The present document studies possible candidate protocols for the user plane in 5GC based on Rel-16 stage 2 requirements. This technical report covers the following analysis:

• List architectural requirements and key issues;
• Identify the possible candidate protocols for user-plane including GTP-U as existing protocol, specified for Rel-15;
• Define a list of evaluation criteria based on Rel-16 stage 2 architecture and procedures to evaluate the candidate protocols;
• Evaluate the candidate solutions against the list of requirements and the potential benefits against the existing user plane solution in 5GS.

The N3 and N6 user plane interfaces are out of the scope of this study. N3 uses GTP-U (see clause 4.3.1 of TS 38.300).