“Control of thought is more important for governments that are free and popular than for despotic and military states. The logic is straightforward: a despotic state can control its domestic enemies by force, but as the state loses this weapon, other devices are required to prevent the ignorant masses from interfering with public affairs, which are none of their business…the public are to be observers, not participants, consumers of ideology as well as products.” – Noam Chomsky PUBLIC FORUMS “Only a large-scale popular movement toward decentralization and self-help can arrest the present tendency toward statism… A really efficient totalitarian state would be one in which the all-powerful executive of political bosses and their army of managers control a population of slaves who do not have to be coerced, because they love their servitude. To make them love it is the task assigned, in present-day totalitarian states, to ministries of propaganda, newspaper editors and schoolteachers… The greatest triumphs of propaganda have been accomplished, not by doing something, but by refraining from doing. Great is truth, but still greater, from a practical point of view, is silence about truth.” – Aldous Huxley ATOMIZATION “It is not only the hostility of others that may prevent us from questioning the status quo. Our will to doubt can be just as powerfully sapped by an internal sense that societal conventions must have a sound basis, even if we are not sure exactly what this may be, because they have been adhered to by a great many people for a long time. It seems implausible that our society could be gravely mistaken in its beliefs, and at the same time, that we would be alone in noticing the fact. We stifle our doubts, and follow the flock, because we cannot conceive of ourselves as pioneers of hitherto unknown difficult truths. It is for help in overcoming our meekness that we can turn to the philosopher.” – Alain de Botton RSS FEEDS “Our personal consumer choices have ecological, social, and spiritual consequences. It is time to re-examine some of our deeply held notions that underlie our lifestyles.” – David Suzuki
PEER TO PEER (P2P)
Centralized P2P networks rely on services of servers for indexing and finding content, like Napster. It distributes files between peers but file lookup relay on the server after a resource is located, request and reply process is between peers. Decentralized P2P networks rely on “supernodes”. It bases election of a supernode on node resources, so a node during join procedures doesn’t know if it will become the supernode. Kazza and Grokster are examples of “decentralized p2p networks”. “Pure P2P” is a network across which all nodes are equal, without servers or supernodes. It bases content lookup on some type of broadcast request or network limited flood. Gnutella is an example of “pure p2p” network architecture. All P2P networks in effect create de facto “logical overlay networks” so pure P2P is means all peers have the same authority and same functional potential. In any distributed system (such as a P2P network) there are trade-offs in terms of efficiency, security, scalability, robustness and decentralization. The fundamental difference between the two approaches you mention is that one prioritizes robustness, while the other prioritizes efficiency. A decentralized index approach is more robust (no single point of failure), but it is usually tricky to make it as efficient as a centralized approach. In terms of scalability, decentralized approaches have a bigger potential, but it is not trivial to ensure that a given decentralized system actually scales well from both a theoretical and a practical point of view. They advertise decentralized or pure P2P networks as robust “distributed networks”, usually at large-scale, without the weakness (or security risk) of relying on centralized limited authority service. But P2P is rarely “pure” centralized (represented by a traditional client-server architecture) – if you talk about centralized P2P approaches, it means hybrid systems. The most common hybrid uses the JOIN procedure and a META information data separation. The JOIN procedure is are used to establish node placement, changes in node status, parsing a new node entering the network or an existing node disconnecting. The newly entering node will often inform a starter node (already a member of the P2P network) to seed itself into the distribution. If a system is a large-scale network distributed over the Internet, then it is nearly impossible to use resource discovery algorithms to look for nodes in real-time – not least because of the associated messages cost. The solution is usually to maintain a list of nodes already on the network – mirrored for robustness. But it’s a solution that doesn’t scale when the number of nodes in the network increases and/or decreases rapidly in real-time. No pure P2P network can use the standard JOIN procedure. META information messaging protocol passes summary or header information about the data and peer(s) based on lookups maintained on multiple “centralized” (or well-known server entities). The META data will be a concise summary. It will be separated from the data intensive payload or content – the actual file being passed peer-to-peer. META information may include parameters like file size, availability, bandwidth, routing, authority, IP-addresses, latency windows, etc. Hybrids, after processing the META information, can then organize data transmission for the actual payload file or media stream (the most bandwidth intensive aspect, by far) using decentralized distribution, with a supernode or directly peer-to-peer. To have a truly pure decentralized P2P network, all node activity, peer handshaking and data exchange – including the META information and node JOIN – must be managed reliably without authoritative server systems. The pure P2P communication starts with initial broadcast process and then handshake process (in its entirety) between peers – concurrently informing the network “neighborhood” with up-to-date knowledge – each node concurrently informing and being informed. Exchange of content involves this speculative exchange of information about peer/node distribution and authorities (if apposite) followed by efficient establishment of the P2P exclusivity.
