I captured packets after users complained pool performance between an AS 400 in our network and a vendor website in the Internet. AS 400 initialized Syn packet with window site of 65535 and kept it at 1048576 and the vendor website kept its window size at 6000-4000 range. I saw a lot of retransmission and user complained the slowness.
Our internet pipe is 45 m with 99% egress utilization and 36% igress. My question is that, does the constant window site of 1048576 impacted the performance and can it be scaled so that communications with limited bandwidth be improved.