Direct answer
The VPN protocol commonly associated with using IPsec to provide data encryption is IPsec VPN—that is, a VPN built on the IPsec protocol suite.
Simple model: how IPsec VPN provides encryption
At a high level, an IPsec-based VPN protects data by applying IPsec security services to traffic between endpoints (for example, two gateways or a gateway and a device). Those security services include two key ideas:
- Encryption: data is encrypted so that intercepted traffic is not readable.
- Authentication/integrity: the system can verify that data was not altered in transit.
In practice, “IPsec VPN” is the umbrella term for VPN implementations where IPsec is the cryptographic and security mechanism.
Where confusion comes from (and what this answer does not claim)
People sometimes expect “the one VPN protocol” to be a single standard that always uses IPsec. In reality, VPNs can be built on different protocol approaches:
- Some VPNs use other tunneling and key-exchange mechanisms rather than IPsec.
- Some products may support multiple VPN types, so the protocol used for a particular tunnel can vary by configuration.
Because no specific vendor or configuration details are provided here, the only safe, non-changing conclusion is the definitional one: IPsec-based encryption corresponds to IPsec VPN, not a different VPN protocol name.
Practical checks you can do
To verify whether a given VPN uses IPsec for encryption, look for protocol wording such as “IPsec” or “IPsec VPN” in the tunnel/type settings. If the documentation describes the security mechanism in terms of IPsec (and not a different tunnel protocol), then the VPN is using IPsec to provide the encryption and related protections.
If you only see a general term like “VPN” without stating the tunnel/security protocol, you cannot conclude it uses IPsec—you would need the specific protocol details for that VPN mode.