SSTP: The problem with TCP over TCP, Part 1
TCP over TCP: Issues and Concerns<br>The Transmission Control Protocol (TCP) is undoubtedly a fundamental component in all modern day networks. The difficultly with TCP, however, begins when operating a TCP tunnel within TCP itself, which is often the cas
What all of these users share in common is the problem a TCP-based tunnel has when running within an existing TCP connection. TCP was originally designed with congestion controls that help mitigate issues with slow, latent and unreliable networks. When TCP was first designed, consumers did not have ultra-fast Internet connectivity. In fact, most consumers did not have Internet connectivity at all. If they did, it was a dial-up connection ranging from 300 to 1200 bits per second (bps) over unreliable copper telephone wire. Even universities and corporations had relatively slow and unreliable connections when compared to today’s standards. As a result, protocols like TCP were designed to accommodate this by using various congestion controls that would help to achieve high network performance while avoiding congestion collapse. These mechanisms contain timers, sent data acknowledgments and controls for the rate of data entering the network. Today’s modern TCP protocol implementations use the following four algorithms to maintain high performance: congestion avoidance, fast recovery, fast retransmit and slow-start.