Re: [Gzz] 25th, 26th, 27th & 28th (hh)

[hemppah]

Quoting Tuomas Lukka <address@hidden>:

> > > > -For research questions a, b, and c, I know what the p2p field has to
> > > offer: the
> > > > best effort is DHTs with O(log n) (with small variations).
> > > 
> > > Again: with what assumptions? Who has to be trusted? How reliably is a
> > > block
> > > going to be found?
> > 
> > For normal conditions, with n nodes, the DHT algorithm require O(log n)
> hops to
> > reach arbitrary destinations *and* each node must mantain information
> about
> > O(log n) neighbours. Additionally, DHT is very robust for failures; for
> example,
> > when 20% of the nodes simultaneously fail, less than 0.1% of the routes
> fail.
> 
> Routes, but what about blocks and finding them?

(Umm..as routes still exist, finding blocks should possible with O(log n) ?)

The point was that DHTs are robust in the face of failuers, attacks and
unexpectedly high loads.


> 
> > The biggest problem in DHTs is that there might be hostile nodes which
> route
> > requests purposely to wrong directions. However, there are proposal how
> these
> > kinds of issues could be solved.
> 
> Well, these you must describe.

Yes, but I won't describe them here :).

> 
> > > Does this work also with the "local store" model?
> > 
> > What do you mean by "local store" (replication or something else) ?
> 
> I mean: for each node, how much capacity should it allocate to the P2P
> network?
> I.e. if everyone has 50MB of P2P data that they *WANT* to store and
> allocate
> 2MB for data that the algorithm wants to store, what happens? Does only the
> 2MB
> get really used by others?

As far as I know, there is no limitation like this in DHTs (or in other
algorithms (?)).

> 
> > >> -For e, there are some proposals, e.g. SQL-like searchs in DHTs and
> keyword
> > >> searchs. However, this is quite Gzz specific, e.g. Urn-5 etc. (?)
> > 
> > >Urn-5: think about it as a very unique keyword. 
> > 
> > What do you mean by saying (in research questions): "Mist? tied?n, mik?
> on
> > *suht* oikea ?" --> the word "suht".
> 
> How do I know, if starting just from the *words* "Helsinging sanomat",
> which
> urn-5 and which key are the right ones? To distinguish between real and 
> fake newspapers.

Reputation mixed with a digital sigature ? Or a simply decision by social
connection (as in alpine paradigm) ? Hash/integrity of *something* ? What is
*something*, I have to look more of it.

btw, is it possible to be CAs (Certificate Authorities) in Gzz p2p (like
"Sanomatalo" which we can trust on in the case of "Helsingin sanomat") ?


> 
> > > > -For f, same algoritmical limits hold true in this too. 
> > > 
> > > Which ones?
> > 
> > Now, look answer above.
> 
> Transclusions referring is not quite the same as the above: there are more
> transclusions per document than urn-5's per document.
> This is essentially a distributed database.

Uum...but still in p2p environment e.g. based on DHTs ? Has transclusion a block
id ? How we can refer to specific transclusion (is it possible) ?

These are rookie-like questions as I don't know Gzz/Xanalogical structure wery 
well.

> 
> > > > This is also Gzz
> > > > specific and is, at least someway, implentation issue when we have
> the
> > > basic
> > > > infrastructure builded (a, b, c)
> > > 
> > > It is similar to c) but not the same.
> > 
> > That's true, but (of course) same algorithmical limits applies also in this
> case.
> 
> You haven't really made clear the algorithmical limits, their *exact*
> requirements
> etc.
> 
> This is what you should probably work on most intensively: make really
> exact
> definitions of what the different algorithms can mathematically do, based
> on
> what assumptions.

Ok. That's not difficult task to do, because e.g. Gnutella uses a breadt-First
traversal in directed graph (with depth limit l), Freenet depth-first traversal
(with depth limit l) and DHTs performance comes "out-of-box from the data
structure" with certain assumptions (how to implement hash name to a key in and
m-bit virtual address space).


> 
> > > > -For g and h, same as f (?)
> > > 
> > > Not a satisfactory answer.
> > 
> > Hmm...in practise, what g and h mean ?
> 
> Explain; what don't you understand?

I undestand the basic idea of transclusion ("part of text which refers to
external text, but this is invisible to the reader of text"). 

What are the basic differences between transclusions and Xanadu links ?


-Hermanni






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