Ethernet Basics

Ethernet Basics

1. Frames

   • Prevent monopoly
   • Easier to transmit lost data
   • Preamble || Recip. MAC || Sender MAC || Type || DATA || Pad || FCS
     • Type - IPv4/6
     • Pad - makes up to 64 bytes if lower
     • FCS - CRC

2. CSMA/CD

   • Carrier Sense Multiple Access/ Collision Detection
     • CS
       • Checks to see if line free
     • MA
       • All nodes equal
     • If collision both nodes generate random then resubmit
     • 10% normal
     • Divide into collision domains

3. 10BaseT

   • 10Mbps
   • Basband
   • Twisted
   • 1,2 send 3,6 receive
     • TIA/EIA 568A/B Standards
   • Star bus

4. 10BaseFL

   • Fiber-optic
     • MMF
       • ST/SC
   • Star bus

5. Media Converter

6. Connecting Hubs

   • Uplink ports
     • Connect to normal
       • Daisy Chain
     • MDI-X
   • Crossover cables

7. Bridges

   • Connect 2 segments
     • Filters and forwards
   • Layer 2
     • based on MAC

8. Switches

   • Point to point connections
     • each port a CD
     • whole network called broadcast domain
   • uses MAC address
     • Creates SAT
   • Layer 2
   • Spanning Tree Protocol
     • BPDU
       • eliminates loops
       • talks to other switches
     • Bridge Loop/Switching Loop
       • redundant connections