Proprietary Networks And Internetworking: 1972"1980

RPAnet host, one had to be actually attached to another ARPAnet IMP. In the early to ccie online training, additional stand-alone packet-switching networks besides ARPAnet came into being.

ALOHANet, a microwave network linking universities on the Hawaiian islands [Abramson 1970], as well as DARPA’s packet-satellite [RFC 829] and packet-radio networks [Kahn 1978]
Telenet, a BBN commercial packet-switching network based on ARPAnet technology
Cyclades, a French packet-switching network pioneered by Louis Pouzin [Think 2007]
Time-sharing networks such as Tymnet and the GE Information Services network. among others, in the late 1960s and early 1970s [Schwartz 1977]
IBM’s SNA (1969"1974), which paralleled the ARPAnet work [Schwartz 19771

The number of networks was growing. With perfect. ccie sp we can see that the time was ripe for developing an encompassing architecture for connecting networks together. Pioneering work on interconnecting networks (under the sponsorship of the Defense Advanced Research Projects Agency (DARPA), in essence creating a network of networks, was done by Vinton Cerf and Robed Kahn [Cerf 1974]; the term internetting was coined to describe this work.

These architectural principles were embodied in TCP. The early versions of TCP, however, were quite different from today’s TCP. The early versions of TCP combined a reliable in-se4uence delivery of data via end-system retransmission (still part of today’s TCP) with forwarding functions (which today are performed by IP). Early experimentation with TCP, combined with the recognition of the importance of an ccie voice torrent, non-flow-controlled, end-to-end transport service for applications such as packetized voice, led to the separation of IP out of TCP and the development of the. UDP protocol. The three key Internet protocols that we see today"TCP, UDP, and IP"were conceptually in place by the end of the 1970s.

In addition to the DARPA Internet-related research, many other important networking activities were underway. In Hawaii, Norman Abramson was developing ALOHAnet, a packet-based radio network that allowed multiple remote sites on the Hawaiian islands to communicate with each other. The ALOHA protocol [Abramson 1970] was the first multiple-access protocol, allowing geographically distributed users to share a single broadcast communication medium (a radio frequency). Metcalfe and Boggs built on Abramson’s multiple-access protocol work wh5n they developed the Ethernet protocol [Metcalfe 1976] for wire-based shared broadcast networks. Interestingly, Metcalfe and Boggs’ Ethernet protocol was motivated by the need to connect multiple PCs, printers, and shared disks [Perkins 1994]. Twenty-five years ago, well before’the PC revolution and the explosion of networks, Metcalfe and Boggs were laying the foundation for today’s PC LANs. Ethernet technology represented an important step for internetworking as well. Each Ethernet local area network was itself a network, and as the number of LANs proliferated, the need to internetwork these LANs together became increasingly important. We’ll discuss Ethernet, ALOHA, and other LAN technologies.