LTM order of operation

it depends on what profiles you have applied to the virtual. For example, with a fastL4 profile on a tcp connection, the handshake to the server will occur as soon as the handshake with the client has completed, whereas with a tcp profile, the handshake is not completed to the server until the first request is made on a successful tcp connection. That is, of course, unless oneconnect is enabled, and the bigip has established the tcp session...

There are many considerations for the process.