56:42 -0400

Hi Arora,

Bert

---

From: "Yasser A. Lotfy" <[email-masked]>
Date: Sat, 27 Apr 2002 13:15:12 -0700

Good answer,
Also, I'd to refer you to the INSEGNIA model, which provides a vihcle of handling traffic between two nodes. The other model which provided some enhancements to traditional DiffServ is the FQMM.

Always try to distinguish signalling from the model. FQMM represent a model, INSEGNIA is a model with it's own signaling approach. dRSVP is an ammendment to RSVP. 

Ingress, and egress could be anynode. Ingress are always nodes initiating traffic. Egress are those submitting traffic to different domain.

Yasser 
Carleton University

-----------------------------------------------------------------
Hi Arora,

Bert

> ECE Department, Drexel University

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---

From: "Yasser A. Lotfy" <[email-masked]>
Date: Sat, 27 Apr 2002 13:15:12 -0700

Good answer,

Yasser 
Carleton University

Bert

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From: Harpreet Arora <[email-masked]>
Date: Sat, 27 Apr 2002 19:08:37 -0400

Hi,

The Insignia approach does seem to be a good approach for QoS in MANETs, but 
it is based on per flow guarantees, not per class, and thus can have the same 
problems associated with Intserv model like scalability and implementation 
issues. Each flow reserves resources at every node it passes through. THe FQMM 
simply suggests that the highest class gets per flow provisioning, while the 
lower classes get per class provisioning, so in essence the model adds the 
complexity of the two models. And it does not suggest any means of 
implementing the model in MANETs. The basic issue still remains of which node 
will mark the packets so that the subsequent nodes can process them 
accrodingly. If the source node does that job, then there is a good chance 
that the node can misbehave and use a DSCP corresponding to a high priority 
PHB even when it does not need to. In that case, who does the policing to stop 
the flow?

thanks,
Harpreet

>===== Original Message From [email-masked] =====
>Good answer,
>Also, I'd to refer you to the INSEGNIA model, which provides a vihcle of 
handling traffic between two nodes. The other model which provided some 
enhancements to traditional DiffServ is the FQMM.
>
>Always try to distinguish signalling from the model. FQMM represent a model, 
INSEGNIA is a model with it's own signaling approach. dRSVP is an ammendment 
to RSVP.
>
>Ingress, and egress could be anynode. Ingress are always nodes initiating 
traffic. Egress are those submitting traffic to different domain.

---

From: "Yasser A. Lotfy" <[email-masked]>
Date: Sun, 28 Apr 2002 07:01:31 -0700

Hi,
If you're implementing a DiffServ Model on MANET, then allow me to add more questions need to be placed.
1- How can nodes agree on a set of DSCP?
2- How can nodes agree on a PHB?
3- Who will police traffic marking?

Yasser
Carleton University
---------------------------------------------------------------

Hi,

thanks,
Harpreet

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From: "Yasser A. Lotfy" <[email-masked]>
Date: Sun, 28 Apr 2002 07:01:31 -0700

Hi,

Yasser
Carleton University

Hi,

thanks,
Harpreet

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From: Harpreet Arora <[email-masked]>
Date: Sun, 28 Apr 2002 12:26:25 -0400

Yasser,

The set of DSCPs and the corresponding PHBs can always be set as standards. 
The third question remains unanswered.

Harpreet

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From: Harpreet Arora <[email-masked]>
Date: Sun, 28 Apr 2002 12:26:25 -0400

Yasser,

Harpreet