IPsec protocol works in the third layer of OSI model, which makes it suitable for protecting TCP or UDP-based protocols when used alone (for example, Secure Sockets Layer (SSL) cannot protect the communication flow of UDP layer).
IPsec is located at the network layer. SSL is located at the transport layer. They are all included in the network security architecture.
Digital signature and authentication are two technologies, including negotiation layer and recording layer. PGP protocol is widely used on the Internet, especially in the protection of e-mail. It combines the chain encryption algorithm of RS and IDEA, and works in the application layer. TLS is very similar to SSL and is a subsequent version of SSL. IPSEC is a network layer VPN.
Ssl protocol encrypts the network connection between the transport layer and the application layer. SSL(SecureSocketsLayer) protocol and its successor, TLS(TransportLayerSecurity), are a security protocol that provides security and data integrity for network communication.