Consider now what happens when the user pauses the video during the
streaming process. During the pause period, bits are not removed from the client
application buffer, even though bits continue to enter the buffer from the server. If
the client application buffer is finite, it may eventually become full, which will
cause “back pressure” all the way back to the server. Specifically, once the client
application buffer becomes full, bytes can no longer be removed from the
client TCP receive buffer, so it too becomes full. Once the client receive TCP buffer
becomes full, bytes can no longer be removed from the client TCP send buffer, so
it also becomes full. Once the TCP send buffer becomes full, the server cannot send
any more bytes into the socket. Thus, if the user pauses the video, the server may
be forced to stop transmitting, in which case the server will be blocked until the
user resumes the video