Route issue between two residential isps
I have been fighting for the last month between two residential ISPs and Hurricane Electric. I do offsite backups of my mom's PC in Miami to a NAS in north colorado. We have been having odd bandwidth issues. Any traffic from miami to colorado is being rate limited heavily. Any traffic from colorado to miami is going at closer line speed. The miami side is on bluestream fiber with 200/200 Mbps and the Colorado side isp is Allo Fiber with 1Gpbs.
iperf from colorado point of view
[ ID][Role] Interval Transfer Bitrate Retr
[ 5][RX-S] 0.00-10.06 sec 3.88 MBytes 3.23 Mbits/sec receiver
[ 8][TX-S] 0.00-10.06 sec 150 MBytes 125 Mbits/sec 5259 sender
iperf from miami point of view
[ ID][Role] Interval Transfer Bitrate Retr
[ 5][TX-C] 0.00-10.01 sec 4.00 MBytes 3.35 Mbits/sec sender
[ 5][TX-C] 0.00-10.06 sec 3.88 MBytes 3.23 Mbits/sec receiver
[ 7][RX-C] 0.00-10.01 sec 150 MBytes 126 Mbits/sec 5259 sender
[ 7][RX-C] 0.00-10.06 sec 146 MBytes 122 Mbits/sec receiver
Both ISPs have pointed at each other and I also had a ticket with Hurricane Electric who claimed the paths between the ISPs look to be clean.
If I connect the miami pc to a VPN provider like Nord, Proton or any of the major providers we can then get full speed again in both directions which makes me think it's not the local pc. The path taken when going over VPN is very different then when using the direct ISP routes.
I was wondering what this community would suggest doing for next steps to figure this out? I did some packet captures and there's a large amount of tcp retransmissts on the backup traffic which makes me think something between the isps is acting up.