The network utilized is not one of the key components of an encryption system architecture. In fact, a network is not even required for encryption systems or the processing and protection of data. The data, software used for the encryption engine itself, and the keys used to implement the encryption are all core components of an encryption system architecture.

With IaaS, you rent raw servers and networks and can install any OS and applications you want.
In PaaS, the provider manages the OS layer. SaaS customers only use the application. FaaS is even more abstract.

A cross-site request forgery (CSRF) attack forces a client that a user has used to authenticate to an application to send forged requests under the user's own credentials to execute commands and requests that the application thinks are coming from a trusted client and user. Although this type of attack cannot be used to steal data directly because the attacker has no way of seeing the results of the commands, it does open other ways to compromise an application. Missing function-level access control exists where an application only checks for authorization during the initial login process and does not further validate with each function call.
Cross-site scripting occurs when an attacker is able to send untrusted data to a user's browser without going through validation processes. An injection attack is where a malicious actor sends commands or other arbitrary data through input and data fields with the intent of having the application or system execute the code as part of its normal processing and queries.

Explanation
Because IPsec is implemented at the system or network level, it is the responsibility of the systems staff. IPsec removes the responsibility from developers, whereas other technologies such as TLS would be implemented by developers.