RE: [manet] DYMO and other routing protocols

["Krishna Sankar \(ksankar\)" <ksankar at cisco.com>]

Philippe,

	Interesting discussions. Couple of questions:

> space. Personally I have preference to proactive approach 
> because it is richer and gives better internet legacy. 
<KS>
	I would argue exactly the opposite - reactive protocols are more "internet-native". Let me explain:

	a)	In internet you resolve end point locations thru DNS (and optimize it by caching and querying when a cache is invalid, one does not query every time nor one has all the resolution database locally)
	b)	Naturally internet is packet based not circuit based
	c)	The routes do change based on congestion, peering, even optimized edge routing and multi topology routing based on declarative policies and "coloring"
	<I am just naming a few instance I know of from my very limited knowledge>
</KS> 
> Some adaptability feature in DYMO would be welcome, not 
> necessarily proactive, but at least some memory based feature 
> could help.
<KS>
	Are you talking about spatial interpolation based on history ? Mobility algorithmics based on 1st and 2nd order derivatives of mobility vectors - For example if we know a node is moving, if we can infer the acceleration and also the spatial topology, we could possibly say where it could be and what the route could be knowing the nodes in that vicinity ...
</KS>

Cheers
<k/>
> -----Original Message-----
> From: Philippe Jacquet [mailto:philippe.jacquet at inria.fr] 
> Sent: Friday, June 08, 2007 4:12 AM
> To: David Murray
> Cc: manet at ietf.org
> Subject: Re: [manet] DYMO and other routing protocols
> 
> I would say that from a very broad perspective, on-demand 
> protocols discriminate routes with respect to time and 
> proactive protocols discriminate routes with respect to 
> space. Personnally I have preference to proactive approach 
> because it is richer and gives better internet legacy. 
> Objectively the two approaches have their advantages and 
> drawbacks and the two should be considered.
> 
> This said, I don't think that on-demand and proactive 
> approaches are represented at the same level in MANET. OLSRv2 
> has "space" adaptability: 
> i.e algorithms which automatically adapt to space and 
> topology variety, including for instance the MPR mechanism. 
> In DYMO I don't see an equivalent "time" adaptibility that 
> goes beyond the default values in timers. I think this may 
> explain why the protocol performs great in some scenario and 
> very poorly in other.
> 
> Some adaptability feature in DYMO would be welcome, not 
> necessarily proactive, but at least some memory based feature 
> could help.
> 
> Philippe
> 
> David Murray a écrit :
> > Hi,
> > 
> > I am wondering how DYMO fits in with the other routing protocols. I 
> > have read a number of papers that discuss how on-demand routing 
> > protocols like DSR/AODV work better in highly mobile environments 
> > where movement is fast, CPU and memory are low and batteries are 
> > limited. Equally, in situations where movement is very low, 
> and there 
> > are no power limitations, protocols like OLSR/TBRPF/STAR 
> perform better.
> > 
> > So, I have a mental picture of OLSR/TBRPF being 
> predominantly used in 
> > stationary 802.11 mesh devices and AODV/DYMO being used to connect 
> > users mobile devices ush as phones and PDAs. Is this correct or are 
> > things not quite as simple as this? (I know RFC 2501 
> discusses MANET 
> > applications and characteristics but the discussion is 
> quite general)
> > 
> > If this is correct, it seems to me that DYMO and AODV are 
> used in very 
> > similar situations (the ad hoc interconnect between users 
> devices). I 
> > am aware that DYMO is a simplified version of AODV both in code and 
> > network operation. It seems like the major difference is the path 
> > accumulation feature in DYMO which allows nodes to append their 
> > information to a RREP to give other nodes better knowledge of the 
> > topology. It also seems that the hello feature has been removed in 
> > DYMO. So, is DYMO likely to be a replacement for AODV or do 
> they have different uses/applications?
> > 
> > Thanks for your time
> > 
> > Dave
> > 
> > 
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> > 
> > 
> 
> 
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