Why sender did not have more in-flight bytes to client?
Hi
I use Bluecoat proxy for testing, and the configured proxy server has a 500Kbytes TCP window size. But I found the proxy sometimes just sent two packages to the client, then the client will send one ack.
Sometimes, the proxy will send 15 packages (21456 bytes in flight) to the client and then receive the client's ACK back.
Does anyone know how the proxy (sender) controls the in-flight bytes? is it possible to have more in-flight bytes to increase the throughput?
the client is windows 10 and connecting to server via bluecoat proxy. And the client and sender (bluecoat) are on LAN and RTT is less than 1 ms.
Thank you!
Have you looked at the window size in the client ACKs?
There may be several reasons why the TCP window size is not fully utilized. For example:
Maybe using a (software) WAN emulator may help to get more realistic behaviour.
for download (server -> bluecoat -> client). I captured in client system, the ACK to bluecoat largest Calculated window size is 1723648 to bluecoat. I found from bluecoat to client the in-flight bytes can up to ~200KB, but most in-flight is between 50KB - 20 KB from Bluecoat to client.