Very slow file copy over IPsec tunnel in one direction

RouterOS General
1

Hello,
I have ipsec tunnel between CCR1009 (WAN 100Mbit) and RB751 (WAN 20Mbit)
File copy over tunnel from RB751 side is normal (1.8 megabytes/s)
But file copy over tunnel to RB751 side is only ~150 kilobytes/sec
Why so slow?

2

Why asking this? It has been explained so many times already…

3

Where?