How is the Internet a feedback system?
Q: How is the Internet a feedback system?
A: The Internet we use today has a hierarchical structure that most applications are built on top of layered protocol stacks. The applications include e-mails, file transfers, remote log in, web browsing and etc. The simplified five layers include the application layer, transport layer, network layer, link layer and physical layer. Feedback theory is widely used by those protocols to achieve certain performance. For example, congestion control protocols (in the network layer) aim to provide efficient and fair utilization of the network bandwidth. In the Internet most 1-to-1 communication sessions' congestion control use Transmission Control Protocol (TCP) . TCP limits the amount of transmitted but not yet acknowledged data and it consists of two major components: 1. A feedback component notifies a transmitting entity about the current status of congestion of the network. 2. Based on this feedback information, an adjustment algorithm (for example, additive increase and multiplicative decrease) regulates the transmission.
For a detailed description of how TCP works, please see  below.
--Ling Shi 11:37am, 3 Oct 2006 (PDT)
(Sorry for the late response, but I got the problem just now due to the busy schedule of another TA who was supposed to answered the problem yesterday).