Subject: [manet] How to increase packet delivery ratio in MANETs

From: "Marwaha Shivanajay" <[email-masked]>
Date: Fri, 25 Oct 2002 11:55:58 +0800

Dear All,
How would we select routes in MANETs if we want to ensure/meet high
packet delivery ratio (PDR) requirements. Are there any papers which
deal with this. Also are there any papers/mechanisms developed for
achieving higher packet delivery ratio for certain class of traffic
which have specific packet loss requirements. Can we compromise delay to
ensure high PDR in MANETs??

(In my view, we need to know the stability of the links in a route to
ensure high packet delivery ratio. For this we may use eiter "HELLO
Messages" or "GPS information". Using HELLO messages has the
disadvantage of more power & bandwidth consumption and NS-2 results have
shown that HELLO messages (when used with AODV) decrease the PDR in the
first place by 5-10% compared to AODV with link layer notification. On
the other hand, GPS assisted routing has constraints working indoors.)

So how to ensure/meet packet loss requirement (atleast for some classes
of traffic) ?

Regards,
Shivanajay Marwaha
***********************
Research Scholar
ECE Dept, NUS,
10 Kent Ridge Crescent,
Singapore 119260
***********************

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From: "Marwaha Shivanajay" <[email-masked]>
Date: Sat, 26 Oct 2002 12:15:34 +0800

The reason seems to be correct, that the packets will be dropped untill
the link failure is detected via periodic HELLO beacons. Additionally,
HELLO messages consume extra bandwidth & battery power.

An advantage of using periodic HELLO beacons is that nodes know their
neighbors & the respective link stabilities (from signal strength of the
received beacons) which can be used for selecting stable links in a
route (this should decrease pkt drop).

I'm not too sure how fast and robust is LL notification, someone may
kindly explain or give some pointers.

A small doubt in my mind about LL responding quickly as against periodic
HELLO beacons:

In case there is no mobility but very high traffic exists, will the LL
permanently report LL-errors because it couldn't obtain the medium due
to high traffic and this may unneseccarily trigger route discovery by
AODV although no node is moving????

Regards,
Shivanajay Marwaha 
******************************
Research Scholar
Elec. & Comp Eng. Dept.,
National Univ. of S'pore (NUS)
10 Kent Ridge Crescent,
Singapore 119260
******************************

The pessimist complains about the wind; the optimist expects it to
change; the realist adjusts the sails.

-----Original Message-----
From: Philippe Jacquet [mailto:[email-masked]] 
Sent: Friday, October 25, 2002 7:47 PM
To: Marwaha Shivanajay; [email-masked]
Subject: Re: [manet] How to increase packet delivery ratio in MANETs

Is not the PDR discrepancy between AODV with link layer notification and
AODV with HELLO due to the fact that with the latter one has to wait for
a periodic hello to detect link failure and meanwhile packets are lost?

Philippe
----- Original Message -----
From: Marwaha Shivanajay <[email-masked]>
To: <[email-masked]>
Sent: Friday, October 25, 2002 5:55 AM
Subject: [manet] How to increase packet delivery ratio in MANETs

> which have specific packet loss requirements. Can we compromise delay 
> to ensure high PDR in MANETs??
>
> disadvantage of more power & bandwidth consumption and NS-2 results 
> have shown that HELLO messages (when used with AODV) decrease the PDR 
> in the first place by 5-10% compared to AODV with link layer 
> notification. On the other hand, GPS assisted routing has constraints 
> working indoors.)
>
> So how to ensure/meet packet loss requirement (atleast for some 
> classes of traffic) ?
>
> Regards,
> Shivanajay Marwaha
> ***********************
> Research Scholar
> ECE Dept, NUS,
> 10 Kent Ridge Crescent,
> Singapore 119260
> ***********************
>

---

From: "Marwaha Shivanajay" <[email-masked]>
Date: Sat, 26 Oct 2002 12:15:34 +0800

Regards,
Shivanajay Marwaha 

-----Original Message-----
From: Philippe Jacquet [mailto:[email-masked]] 
Sent: Friday, October 25, 2002 7:47 PM
To: Marwaha Shivanajay; [email-masked]
Subject: Re: [manet] How to increase packet delivery ratio in MANETs

Philippe