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Tham khảo tài liệu 'protocols and transmission theory', công nghệ thông tin, quản trị mạng phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Protocols Explained • Protocol History • Signalling – Frequency vs. Bit Rate Transmission and Protocol Theory 1 Protocol History • Ethernet conception • StarLAN • Token Ring • Cell vs. Packets – ATM vs. Ethernet • Ethernet comes of age Transmission and Protocol Theory 2 Protocol History • Born from the original Aloha Network in 1972 • Xerox, who pioneered the first PC with a GUI commission Bob Metcalfe to develop networking from their ALTO computers to Arpanet • The breakthrough was a device that could listen before transmitting, which allowed for full utilization of the bandwidth speed (2.94Mbps) • In 1977 they were issued the patent on CSMA/CD (Carrier-Sense Multiple Access with Collision Detection) Transmission and Protocol Theory 3 Protocol History • The key principle behind Ethernets success was not it’s speed early on or the way it transmitted within a network, but Metcalfe’s vision to have a standardized platform that WAS NOT proprietary • This was pushed further by joint efforts between Intel, DEC and Xerox in the late 70’s through to the early 80’s • Simultaneously the IEEE began working on standardizing protocol developments, starting with Ethernet, as Xerox continued to turn it’s patents over to them in an effort to drive global adoption with a standard platform Transmission and Protocol Theory 4 Protocol History • Metcalfe and others broke off on their own to form 3COM in 1979 • They released their first TCP/IP transceivers for UNIX a full 18 Months before the IEEE standard • The 3C100 Transceivers were being produced for DEC, Intel and Sun Microsystems • Both Apple and IBM were approached in an effort to push networking for the developing PC market • Apple said yes, but IBM said no because of their own Token Ring developments Transmission and Protocol Theory 5 Protocol History • 3COM, without the cooperation of IBM, decided to produce the highly successful ISA EtherLink adaptors for IBM PC’s • This was highly cost effective at the time ($950 USD) and .
