The author states: >"Many network operators use the IP and transport packet headers to perform traffic engineering functions, packet interception and forced pr

The author states: >"Many network operators use the IP and transport packet headers to perform traffic engineering functions, packet interception and forced proxy caching." I'm guessing this referring to transparent hardware caches looking at Layer 7/HTTP headers? And then: "Various forms of middleware may reach into the TCP control fields and manipulate these values to modify session flow rates" Does the author mean TCP flow control here? So there exists middleware which changes the ACK and RWND values in TCP headers? Does anyone know what middleware vendors do this? I'm guessing this might be done as as part of network "accelerator" hardware devices like Riverbed. Is this correct?