However, Token Bus was not particularly well suited for fiber transmission and experienced
latency even at small loads.
Token Ring, mainly adopted by IBM, also had similarly attractive features. In addition,
it could also be deployed in a ring topology and supported arbitrarily long frames
efficiently (unlike the Token Bus), but like the Token Bus, Token Ring suffered from
latency (as do all token passing schemes).
As more powerful workstations began to proliferate on LANs, these technologies
became inadequate from the standpoint of scale, reliability, and bandwidth; FDDI
25 Other standards bodies such as the IETF have also been active but most of the work on LAN Ethernet
was done in the IEEE whose focus has been on the PHY and Data Link-layer
14 Chapter 1
was developed in the mid-1980s as a response to these shortcomings. FDDI was also
token-based (in fact, it uses Token Ring as its basis) and supported 100-Mbps bandwidth
using fiber optic cable deployed in a dual ring configuration. Traffic on each
of the rings, referred to as the primary and secondary, flowed in opposite directions.
TABLE 1.1 Development of Ethernet: A Look at the (IEEE) Standardization Efforts
Year Standard Brief Description
1973 Ethernet Invented 2.
Pages:
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115