In the current P2P world, torrenters and the like are discovering that a recent Windows-update – included in XP service pack 3, and Vista – alters the tcpip.sys file that governs Windows tcp behavior to limit users to just 10 ‘half open‘ connections at any one time. This could be a response to the concerns raised by cable ISP’s like Comcast that’s DOCSIS-based networks break down when clients use over-multitudinous connections. Needless to say, as the word spreads, workarounds to undo MS’s changes are proliferating.
A Mar 17 article in BetaNews notes the aptly-timed announcement that, for the forthcoming Windows 7, Microsoft is contemplating adding such features as metered connections, distributed hash tables, and something called ‘green P2P’. The article notes that Windows Vista already includes an IPv6-based P2P-enabling technology known as Teredo.
From the article:
Teredo was designed in 2003, and later implemented in Vista, as a novel approach for moving network traffic where packets use IPv6 protocol and addresses, across a firewall that uses an IPv4 network address translator. NAT is the most common method for any firewall to mask computers within a subnet. Each of those computers is given an IPv4 link-local address, usually beginning with the prefix 192.168.x.x.
But with Windows Server 2008, which premiered late last month, utilizing IPv6 as a default alternative addressing scheme for the first time, Vista had to be ready to support it as well. So rather than tunnel underneath the firewall, Teredo builds a kind of for-the-nonce P2P bridge over it, while still letting the NAT do the job of forwarding packets to their final IPv4 link-local destinations.
Another of the new technologies being considered for Windows 7 is given the timely name “Green P2P.” It’s a power management system for letting “PCs go to sleep and wake up only when addressed” over a P2P network.
Microsoft is also thinking about adding metered connections so as to reduce network “chattiness” over P2P links.
As another improvement, Microsoft is contemplating distributed hash tables (DHT), both for enterprise data centers and broad Internet use, said Tan. DHTs are aimed at supporting scalability on P2P and CDN networks to very large numbers of nodes.
The initial nickname of the Teredo tunneling protocol was shipworm. The idea was that the protocol would pierce holes through NAT devices, much like the shipworms bore tunnels through wood. Shipworms are responsible for the loss of very many wooden hulls, but Christian Huitema in the original draft noted that the animal only survives in relatively clean and unpolluted water; its recent comeback in several Northern American harbors is a testimony to their newly retrieved cleanliness. Similarly, by piercing holes through NAT, the service would contribute to a newly retrieved transparency of the Internet.
Christian Huitema quickly changed the name to Teredo to avoid confusion with computer worms. Teredo navalis is the Latin name of one of the best known species of shipworm.