AFDX Communication ports are used by avionic subsystems to send messages to each other. Two services are provided by MX Foundation for these ports; Acquisition and Sampling. Acquisition is used for queuing ports which contain a buffer that will hold a limited number of messages. Once read, the messages are removed from the buffer. Sampling is used for ports that only hold a single message. The message can be read multiple times without deletion. Freshness counters are used to know if the message is still valid. With COM Port, only the payload is returned, the headers (MAC, IP, UDP) are removed.

The KMXF_A664_ES_MODE attribute defines if the ports are redundant or independent. When redundant, only the first port (port A) is used to configure both ports (for example, setting the speed on port A will also set the same speed on port B).