[p2p-hackers] DHT or unstructured?

[Michael J. Freedman]

At the latest NSDI, Castro et al had a paper "Debunking some myths about 
structured and unstructured overlays" that argued that 'anything 
unstructured systems can do, structured systems can do better'.

   http://www.research.microsoft.com/~antr/MS/myths.pdf

Basically, it wasn't providing specific algorithms, e.g., for prefix 
search as Sean suggested, but instead suggesting that you can leverage the 
structure for other than DHT queries.  For example, (1) if you want a very 
rich query language -- which is the main reason people suggest using 
unstructured systems -- you can always improve performance by using the 
structured overlay to _direct_ the query, as opposed to random walks. 
(2) Explicitly provide better organization for super-peer hierarchies 
(heteroPastry), as opposed to ad-hoc techniques.

I forget all the details, but it may be of some interest to system 
builders.  Of course, there is more complexity in maintaining a structured 
system (in terms of implementation), although unstructured systems assume 
similar amounts of maintenance traffic to ensure good connectivity and 
liveness of peers.

--mike


On Tue, 5 Jul 2005, Hailong Cai wrote:

> Date: Tue, 5 Jul 2005 14:34:19 -0500
> From: Hailong Cai <hcai at cse.unl.edu>
> Reply-To: Peer-to-peer development. <p2p-hackers at zgp.org>
> To: 'Peer-to-peer development.' <p2p-hackers at zgp.org>
> Subject: [p2p-hackers] DHT or unstructured?
> 
> Hello, everybody
>
> As we know, DHTs receive a lot of attention from academy while unstructured
> systems thrive on the market.  I just want to know how these two types of
> P2P would evolve in the near future, say, in the following 5 years.  Which
> one will prevail and which one will die, or maybe they may merge into some
> kind of hybrid system?  Could you please share your thoughts on this?
> I don't know if this question has been asked before, but I want to know your
> ideas at present.
>
> A.  DHT will succeed and unstructured systems will die
> B.  Unstructured systems will continue growing and DHTs will fade away.
> C.  They will merge into one.
> D.  They will coexist but with different applications.  For example,
> unstructured systems for file sharing, and DHTs for distributed storage
> system.
> E.  Other
>
>
> Thanks
> Hailong

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www.michaelfreedman.org                              www.coralcdn.org