1. CISCO NETWORKING ACADEMY Chabot College ELEC 99.05 Ethernet & 802.3

2. CISCO NETWORKING ACADEMY Network Technologies A network technology is a “set of rules” that describes Layer 1 & 2. Data Link Layer Physical Layer How do I access the wire (media)? What kind of wire (media) do I use? Network Layer

3. CISCO NETWORKING ACADEMY Common LAN technologies Ethernet is the simplest, cheapest, and (therefore) most popular LAN technology.

4. CISCO NETWORKING ACADEMY Ethernet and TCP/IP Ethernet & TCP/IP are the most pervasive LAN protocols, and are often used together. Data Link Layer Physical Layer Network Layer Session Layer Transport Layer Presentation Layer Application Layer TCP/IP Ethernet

5. CISCO NETWORKING ACADEMY 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

6. CISCO NETWORKING ACADEMY Origins of Ethernet DIX released their second and final standard in 1982. –DIX Ethernet Version 2.0 or, –Ethernet II

7. CISCO NETWORKING ACADEMY Meanwhile... The IEEE maintains a committee that is concerned with Networking Standards. The committee, made up of working groups, is called 802.

8. CISCO NETWORKING ACADEMY The Working Groups 802.1 802.2 802.3 802.4 802.5 802.6 802.7 802.8 802.9 Networking Overview and Architecture Logical Link Control Ethernet Token Bus Token Ring MANs Broadband Fiber Optic Isochronous LAN...and more!

9. CISCO NETWORKING ACADEMY 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

10. CISCO NETWORKING ACADEMY 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

11. CISCO NETWORKING ACADEMY Ethernet and 802.3 Ethernet and 802.3 are often thought of as the same thing. Technically, they aren’t.

12. CISCO NETWORKING ACADEMY Ethernet & 802.3 Similarities At Layer 2, both standards describe: –CSMA/CD Media Access Method –logical “bus” topology

13. CISCO NETWORKING ACADEMY Ethernet & 802.3 Similarities At the physical layer, both standards allow: –coaxial cable –physical “bus” topology

14. CISCO NETWORKING ACADEMY 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)

15. CISCO NETWORKING ACADEMY Ethernet & 802.3 Differences At Layer 2, these standards describe different ways of organizing the frame header: PreambleDASALength 64 bits48 bits 16 bits Ethernet 802.3 frame with LLC PreambleDASAType 64 bits48 bits 16 bits Ethernet II (DIX standard)

16. CISCO NETWORKING ACADEMY 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

17. CISCO NETWORKING ACADEMY 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.