Huawei Technologies Huawei Technologies Network slicing can be used to meet the connectivity and performance requirement of different services or customers in a shared network. An IETF network slice may span multiple network domains. In the context of 5G, the 5G end-to-end network slices consist of three major types of network segments: Radio Access Network (RAN), Transport Network (TN) and Core Network (CN). In order to facilitate the mapping between network slices in different network segments and network domains, it is beneficial to carry the identifiers of the 5G end-to-end network slice, the multi- domain IETF network slice together with the intra-domain network slice identifier in the data packet. This document describes the framework of end-to-end IETF network slicing, and introduces the identifiers for 5G end-to-end network slice and the multi-domain IETF network slice in the data packet. The roles of the different identifiers in packet forwarding is also described. The network slice identifiers can be instantiated with different data planes.