I want to know about IEEE 802.3 completely including benefits and constraints of using it?
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25 meters
Answer:
Explanation:
This section discusses the development and evolution of Ethernet technologies as defined by both individual members of the industry and the IEEE.
The Evolution of Ethernet
Xerox Corporation usually receives credit for inventing Ethernet. However, Xerox actually acquired the original technology (then known as Aloha Net) in the 1970s from the University of Hawaii. Xerox then joined with DEC and Intel to develop the earliest Ethernet standard, called Version 1, which it released in 1980. The three companies released a follow-up standard, Ethernet Version 2, in 1982.
In the mid-1980s, the IEEE 802 committee adopted Ethernet as the 802.3 standard. All current and future development on Ethernet technologies ostensibly builds on this base standard.
Since its inception, Ethernet has become the most popular LAN standard used throughout the world.
Ethernet Versus IEEE 802.3
It is important to note that Ethernet is not the same as the IEEE 802.3 implementations, and the terms should not be used interchangeably (although they sometimes are). Whereas Xerox, DEC, and Intel developed Version 1 and Version 2 with somewhat similar parameters, the IEEE committee added several features that gave its standard expanded capabilities not shared with its predecessors.
Table 3.1 provides an overview of the similarities and differences between the three implementations.
Table 3.1 Ethernet Versions 1, 2, and IEEE 802.3
Version 1
Version 2
IEEE 802.3
Data Link layer architecture
Includes Ethernet_II frame (the de facto industry frame to carry IP traffic over Ethernet LANs)
Adds jabber control (or jabber inhibit) to detect and disable faulty transceivers
Delivered data at 10Mbps as linear bus topology
Delivers data at 10Mbps as linear bus topology
Expands physical topology support to star configurations
Could use only thick coaxial media
Can use only thick coaxial media
Adds media types such as thin coaxial, fiber, and twisted pair
Used unbalanced signaling with ground as reference point (susceptible to noise and EMI)
Uses balanced signaling
1995 enhancements provide 100Mbps transfer rates (802.3u)
Did not support Signal Quality Error (SQE) (also known as heartbeat), so more difficult to detect collisions
Adds SQE
Supports SQE but is only necessary with external transceivers
Figures 3.1 and 3.2 show examples of unbalanced and balanced signaling.
Figure
3.1 Unbalanced signaling varies voltage levels between 0 (referenced by ground) and +5 volts to represent data.
Figure
3.2 Balanced signaling uses positive and negative voltage levels to represent data.
The unbalanced signaling method used in Version 1 of the Ethernet specification simply uses the presence or lack of voltage to represent data. This type of signaling makes transmissions highly susceptible to outside interference. Ethernet Version 2 improved the signaling method by implementing balanced signaling, representing data through positive and negative voltage changes using 0 or ground as a common reference point. This approach diminishes the effects of interference on transmissions, improving signal quality.
General Ethernet Operation
The IEEE 802.3 specification defines the general operation, components, and distance limitations of Ethernet. They are as follows:
Defines all Data Link and Physical layer components, functions, channel access method, and operations.
Provides vendors with rules to follow when implementing or developing Ethernet 802.3 LAN technologies.
Is based on the IEEE standard known as 10Base5, which all other 802.3 standards follow with minor variations.