Ipsec

Hello
Is ipsec implemented only between routers connected to each other through internet?
Can we use ipsec for the security of wireless point to point connections?

You can use IPsec to encrypt any kind of connection. The price to pay is the CPU load (if the CPU is weak, this translates into “bandwidth reduction”) and additional delay which also depends on the CPU throughput and whether encryption is supported in hardware by that CPU.

Thanks