Ethernet




Variations of Ethernet:

Related, but not necessarily compatible



Physical Interconnection and Speed

Multiple Implementations of Ethernet:



Physical Interconnection and Speed

10Base5 ("Thick Ethernet")

10 Mbps, baseband, 500 m/segment



Physical Interconnection and Speed

Baseband

1Base5
1 Mbps, baseband, 500 m/segment
(AT&T StarLAN)



Physical Interconnection and Speed

10Base2 ("Cheapernet")

10 Mbps, baseband, 185 m/segment



Physical Interconnection and Speed

10Base-T ("Twisted Pair Ethernet")
10 Mbps, baseband, Unshielded Twisted Pair
100Base-T ("Fast Ethernet")
100 Mbps, baseband, Unshielded Twisted Pair
100Base-F

100 Mbps, baseband, Fiber Optic



Ethernet Implementation

10Base5

  • Backbone is yellow semi-rigid .4" diameter coax
  • Segment max 500 m
  • 100 stations/segment limit
  • Segments may be connected using repeaters (baseband)
RG-11



Ethernet Implementation

10Base5

  • Impedence 50 ohms
  • Must be terminated
  • Single earth ground
  • Must be insulated to prevent shock
  • Connect stations to backbone with a Medium Access Unit (MAU)
  • Transceiver
  • Station spacing must be a multiple of 2.5 m



Ethernet Implementation

10Base5

Cable from Backbone to station is called AUI cable (Attachment Unit Interface)

  • 4 - Pair drop cable
  • Maximum length is 50 m.
  • 4 - Pairs are for:
    • Send
    • Receive
    • Power to tranceiver
    • Collision detection



Ethernet Implementation

10base5

  
10base5 Diagram



Ethernet Implementation

10Base5

Fan-out box

  • Eases Installation
  • Solves 100 station per segment limit



Ethernet Implementation

10Base2

  • RG58/U Coax cable
  • 50 ohm termination
  • Coax is run to the back of every station
  • Splice out of coax with BNC "T" connector

10base2 diagram



Ethernet Implementation

10Base2

  • Maximum length per segment is 185 m.
  • Adapters (transceivers) are available to convert:
    • 10Base5 to/from 10Base2
    • 10Base2 to/from 10Base-T
    • 10Base-T to/from 10Base5



Ethernet Implementation

10Base-T

  • 24 gauge Unshielded Twisted Pair (UTP)
  • Connector is RJ-45 Phone Jack
  • Wired in a star topology
  • All stations connect to a hub/concentrator
UTP RJ-45
UTP UTP with RJ-45 Connector
10base-T Picture



Other Implementations:

Early Implementations:

  • AT&T: StarLan10 (1Base5)
  • Synoptics: LattisNet



Other Implementations:

  • Broadband Ethernet 5 Mbps
    • Designed to fit in a TV channel

  • Fiber Ethernet
    • Switching done optically in hub



Access Control:

CSMA/CD:
Carrier Sense, Multiple Access with Collision Detection

  

Access Control, Variation:

CSMA/CA:
Carrier Sense, Multiple Access with Collision Avoidance

  • Implemented in Apple LocalTalk Link Access Protocol (LLAP)


Local Area Networks - Token Ring




Standards For Manufacturers:

Chip Sets Manufacturers:



Physical Interconnection and Speed

Typical Speeds:



Physical Interconnection and Speed

Wire Types:

Connectors:

IBM Type 1 
connectorRJ-45 connector
STP with IBM Type 1 ConnectorUTP with RJ-45 Connector



Token Ring Architecture

  



Token Ring Architecture



Active Monitor:

  • First one on ring
  • Watches for presence of good Token
    (Special 3 bytes)
  • Listens for reports of errors
  • Replaces a trashed token
  • Manages Ring Recovery



Access Control:


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