Module Ethernet Technology Ethernet the History u u

Module Ethernet Technology

Ethernet - the History u u u 1973 Development begins 1976 First paper on Ethernet published 1977 Ethernet is patented 1979 DEC, INTEL, and XEROX collaborate on Ethernet Version 1. 1980 Ethernet V. 1 is published 1980 Xerox ships first Ethernet 1982 Ethernet version 2 is published 1983 IEEE approves 802. 3 standard 1985 Ethernet is produces by more than 200 vendors 1985 Installed base exceeds 20. 000 Units 1992 -1994 Fast Ethernet / 100 Mbps/ Switching May 1996 Ethernet Technology Rev. 1. 00 Page 2

IEEE 802. 3 standards Protocols Layer 802 Internetworking Network 802. 2 Logical Link Control 802 Network Architecture Management 802. 3 Access Control 802. 4 802. 3 Token CSMA/CD Passing Bus 10 BASE-2 10 BASE-5 Logical Link 802. 5 Media Access 802. 6 Access Control Media Access Control 802. 5 Token Passing Ring 802. 6 Metro Area Network Physical Link 10 BASE-T 10 BASE-F May 1996 Ethernet Technology Rev. 1. 00 Page 3

Ethernet Access Method u CSMA/CD · Carrier Sense “Listen before trying to transmit - is the cable free? “ · Multiple Access “Many Stations are allowed to use the same media” · Collision Detect “Be aware of signal collisions - back off when detected” Signal 50 ohm Terminator Collision Signal 50 ohm Terminator Shared media ( bus ) Computer ‘earth’ May 1996 Ethernet Technology Rev. 1. 00 Page 4

Ethernet Frames Ethernet V. II Preample Sync 1010. . 10 11 (62 bits) (2 bits) DA (6 bytes) SA Type Data. . . (6 bytes) (2 bytes) FCS (padding) (4 bytes) (45 - 1500 bytes) MAC addresses IEEE 802. 3 Preample SFD 1010. . 10 10. . 11 (56 bits) (8 bits) DA (6 bytes) SA Length (6 bytes) (2 bytes) Data. . . FCS (padding) (45 - 1500 bytes) (4 bytes) MAC addresses May 1996 Ethernet Technology Rev. 1. 00 Page 5

Ethernet Transceiver u Physical Signalling u Collision Detect u SQE Test u Jabber Function LAN media Transceiver TX Wires RX Wires Collision Power ‘Drop’ cable to station (AUI Interface) May 1996 Ethernet Technology Rev. 1. 00 Page 6

10 BASE-5 ‘Yellow‘ Cable u Max. 500 m. Cable Segments u Max. 100 Stations per Cable Segment u 2. 5 m. between Transceivers u 50 Ohm terminator at each end 2. 5 m. Transceiver 50 ohm Terminator Computer ‘earth’ 50 ohm Terminator (IEEE 802. 3 media) Drop cable AUI interface May 1996 Ethernet Technology Rev. 1. 00 Page 7

10 BASE-2 “Cheapernet” Cable u Max. 185 m. Cable Segments u Max. 30 Stations per Cable Segment u Min. 0. 5 m. Distance between Stations u BNC Connectors used to attach stations u 50 Ohm terminator at each end 50 ohm Terminator BNC T Connector Build-in transceiver External transceiver Drop cable AUI interface May 1996 Ethernet Technology Rev. 1. 00 Page 8

10 BASE-T “UTP” Cable u Requires a Cabling Hub u Max. 100 m. from Station to Hub Star topology Cabling Hub (repeater) 100 m. Cable segments May 1996 Ethernet Technology Rev. 1. 00 Page 9

10 BASE-F Fiber Optic Cable u Noise Immune u No Ground Loops u Long Distance (up to 2 Km. ) u Stations connect to a Central Hub u Max. Two Stations per Cable Segment u Typically used for Inter-Hub Connectivity May 1996 Ethernet Technology Rev. 1. 00 Page 10

Intelligent structured wiring systems u Increased Flexibility u Improved Availability u Inherent Management Capabilities Cabling Hub Patch panel Cabling conducts Port status: - active - not active - partitioned Network Management - control - monitoring RJ-45 outlets May 1996 Ethernet Technology Rev. 1. 00 Page 11

10 BASE-T&F Design Rules 1 2 Link segments 1 10 BASE-T Max. 100 m. 3 3 4 10 BASE-F Max. 1000 m. 10 BASE-F Max. 500 m. 4 5 May 1996 Ethernet Technology Rev. 1. 00 Page 12 2

Ethernet Transparent Bridges u Bridges Receive and Buffer the Frames u Each Side of a Bridge is a Separate Collision Domain u Bridges Decide to Discard or Forward Packets u Bridges allow for a more Effective Utilization of the Overall Bandwidth Collision Domain Dedicated 10 Mbps Bridge Dedicated 10 Mbps Collision Domain May 1996 Ethernet Technology Rev. 1. 00 Page 13

Fast Ethernet 100 Mbps: î 100 BASE-T or î 100 VG-Any. LAN May 1996 Ethernet Technology Rev. 1. 00 Page 14

Switched Ethernet Full duplex 10 Mbps 100 BASE-T Replaces the ‘old’ Hub Ethernet Switch Shared 10 Mbps segment Existing cabling and adapters Dedicated 10 Mbps segments May 1996 Ethernet Technology Rev. 1. 00 Page 15

May 1996 Ethernet Technology Rev. 1. 00 Page 16