Usenet is a set of protocols for generating, storing and retrieving news "articles" (which resemble Internet mail messages) and for exchanging them among a readership which is potentially widely distributed. These protocols most commonly use a flooding algorithm which propagates copies throughout a network of participating servers. Whenever a message reaches a server, that server forwards the message to all its network neighbors that haven't yet seen the article. Only one copy of a message is stored per server, and each server makes it available on demand to the (typically local) readers able to access that server. Usenet was thus one of the first peer-to-peer applications, although in this case the "peers" are themselves servers that the users then access, rather than the users themselves being peers on the network. However, the end users connects to the server of the service provider and are therefore not interacting with each other, opposed the common meaning of a peer-to-peer network.
RFC 850 was the first formal specification of the messages exchanged by Usenet servers. It was superseded by RFC 1036.
In cases where unsuitable content has been posted, Usenet has support for automated removal of a posting from the whole network by creating a cancel message, although due to a lack of authentication and resultant abuse, this capability is frequently disabled. Copyright holders may still request the manual deletion of infringing material using the provisions of World Intellectual Property Organization treaty implementations, such as the U.S. Online Copyright Infringement Liability Limitation Act.
On the Internet, Usenet is typically on TCP Port 119.
No comments:
Post a Comment