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Entry #461: How does the TLC protocol work?

How does the TLC protocol work?
The Sightline Power Agents contain a special process called a listener, which listen for connection requests on a particular port, similar to a web server. Sightline leverages a default TCP/IP port for this process, 1645, which can be modified if desired. Connection requests are made from either the EA/V or EDM products in order to download the performance data from the Power Agent. The application leverages a "callback" model, which means within the initial request, the EA/V or EDM product specify to the Power Agent a specific port for the data communication traffic. Once the initial handshake is complete, the Power Agent begins the data connection session back to the EA/V or EDM product via the port provided. By default, this is a random port provided by the operating system. The communication flow looks as follows:

EAV = Expert Advisor / Vision or EDM
PA = Power Agent

1. EAV [Random High Port] PA [1645]
2. PA [Random High Port] EAV[Callback Port]

In the example above, the connection shown in "1." is very short lived, terminating once step "2." is initiated. "2." Will stay open as long as the data connection is active within EA/V or EDM.