This indicates the frame based modes of full duplex flow control for this port. The value is a sum. This sum initially takes the value zero. Then, for each mode, M, that the port supports, 2 raised to (M - 1) is added to the sum. For example, a port that supports Symmetric (M= 2), AsymmetricRX (M = 3) and AsymmetricTx (M = 4) would return a value of 14 ((2 ^ (2 - 1)) + (2 ^ (3 - 1)) + (2 ^ (4 - 1))). Speed values should be calculated as follows: M Mode Description 1 Other None of the following 2 Symmetric Receive and Transmit Pause Frames 3 AsymmetricRx Receive Pause Frames 4 AsymmetricTx Transmit Pause Frames