TCP Multiplexing

TCP Multiplexing

TCP Multiplexing is loosely based on established connection pooling techniques utilized by application server platforms to optimize the execution of database queries from within applications. An ADC establishes a number of connections to the servers in its pool and keeps the connections open. When a request is received by the ADC from the client, the request is evaluated and then directed to a server over an existing connection. This has the effect of reducing the overhead imposed by establishing and tearing down the TCP connection with the server, improving the responsiveness of the application.

Some ADN implementations take this technique one step further and also multiplex HTTP and application requests. This has the benefit of executing requests in parallel, which enhances the performance of the application.

TCP Optimization

There are a number of RFCs which describe mechanisms for improving the performance of TCP. Many ADN implement these RFCs in order to provide enhanced delivery of applications through more efficient use of TCP.

The RFCs most commonly implemented are:

* Delayed Acknowledgements [4]
* Nagle Algorithm [5]
* Selective Acknowledgements[6][7]
* Explicit Congestion Notification ECN[8][9]
* Limited and Fast Retransmits[10][11]
* Adaptive Initial Congestion Windows[12]