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The Second Internet


various things and/or monitor traffic. They also typically include support for monitoring or control using
SNMP (Simple Network Monitoring Protocol). Very advanced switches have the ability to configure
VLANs (Virtual LANs), which allow you to effectively create multiple sub-switches that are not connected
together.
3.2 – RFCs: The Internet Standards Process
Anyone studying the Internet, or developing applications for it, must understand the RFC system. RFC
stands for Request For Comments. These are the documents that define the Internet Protocol Suite (the
official name for TCP/IP) and many related topics. Anyone can submit an RFC. Ones that are part of the
Standards Track are usually produced by IETF (Internet Engineering Task Force) working groups. Anyone
can start or participate in a working group. Submitted RFCs begin life as an Internet Draft, each of which
has a lifespan of six months or less. Most drafts go through considerable peer review, and possibly
several revisions, before they are approved, are issued an official number (e.g. 793) and become part of
the official RFC collection. There are other kinds of documents in addition to the Standards Track,
including information memos (FYI), humor (primarily ones issued on April 1) and even one obituary, for
Jon Postel, the first RFC Editor and initial allocator of IP addresses, RFC 2468, “I Remember IANA”,
October 1998. There is even an RFC about RFCs, RFC 2026, “The Internet Standards Process, Revision 3”,
October 1996. That is a good place to start if you really want to learn how to read them.
The Internet standards process is quite different from the standards process of ISO (The International
Standards Organization) that created the OSI network specification. ISO typically develops large,
complex standards with multiple 4 year cycles, with hundreds of engineers and much political wrangling.
This was adequate for creating the standards for the worldwide telephony system, but is far too slow
and hidebound for something as freewheeling and rapidly evolving as the Internet. The unique
standards process of the IETF is one of the main reasons that TCP/IP is now the dominant networking
standard worldwide. By the time OSI was specified, TCP/IP was already created, deployed, and being
revised and expanded. OSI never knew what hit it.
Learning to read RFCs is an acquired skill, one that anyone serious about understanding the Internet,
and most developers creating things for it, should master. There are certain “terms of art”, like the
usage of MUST, SHOULD, MAY and NOT RECOMMENDED that are precisely defined and used. As an
example, the IPv6 Ready Silver (Phase 1) tests examine only the MUST items from relevant RFCs, but the
IPv6 Ready Gold (Phase 2) tests also examine all of the SHOULD items.
RFCs are readily available to anyone for free. Compare this to the ISO standards, which can cost over
$1000 for a complete set of “fascicles” for something like X.500. Today you can obtain RFCs easily in
various formats by use of a search engine such as Google or Yahoo. The “official” source is the URL:
http://www.rfc-editor.org/rfc/rfcXXXX.txt
(where XXXX is the RFC number)
There is also an official RFC search page, where you can search for phrases (like “TCP”) in different
tracks, such as RFC, STD, BCP or FYI, or all tracks. You can retrieve the ASCII or PDF versions. It is at:
https://www.rfc-editor.org/rfcsearch.html
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