Renaissance of TCP's

Will we one day reach a point where TCP algorithms are so varied and specific that TCP streams could flexibly adapt to connection-specific conditions and applications could decide what kind of TCP protocol they want and when? After learning in class about the variety of modifications and additions proposed to TCP over the past decade, it almost seems natural to evolve TCP in that direction.

For instance, certain algorithms like SCTP or HSTCP were designed to handle a specific scenario like efficient bandwidth utilization on long fat links, but were shown to perform unfairly in more standard usage scenarios. In a more dynamic TCP environment, a TCP implementation could adapt itself to measured conditions like high RTT and low congestion and switch congestion avoidance algorithms entirely and completely transparently to the client application.

Another use case of dynamic TCP could be application-driven TCP. As an example, authors in one paper we read claimed that the current implementation of TCP is not optimized for P2P applications. We also read of another algorithm specifically designed for the data center. If an application was allowed to select per-stream protocols, they could then choose the algorithm that best suites the needs of the application itself and the data it is sending. As a further possibility, an application, when installed, could install a new version of TCP that it prefers in some or all scenarios.

This flexibility and ubiquity of TCP opens up many issues related to fairness, correctness of implementation, efficiency of dynamic algorithms that generate metrics an application can respond to, and so on, but they also open up the possibility for a much more flexible transport layer that could adapt to the needs of individual connections or applications, which may help improve overall connection efficiency on the Internet.