General Computer Science 320201 GenCS I & II Lecture ... - Kwarc

That was almost all, but we close the connection (this is a telnet command)
quit
our terminal server (the telnet program) tells us
221 2.0.0 Service closing transmission channel
Connection closed by foreign host.
c○: Michael Kohlhase 349
Essentially, the SMTP protocol mimics a conversation of polite computers that exchange messages
by reading them out loud to each other (including the addressing information).
We could go on for quite a while with understanding one Internet protocol after each other, but
this is beyond the scope of this course (indeed there are specific courses that do just that). Here
we only answer the question where these protocols come from, and where we can find out more
about them.
Internet Standardization
Question: Where do all the protocols come from? (someone has to manage that)
Definition 512 The Internet Engineering Task Force (IETF) is an open standards organization
that develops and standardizes Internet standards, in particular the TCP/IP and Internet
protocol suite.
All participants in the IETF are volunteers (usually paid by their employers)
Rough Consensus and Running Code: Standards are determined by the “rough consensus
method” (consensus preferred, but not all members need agree) IETF is interested in
practical, working systems that can be quickly implemented.
Idea: running code leads to rough consensus or vice versa.
Definition 513 The standards documents of the IETF are called Request for Comments
(RFC). (more than 6300 so far; see http://www.rfc-editor.org/)
c○: Michael Kohlhase 350
This concludes our very brief exposition of the Internet. The essential idea is that it consists of
a decentrally managed, packet-switched network whose function and value is defined in terms of
the Internet protocol suite.
3.5.3 Basic Concepts of the World Wide Web
The World Wide Web (WWWeb) is the hypertext/multimedia part of the Internet. It is implemented
as a service on top of the Internet (at the aplication level) based on specific protocols and
markup formats for documents.
Concepts of the World Wide Web
Definition 514 A web page is a document on the WWWeb that can include multimedia
data and hyperlinks.
Definition 515 A web site is a collection of related Web pages usually designed or controlled
by the same individual or company.
a web site generally shares a common domain name.
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