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FWD# 61159
Fri, 05 Aug 2005
Tim pointed me to an excellent article on Wikipedia describing BitTorrent. See also their page on Peer-to-peer in general.
Somewhere else (???) described BitTorrent as being different from other peer-to-peer applications because there is no inbuilt method for publishing, or searching for metadata. Publishing (announcing to the world that you have some files with particular names / descriptions / sizes / checksums ) and searching (the world being able to find the file you want and how to get it) are done using other tools such as Web servers, e-mail, or even embeded into games.
In some file-sharing schemes, a large number of users get together and share a number of files that is 10s, 100s or 1000s of the number of users. In contrast, with BitTorrent, a number (between 2 and 100,000) of users obtain the .torrent metadata for a single file (or indivisible bundle of files), and then get together in a specially-purposed swarm to spread just that file to all of them.
Comparing BitTorrent to normal Web operations, I think BitTorrent is most like a dynamic distributed caching proxy server cloud. You can't tell whether a file came from the original site, or from a proxy -- a local proxy, your ISP's proxy, a parent or peer of proxy the proxy you thought you were using, a front-end reverse proxy, a load balancer, ... Normal Web proxy networks are general purpose and need to be statically configured. BitTorrent proxy clouds are single file, highly dynamic and self-organising (with hints from the tracker).
A BitTorrent proxy cloud operates differently in that a client will up/download parts of the a file (and cryptographically check those parts), rather than a Web proxy which likes to deal in whole files (and blindly trusts the received content).
Brian Dessent writes
It takes a great deal of bandwidth and server resources to distribute files that are large or very popular, or both. The concept of mirrors partially addresses this shortcoming by distributing the load across multiple servers. But it requires a lot of coordination and effort to set up an efficient network of mirrors, and it's usually only feasible for the busiest of sites. ...
BitTorrent is closest to Usenet, in my opinion. It is best suited to newer files, of which a number of people have interest in.
PS. Microsoft are working on something similar called Avalanche
The code-named research project "Avalanche" studies how to enable a cost effective, internet scalable and very fast file distribution solution (e.g. for TV on-demand, patches, software distribution). Such an approach leverages desktop PCs to aid in the distribution process, relieving congested servers and network links from most of the traffic.
Will peer-to-peer be banned if Microsoft provide it and want you to use it? (Windows File and Print is peer-to-peer already.)
InternetNZ unveils software for Enum
ENUM PUA Prototype Software Release
InternetNZ Announces the release of ENUM Personal User Agent Prototype software under Open Source BSD Licence.
"Personal User Agents (PUA) are software programs which act like firewalls; automatically filtering requests for ENUM contact information and deciding what information to release and how incoming calls will be directed based on rules that look at the inbound identity of the caller. This protects the consumer from address harvesting or privacy breaches.
http://www.internetnz.net.nz/public/enum/pua/README.txt
... Installation The system integrates with Asterisk - the Open Source PBX! (www.asterisk.org). ...
My guess is that to filter requests for ENUM contact information and to control routing of calls, the information must be stored locally, and not publised in the DNS (apart from some generic "send everything to the gateway box" info).
Memo to mainstream media: You don't get to blog
The DNA of blogging is a complicated matter that touches on being outside voices and taking personal control of the media. But at minimum the DNA of blogging has to do with distributing the conversation. Contrary to that, the DNA of mainstream media to date is all about dominating the conversation.
... in the pure sense a big part of blogging involves the voices of people who don't have a publishing/broadcasting aparatus at their disposal and don't have the institutional restraints of a media company.
What Business Can Learn from Open Source
Another interesting Paul Graham essay, about blogging, "amateurs" + aggregators v. "professionals" + channels, startup investor-founder relationships v. paternalistic employer-employee relationships.
So these, I think, are the three big lessons open source and blogging have to teach business: (1) that people work harder on stuff they like, (2) that the standard office environment is very unproductive, and (3) that bottom-up often works better than top-down.