My question is quite simple. There is no explicit list of supported encryption modes. I was told the device apparently supports AES 128 ONLY, neither 192 nor 256 and so on. Is it true? Should I use this mode only to be sure hardware encryption will be enabled?
no, ALL IPsec modes will be accelerated.
Are you sure?
Your docs here (http://wiki.mikrotik.com/wiki/Manual:IP/IPsec#Hardware_encryption) are saying:
Hardware encryption allows to do faster encryption process by using built-in encryption engine inside CPU. > AES is the only algorithm that will be accelerated in hardware.
List of RouterBoards with enabled hardware support:
RB1000
RB1100AHx2
But it doesn’t say aes 128 only. I have them both models and they’ re working perfect with AES 256