Basic Goals of Data Link Protocols

• Negotiation of parameters for higher layer protocols

• Framing of higher layer data

• • I.e., IP packet inside an Ethernet frame

• Medium access

• • When to transmit and/or receive packets

• Link establishment and testing

• • Determine connectivity and data rate
  • Handshakes and probes

• Error control

• • Detect bit errors and/or lost packets

• Flow control

• • Prevents a host from transmitting too rapidly