Dynamic aggregation is implemented through the IEEE 802.3ad Link Aggregation Control Protocol (LACP).

LACP uses LACPDUs to exchange aggregation information between LACP-enabled devices. Each member port in a dynamic aggregation group can exchange information with its peer. When a member port receives an LACPDU, it compares the received information with information received on the other member ports. In this way, the two systems agree on which ports are placed in Selected state.

The LACPDU fields convey data for the LACP functions, including:
  • System LACP priority

  • System MAC address

  • Port priority

  • Port number

  • Operational key