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Chabot College. ELEC 99.05 Ethernet & 802.3. Network Technologies. A network technology is a “set of rules” that describes Layer 1 & 2. How do I access the wire (media)?. Network Layer. Data Link Layer. Physical Layer. What kind of wire (media) do I use?. Common LAN technologies.
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Chabot College ELEC 99.05 Ethernet & 802.3
Network Technologies • A network technology is a “set of rules” that describes Layer 1 & 2. How do I access the wire (media)? Network Layer Data Link Layer Physical Layer What kind of wire (media) do I use?
Common LAN technologies Ethernet is the simplest, cheapest, and (therefore) most popular LAN technology.
Application Layer Presentation Layer Session Layer Transport Layer Network Layer Data Link Layer Physical Layer Ethernet and TCP/IP Ethernet & TCP/IP are the most pervasive LAN protocols, and are often used together. TCP/IP Ethernet
Origins of Ethernet • developed at Xerox Palo Alto Research Center (PARC) in the early 1970s . • first standardized in 1980 by Digital, Intel, and Xerox (“DIX”). • DIX Ethernet version 1.0 or, • Ethernet I
Origins of Ethernet • DIX released their second and final standard in 1982. • DIX Ethernet Version 2.0 or, • Ethernet II
Meanwhile... The IEEE maintains a committee that is concerned with Networking Standards. The committee, made up of working groups, is called 802.
Networking Overview and Architecture 802.1 Logical Link Control 802.2 802.3 Ethernet 802.4 Token Bus 802.5 Token Ring 802.6 MANs 802.7 Broadband 802.8 Fiber Optic 802.9 Isochronous LAN The Working Groups ...and more!
The 802.3 Working Group • released first standard in 1983 • 10Base5 • released thinnet standard in 1985 • 10Base2 • released twisted pair standard in 1990 • 10Base-T • revolutionized networking
The 802.3 Working Group • released Fast Ethernet standard in 1995 • 100Base-X • released full-duplex standard in 1997 • no collisions • released Gigabit standard in 1998 • 1000Base-X
Ethernet and 802.3 • Ethernet and 802.3 are often thought of as the same thing. • Technically, they aren’t.
Ethernet & 802.3 Similarities • At Layer 2, both standards describe: • CSMA/CD Media Access Method • logical “bus” topology
Ethernet & 802.3 Similarities • At the physical layer, both standards allow: • coaxial cable • physical “bus” topology
Ethernet & 802.3 Differences • 802.3 not only specifies coaxial cable, but twisted pair and fiber as well. • 802.3 also specifies physical star topology. • IEEE Layer-1 specs, include: • 10Base-T (twisted pair, physical star) • 10Base2 (thinnet coax, physical bus) • 10Base5 (thicknet coax, physical bus) • 10Base-F (fiber, physical bus)
Ethernet II (DIX standard) Ethernet 802.3 frame with LLC 16 bits 16 bits 64 bits 64 bits 48 bits 48 bits 48 bits 48 bits Preamble Preamble DA DA SA SA Length Type Ethernet & 802.3 Differences • At Layer 2, these standards describe different ways of organizing the frame header:
Ethernet & 802.3 Compared • Ethernet II (DIX Ethernet) • old spec • CSMA/CD, simple frame format • coax bus only • 802.3 • constant new specs • CSMA/CD, more complex frame format • coax, fiber, twisted pair • star and bus
The Last Word • Most of the time, the term “Ethernet” is used to mean IEEE 802.3 • For the most part, Ethernet and 802.3 are used interchangeably, even though they are not really the same thing.