The port is able to perform DMA transmit. Ports that do not have this bit set will only be able to transmit at a limited rate.
The port will hard slice packets when they exceed the maximum frame size.
The port can calculate the IPv4 checksum on transmit.
The port can calculate the UDP checksum on transmit.
The port can calculate the TCP checksum on transmit.
The port can inject a time stamp when transmitting packets.
The port can transmit timed using the time stamps in each packet.
The port has bypass functionality.
The port can be disabled.
The port has 64-bit time stamp support.
The port can only be used to receive data. No transmit capabilities.
The port can replicate the TX traffic of another port.