Computer Networks

Networking

• LAN (Ethernet)

  • Media Access Control (MAC) Addresses [in header]

  • Carrier Sense Multiple Access (CSMA)

  • Collision

    • When packets are sent at the same time

    • Solved by short, random delay (1 sec + random short extra delay)

      • If continuous collisions, increase by 2x delay each time (exponential backoff)

  • Collision domains

    • Divides the network into smaller sets; uses a switch as mediator between networks

Routing

• Circuit Switching

  • Literally switching circuits to route traffic

• Message Switching

  • Multiple routes → fault tolerant

  • Hop count → helps identify issues with routing (when hop count > hop limit)

• Packet Switching

• Internet Protocol (IP)

• Splits large transfers into packets

OSI Model

Encapsulation - The process of wrapping data with the appropriate headers necessary for transfer and routing.