Huawei Technologies Huawei Technologies China Unicom China Telecom 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 be used for 5G or other network scenarios. In the context of 5G, the 5G end-to-end network slices consist of three major types of network technology domains: Radio Access Network (RAN), Transport Network (TN) and Core Network (CN). The transport network slice can be realized as IETF network slices. In the transport network, the IETF network slice may span multiple network administrative domains. In order to facilitate the mapping between network slices in different network technology domains and administrative domains, it is beneficial to carry the identifiers related to the 5G end-to-end network slice, the multi-domain IETF network slice together with the intra-domain network slice related identifier in the data packet. This document describes the framework of end-to-end IETF network slicing, and introduces the identifiers related to 5G end-to-end network slice and the multi-domain IETF network slice. These identifiers can be carried in the data packet. The roles of the different identifiers in packet forwarding is also described. The network slice identifiers may be instantiated with different data planes.