A colored optical fiber including a glass optical fiber; a primary coating layer that covers the glass optical fiber; a secondary coating layer that covers the primary coating layer; and a colored layer that coats the secondary coating layer. In embodiments, a storage medium may have instructions to enable the computing device to monitor interactions with the first computing device by a user of the first computing device. Since the TCP’s advertised window size is not accepted as the absolute amount of buffer space available at the receiver, the sender is not constrained by the absolute value of the receiver’s advertised window size and instead can transmit more data than the absolute value of the advertised window, enabling the system to increase the actual window size without modifying the link ends.