The link layer involves communication channels that connect nodes along communicaiton paths, links!

Layer-2 packets are frames and they encapsulate datagrams

Link layer protocols include

  • WiFi
  • Ethernet
  • framing encapsulates a datagram into a frame, adding a header and trailer, channel access on shared mediums
    • The header contains a MAC address
  • reliabile delivery between adjacent nodes
  • flow control
  • error detection
    • retransmission/dropping
  • error correction
  • half-duplex and full-duplex links