Why is ESP recommended for certain applications?

ESP, or Encapsulating Security Payload, is designed to provide confidentiality, authenticity, and integrity for data being transmitted over an IP network. It is particularly well-suited for certain applications that utilize the User Datagram Protocol (UDP), such as Voice over IP (VoIP).

VoIP applications often require real-time data streaming, which is sensitive to delays and interruptions. Because UDP does not establish a connection before transmitting data, it is more efficient for time-sensitive applications. ESP complements this by ensuring that the data packets are encrypted and authenticated without adding significant overhead, which could introduce latency.

In contexts like VoIP, where maintaining quality of service is critical, ESP's ability to securely transmit data while preserving the lightweight nature of UDP makes it the recommended choice for ensuring both security and performance. This optimization for UDP ensures that the performance requirements of real-time applications can be met while also providing essential security features.