Final answer:
The 2nd step in the site-to-site IPSec encryption process is Encapsulation, which involves securely wrapping data packets with IPSec headers for protected transmission across an IP network.
Step-by-step explanation:
The 2nd step of the site-to-site IPSec encryption process is Encapsulation. After the initial Internet Key Exchange (IKE) phase, where two IPSec peers establish a secure, authenticated channel and negotiate encryption and authentication methods, encapsulation takes place. This involves wrapping data packets within new packets that provide the necessary IPSec headers and trailers. Each data packet is wrapped with an IPSec header that contains information required to decrypt the packet at the other end of the tunnel. This process of 'encapsulating' the data ensures secure transmission across an IP network by creating a virtual tunnel between the two sites.