The Second Internet
While all of this was going on, ISO (the International Organization for Standardization) in Europe was
creating a very thoroughly engineered suite of network protocols called Open System Interconnect
(OSI), or more formally, X.200 (July 1994). This is where the famous “seven layer” network model comes
from (TCP/IP is really a “four layer” model, which has caused no end of confusion among young network
engineers). At one point the U.S. government decided to officially adopt OSI for its networking (this was
called GOSIP, or Government Open Systems Interconnection Profile, defined in FIPS 146-1, 1990).
Unfortunately, OSI was really more of an academic specification, not a real working network system, like
TCP/IP was. After many years, GOSIP was finally abandoned and TCP/IPv4 was deployed, but GOSIP’s
legacy has hindered the adoption of IPv6 in the U.S. (“here we go again – GOSIP Part 2!”). X.400 e-Mail
and X.500 directory systems were built on top of OSI, and will not run on TCP/IP without substantial
compatibility layers. One small part of X.500 (called X.509) was the source of digital certificates and
Public Key Infrastructure, still used today. LDAP was an attempt to create an X.500-like directory system
for TCP/IP based networks. That’s about all that is left of the mighty OSI effort today, outside of
Computer Science textbooks and Cisco Press books.
2.2.3 – E-Mail Standardization
By this time, essentially all computer vendors had standardized on TCP/IP, but there were still a lot of
competing standards for e-Mail, including Microsoft’s MS-Mail, Lotus’s cc:Mail, and MCI Mail. The
Internet folks used a much simpler e-mail standard called SMTP (Simple Mail Transfer Protocol). It first
became the connecting backbone between various e-Mail products (everyone had their e-Mail to SMTP
gateways, so users could exchange messages across organizations). Soon, everyone started using SMTP
(together with POP3 and later IMAP) all the way to the end-user. Today virtually all e-Mail worldwide is
based on SMTP and TCP/IP.
2.2.4 – Evolution of the World Wide Web
Several other Internet applications evolved, including WAIS (Wide Area Information Server, for storing
and retrieving documents) and Archie (the very first search engine). In turn, these efforts were merged
with the idea of HyperText (documents with multi-level links) and evolved into HTML (HyperText
Markup Language) and HTTP (HyperText Transfer Protocol). The World Wide Web was off and running.
The first web browser and web server were created at the National Center for Supercomputing
Applications (NCSA) at the University of Illinois, Urbana-Champaign campus. The people that created
those software projects (primarily Marc Andreessen and Eric Bina) were soon hired by Jim Clark, one of
the founders of Silicon Graphics, to start NetScape, one of the most successful companies in the First
Internet. They created a new and more powerful web server (NetScape Web Server) and web browser
(NetScape Navigator). Interestingly enough, the original browser created by Andreessen at NCSA later
became the starting point for Microsoft’s Internet Explorer web browser.
2.3 – And That Brings Us Up to Today
That pretty much brings us up to the present day where the entire world has standardized on TCP/IPv4
protocols for both LANs (Local Area Networks) and WANs (Wide Area Networks). MPLS is not a