VPN

Some info...

IPSec

MTU

MTU (The maximum transmission unit) is the size, in bytes, of the largest packet supported by a network layer protocol, including both headers and IP packet payload. Network packets sent over a VPN tunnel are encrypted and then encapsulated in an outer packet so that they can be routed - MTU considerations | Cloud VPN

Можно затраблшутить сетевые проблемы между локациями VPN увеличив MTU, например с 1400 до 1414.