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Mapping Peer-to-Peer
Networks
Peer-to-peer (P2P) file-sharing networks
are perhaps the most innovative new information space to emerge
on the Internet in recent years. These new networks have attracted
many users and much press attention, along with the ire of
some powerful media corporations and trade organisations who
feel threatened by this alternative, bottom-up mode of information
distribution. Some commentators see P2P networks as offering
a significantly more 'democratic', perhaps even 'anarchic',
information topography and engendering new forms of online social
structures completely lacking in central points of organisation.
P2P breaks down the dominant information distribution paradigm
on the Internet, the client-server model of the Web [1].
P2P
networks are, of course, most popular for sharing mp3 music
files and much of this interaction involves the 'trading'
of copyright materials or 'content'. As such these networks
are a key component of the so called 'darknet', an informal
cluster technologies and communities for users to share digital
content [2]. The bastions of the media industries,
most particularly the Recording Industry Association of America
(RIAA), have attempted to choke-off the development and use
of P2P networks, by various means, as they see them simply
as conduits for wholesale digital theft [3].
P2P network topologies emerge spontaneously
from a multitude of individual actions - users simply connect to
the P2P network when they like and leave when they like . The networks
are typified by their lack of any centralised mechanisms for control,
storage or exchange. Consequently, P2P network structures evolve,
second by second, depending on which users are connected. The users
provide all the necessary infrastructure to the network - the hard-disk
storage, the processing cycles, the bandwidth and, of course, the
vital information content. In the world of P2P the users are both
the providers and the consumers. Unlike other information sharing
networks, such as gopher or WWW, P2P networks are genuine users'
networks: they have no external existence beyond those people who
are on the network at a given time. Clay Shirky has argued that
the key distinguishing feature of P2P networks is the shift in power
to the 'edges' of the Internet, as they are "leveraging previously
unused resources, by tolerating and even working with the variable
connectivity of the hundreds of millions of devices that have been
connected to the edges of the Internet in the last few years" [4].
Users form their own information space which can be immense in size,
although they are only ever aware of, and concerned, with their
immediate neighbourhood of peers.
Thedevelopment
of P2P protocols, and the free software applications used
to browse the resulting networks, has been an area of great
creativity in the last couple of years, sparked in large measure
by the runaway success of Napster, first released in the summer
of 1999. Although Napster is no more, it has spawned a growing
number of other P2P networks, such as Kazaa, Gnutella
and FreeNet [5]. The particular topological
characteristics of these different network spaces (especially
the ways in which they propagate queries and responses across
the network) vary depending on the exact P2P protocol design
employed, but they are all ad-hoc and fluid, linking together
multitudes of PCs on the edges of the Internet. Of course,
many of the underlying concepts of fully distributed networks,
where all nodes are peers and co-operatively share the overheads
of running the network, can be traced back to well before
the Napster- inspired, mp3 file-sharing boom of the last few years.
For example, peer network structures have long been a popular means
of structuring collaboration systems and instant messaging:
so-called person-to-person networks. In many ways, contemporary
P2P developments and growth are commensurate with the original
Internet concept of co-operating networks without a centre.
They are also a classic example of a 'disruptive technology',
that is seen as threatening to many entrenched interests but
also offer huge potential for innovation and overall market
growth [6].
The social
networks that form the fabric of our lives are structured
by space and time. P2P can fundamentally be seen as social space
and as such it structured by topological relations in space and
time of its users. Yet, the complex time-space topologies of
P2P networks, like Gnutella, are never normally apparent to
users, being hidden from view behind simple interfaces. After
all, users do not need to be able to see the structure of
the network to use it. But what would the time-space structures
look like if the interface became somehow transparent, thereby
revealing the fluctuating patterns of nodes and links as the
network evolves? How might one map the time-space structures
of P2P networks? A new application, called Minitasking,
provides one interesting answer [7].
Minitasking is
a visual client for browsing the Gnutella network, released in
April 2002. It provides a very different interface to P2P network
spaces compared to the norm. According to the readme file that
comes with the Minitasking, its aim is to give users "…a
visual manifestation of the properties of dynamic and temporarily
created networks and introduces transparency to the exchange
of data and network instability." The Gnutella network
is mapped by Minitasking using the notion of a visual
timeline with new nodes being added as they are encountered.
The end result does not look much like a conventional network maps,
being more like a growing necklace of beads. Yet Minitasking's
visualisations are strangely compelling, showing us the time-space
'bubbles' of the local Gnutella network neighbourhood around
one's machine. It is fascinating to watch the ebbs and flows
of queries and replies that pop up on the map.
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A screenshot of Minitasking
showing a fragmentary view of a small part of the Gnutella
network.
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Minitasking
was created by Schoenerwissen, an artistic research
and design group of Anne Pascual and Marcus Hauer, in Berlin.
It comes very much from the tradition of innovative net.art
type software, and should be interpreted in terms of experimentation
rather than efficiency; as the README says "… usage is
intended to depend more on chance than on routines". Hauer
and Pascual both studied media design and sciences at the
Academy of Media Arts in Cologne going onto form Schoenerwissen
in 1998. A literal translation of the German word schoenerwissen
means 'more beautiful knowledge' and Map of the Month
asked them a few questions, via email, to find out more about
the way Minitasking maps Gnutella.
"Our
objective", Hauer and Pascual explain, "was to show the 'invisible'
elements of data processing, to reintroduce technological elements
like a protocol in the use of software as a way to adopt the dynamics
and structure of networks." The limits and boundaries of the
Gnutella protocol forced them to work with the most undetermined
parts of the network, the temporal flow of space. This led them
to conceive and build "… a new form of the software and
we reshaped our vision to produce not only a visual interface, but",
following the ideas of media theorist Pit Schultz, "...to get
rid of usability in favour of visibility." They focused on the
functionality of the Gnutella P2P protocol and designed a very novel,
and very minimalist, visual front-end to it.
The
interface of Minitasking is a single large, dynamic map,
which displays the evolving relationships of Gnutella nodes on the
network, along a single growing timeline. Because of the nature
of the Gnutella network protocols, one can never get a complete
map, but can only see the structure viewed from one's own particular
vantage-point in virtual time and space. Minitasking represents
the active nodes it encounters in the local Gnutella neighbourhood
as bubbles that vary in size and colour depending on the number
of files they are sharing. The transparency of the colour of the
circle gives an indication of distance away from one's own vantage-point
- that is, a topological distance measured in network hops. So,
the lighter the circular bubble, the further 'away' it is. When
a mouse passes over a bubble, a pop-up displays useful data on the
node like IP address, number of files and hop distance. When you
submit a query to Gnutella, via Minitasking, the colour-coded
matches are shown in another bubble. Double-clicking on a file of
interest will start them downloading. The social nature of Gnutella
is also apparent in Minitasking as you can see the 'voices'
of other users in terms of queries they are making. These incoming
queries are themselves revealing in the oftentimes specific and
highly specialised content being sought after.
Other analysis and views of Gnutella |
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While
there have been several research projects interested in the
quantitative measurement and analysis of the structural properties
of Gnutella network [8], it would be fair to say no
one knows much about what is going on inside the P2P network
as a whole, and over time. However, it seems quite likely
that P2P network spaces are being intensively monitored, and
perhaps visually mapped, by corporations and trade bodies
like RIAA. Some activists suspect that the media industries,
and people working directly and indirectly for them, are forcibly
trying to change the formulation of P2P space to make it less
useful through, for example by deliberate 'pollution' with
multiple fake files and floods of false queries. Indeed, controversially
RIAA has been seeking new laws from U.S. Congress to give
content copyright holders the right to P2P networks and users
machines.
A One of the major
concerns with P2P networks like Gnutella has been their ability
to scale capacity, in an efficient manner, to cope with many
millions of users. This 'scaling' issue is further compounded
by concerns that P2P is especially prone to 'selfishness'
as users of the network are not carrying equal overhead loads, with
many wanting to 'take' without 'giving' in return. As researchers,
Eytan Adar and Bernardo A. Huberman found in their empirical
study of a day in the life of Gnutella in 2000, "… we established
that almost 70% of Gnutella users share no files, and nearly
50% of all responses are returned by the top 1% of sharing
hosts" [9]. Clearly, the network is not as evenly distributed
as the ideals of P2P would suggest.
There are many possible ways to map P2P
network structures. Beside Minitasking, the most notable
visualisation work was the Gnutellavision project undertaken in
2001 by Ka-Ping Yee, Danyel Fisher, and Rachna Dhamija, at University
of California Berkeley, producing interesting radial radar maps
of Gnutella [10]. There is still scope to try to undertake
a more comprehensive mapping of the whole Gnutella network space.
Being able to
see and understanding networks, is increasingly important.
Many aspects of the human and physical world can be modelled as
networks. Mapping the topological structure of a network, along
with understanding the behavioural rules of how individual nodes
become linked, provides a powerful explanation of the underlying
processes at work. Going way beyond P2P networks on Internet,
a number of scholars have advanced claims that networks are
keys to explaining much of the complexity of the world that
has not been easily understood with more traditional formulations.
One
of the leading researchers developing new theories of network
structure is the physicist, Albert-László Barabási,
who runs a research group at the University of Notre Dame
studying them. In his recently published book, Linked,
he convincingly argues for the explanatory power of a "new
science of networks" in a wide range of social, economic,
technological and biological realms [11]. As Barabási says,
"Today we increasingly recognize that nothing happens in
isolation. Most events and phenomena are connected, caused
by, and interacting with a huge number of other pieces of
a complex universal puzzle. …. We have come to grasp the importance
of networks." Most significantly, Barabási goes
onto argue that research must begin to move beyond just looking
at network structure to consider the actual dynamic processes
that the network supports, to begin to model what actually
flows over the links; "Networks are only the skeleton of complexity,
the highways for the various processes that make our world
hum." I would argue that part of the innovative significance
of Minitasking is that it tries to go beyond topology to map
out spatio-temporal patterns of traffic.
In
the realm of the ‘big theories’ for understanding society and the economy,
the noted social theorist Manuel Castells has used the concept of networks
to explain the changing dynamics of the world through globalisation and the
information revolution. In The Rise of the Network Society
[12], Castells argues powerfully that “… as a historical
trend, dominant functions and processes in the information age are increasingly
organized around networks. Networks constitute the new social morphology
of our societies, and the diffusion of networking logic substantially modifies
the operation and outcomes in processes of production, experience, power
and culture” (page 469). Clearly Gnutella is but a minuscule part of
the whole Network Society.
So
what can we discern of Gnutella’s time-space structure from Minitasking?
“What you see is not a network!” according to when asked about what
can one learn from observing Minitasking time-space maps of Gnutella. “The
potential of a Minitasking maps is not to provide the ‘perfect’ view of the
Gnutella network”, say Pascual and Hauer, “but to point the attention
to obscure details by observing them for a while.” Although one suspects
that others, probably with less benign motives will try to survey and map
out P2P space with much great precision and clarity.
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