Nokia NTT Futurewei Telefonica Juniper Networks This document provides a definition of the term "IETF Network Slice" for use within the IETF and specifically as a reference for other IETF documents that describe or use aspects of network slices. The document also describes the characteristics of an IETF network slice, related terms and their meanings, and explains how IETF network slices can be used in combination with end-to-end network slices or independent of them.