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====== CCNA - Ethernet ======

===== TL;DR =====
Ethernet is the standard technology used for wired local area networks.
It defines how devices connect and communicate over copper or fiber.

===== Key takeaways =====
  * Ethernet is the base of most LANs
  * It uses frames, not packets
  * MAC addresses are used at Layer 2
  * Switches forward Ethernet frames
  * It can run over copper or fiber
  * Ethernet is cheap, simple, and widely used

===== Standards =====
Ethernet standards define speed, cable type, and transmission method.
Common examples:
  * 100BASE-TX
  * 1GBASE-T
  * 10GBASE-SR
  * 10GBASE-LR

===== Copper vs Fiber =====
**Copper**
  * cheaper
  * common for short distances
  * can carry [[poe|PoE]]

**Fiber**
  * longer distances
  * immune to EMI
  * more expensive

===== Useful concepts =====
  * Frame = Ethernet data unit
  * MAC address = Layer 2 identifier
  * MTU = maximum frame payload size
  * Duplex = send/receive behavior

===== Useful links =====
  * [[ccna:poe|PoE]]
  * [[ccna:switch-router|Switch & Router]]
  * [[ccna:osi-tcpip|OSI - TCP/IP]]