The advent of electronic mail (email) was a critical component for user-to-user digital communication. With the introduction of the global Internet, billions of users have access to the fastest, most economical form of communication in all of civilized history—as of this writing, about 2.2 billion people or 1/3 of the world’s population.
The first electronic mail system dates back to the 1970s, as part of the Advanced Research Projects Agency Network (ARPANET), the world’s first packet switching network design.
From circuit switching to packet switching
Throughout the first half of the 20th Century, all communications, both voice and data were handled through circuit switching. Circuit switching is best explained by referencing our early telephone system, where communications were handled by allocating and routing each individual message through a series of designated circuits and connected stations (telephones or computers) stretching between point A and point B; the downside was “designated”. Packet switching revolutionized our communications, allowing both voice and data to be grouped into datagrams, or data packets within a computer network system, transmitting our communications simultaneously from network to network, using a single communications link.
From FTP to SMTP (protocols)
In addition to our migration from circuit switching to packet switching, protocols also improved. The older File Transfer Protocol (FTP) was replaced by the new standard Simple Mail Transfer Protocol (SMTP) in the early 1980s. The SMTP not only sped up communications, but included more advanced delivery parameters, changing email communications from simple text messages to the look, feel and function of our 3-deminsional snail mail from a virtual post box. All email messages we sent or received had a standard format, including an envelope with identifying data, a header (addressee and subject) and body text. Today, and three decades later, virtually all emails still use the SMTP transfer protocol worldwide.
From text-only to MIME
Early email messages were text-only, traditionally small 7-bit ASCII files of data, much like the text messaging capabilities on our wireless phones. Advanced Internet standards were introduced for email formats expanding their capabilities from text-only messages to Multipurpose Internet Mail Extensions (MIME). This new standard not only dramatically changed the content format of our emails, but allowed us the capability for attachments, and continues to serve in an important role in our communication protocols over the global Internet. Virtually all digital communications today are transmitted in MIME format, whether an actual email message or something else, keeping our communications across the globe synchronized in a format we can all agree on, access, follow and understand.
ARP/InARP · NDP · Tunnels ( L2TP ) · PPP · Media access control ( Ethernet · DSL · ISDN · FDDI )