Other Ethernet technologies Light Source

Other Ethernet Physical Layer Standards  100Base-X 100 Mbps 100Base-TX uses Cat 5 UTP to desktop  1000Base-X Gigabit Ethernet  Traditional Ethernet (before 10Base-T) 10Base5 10Base2

10Base5  Original Ethernet with slight changes  Thick coaxial cables  No hubs  Drop cables from stations to trunk cable  500 Meters maximum per segment  Maximum 5 segments between farthest stations  So maximum distance is 2500 meters Trunk Cable Segment Drop Cable

10Base5 15-pin DIX Connector AUI Drop Cable (Attachment Unit Interface) 50 meters maximum distance 10Base5 Trunk Cable 500 meters maximum distance Transceiver (Medium Attachment Unit or MAU)

10Base5 Segments  Runs of trunk cable 500 meters per segment (the 5 in 10Base5)  Repeaters Connect trunk cable segments Up to 5 segments between farthest two stations 2500 meters maximum distance

Coax (Coaxial Cable)  Signal is trapped between the two conductors Signals travel far Interference from outside signals is low  Problem: Being squeezed out of the market Cheaper UTP can now go almost as fast Optical fiber is faster, only slightly more expensive

Coax (Coaxial Cable)  Widely used in Cable television service To connect VCRs to televisions  Two conductors Inner wire Outer cylinder Inner Wire Outer Cylinder

Co-Axial Cable Insulation Outer Conductor (cylinder) Insulation Inner Conductor (wire)

Linking 10Base-T Hubs with 10Base5 10Base5 Segment 500 meters maximum Hub 10Base5 AUI Connector

Ethernet Hub with 10Base-T and 10Base5 Ports

10Base2  Uses less expensive thin coaxial cable (Cheapernet or Thinnet)  Segment can connect up to 30 stations  185 Meters/segment (the 2 in 10Base2)  With repeaters, 5 segments maximum between distant stations Segment with 3 PCs Daisy Chain Layout

10Base2  NIC has BNC Connector  T-Connector attaches to NIC BNC connector  Cable segments attach to tops of T  Don’t forget terminator NIC T-Connector BNC Connector Segment to Next PC

10Base2 Connection NIC Thin Ethernet (10Base2) Coaxial Cable 185m Maximum Per Segment 30 Stations Per Segment Maximum BNC T-Connector BNC T-Connector

Linking Hubs with 10Base2 10Base2 Segment 185 meters maximum Hub 10Base2 BNC Connector

Optical Fiber  Very thin glass Core is where signal travels Cladding is ring of glass around core Core and cladding have different indices of refraction Light Source Cladding Core

Single Mode Optical Fiber  Core and cladding are very thin All parts of a bit’s wavefront travel the same distance Arrive with little distortion Can propagate long distances Used in telephone company long-distance links Too expensive, difficult to install for LAN use Wavefront Light Source Core Cladding

Multimode Optical Fiber  Thick (usually around 62.5 micron core): easy to join  Different parts of wavefront travel different paths: limits distance before successive wavefronts overlap  Multimode is most common type in LANs  Step Index: core index of refraction is constant across core Light Source Cladding Core

Multimode Optical Fiber  Graded Index Index of refraction varies along core Rays at different angles travel similar distances Signals travel longer distances before distortion is bad Multimode graded index fiber is dominant today

10Base-F  Standard for connecting hubs  Can carry signals for 2,000 meters (2Km =~ 1.2 miles)  much farther and faster than 10Base5

Stackable Hubs  Physically Stacked  Can mix hubs of various types  Easy to add capacity  High-speed backplane or 10Base2 connectors link the stacked hubs (switch next class meeting) Visit 3Com for a view of actual products.3Com

Chassis Hubs  Chassis provides slots for expansion boards  Expansion boards are hubs of different types  Very high-speed backplane bus to link hubs