I've noticed that on most of my FTP transfers I'll see "TCP Zero Window" messages throughout the transfer. In the capture (I'm capturing on the LAN side of the client before optimization) they all come from the Server and not the client. Sometimes there are very few and sometimes there is a Zero Window every 10 or 20 packets.
From my understanding with a setup like this:
There are three conversations going on, one between the client and the local WAE, one between the two WAE's and one between the Server and it's local WAE.
My question is where are the "TCP Zero Window" messages coming from?? Are they coming from the WAE or are they coming from the server back to the client. I've had the systems guys adjust the buffer settings on the server but I'm still seeing them.