Ericsson LMU Munich Dell EMC Encapsulating Security Payload (ESP) sends an initialization vector (IV) in each packet. The size of IV depends on the applied transform, being usually 8 or 16 octets for the transforms defined by the time this document is written. Some algorithms such as AES-GCM, AES-CCM and ChaCha20-Poly1305 when used with IPsec, take the IV to generate a nonce that is used as an input parameter for encrypting and decrypting. This IV must be unique but can be predictable. As a result, the value provided in the ESP Sequence Number (SN) can be used instead to generate the nonce. This avoids sending the IV itself, and saves in the case of AES-GCM, AES-CCM and ChaCha20-Poly1305 8 octets per packet. This document describes how to do this.