Liaison statement
CP-173160: New Study Item on User Plane Protocol in 5GC

1. Overall Description:
3GPP working group of CT4 (Core and Terminal) would like to inform the IETF
that CT4 has initiated a study item on user plane protocol in 5GC for
Release-16 of 5G phase 2 (see CP-173160).

Based on the outcome from the IETF / 3GPP Coordination meeting at IETF#100,
3GPP CT4 got aware that IETF DMM WG is currently working on a possible
candidate protocol for the 3GPP 5G user plane protocol.

3GPP CT4 wants to emphasize that currently there is no related evaluation
ongoing in 3GPP. Nevertheless, a study item was approved for such a study to
start in the second half of 2018. The study will evaluate between existing
solutions within 3GPP and other protocols, based on the Release 16 stage 2
(system architecture) requirements.

3GPP CT4 would like to point IETF DMM to the following specifications on GTP-U.
The Release 16 stage 2 requirements are not yet known but it is worth looking
at latest GTP-U spec which will be evaluated through the study as the existing
protocol.

•       [1] 3GPP TS 29.281 (V15.1.0): GPRS Tunnelling Protocol User Plane
(GTPv1-U)

Following technical report provides information of how 3GPP considered GTP-U
apply to user plane of 5G_ph1:

•       [2] 3GPP TR 29.891 (V15.0.0): 5G System – Phase 1; CT4 Aspects

Furthermore, 3GPP would like to give the following general guidance to IETF
DMM, regarding user plane transport within 3GPP networks. These are technical
specifications that include also the necessary information to understand which
architectural, QoS, security-related and high-level requirements GTP-U
currently complies to within 5G_ph1.

•       [3] 3GPP TS 23.501 (V15.0.0): System Architecture for the 5G System
•       [4] 3GPP TS 23.502 (V15.0.0): Procedures for the 5G System
•       [5] 3GPP TS 23.503 (V15.0.0): Policy and Charging Framework for the 5G
System •       [6] 3GPP TS 33.501 (V0.6.0): Security Architecture (work in
progress)

2. Actions:
To IETF DMM:
ACTION:         CT4 respectfully asks IETF DMM to provide any information that
may be relevant to the above CT4 work by July 2018.

3. Date of Next CT and CT4 Meetings:
CT4#83  26th Feb – 2nd Mar 2018 Montreal, CAN
CT#79   19th – 20th Mar 2018    Chennai, India
CT4#84  16th – 20th April 2018  Kunming, China
CT4#85  21st – 25th May 2018    Osaka, Japan
CT#80   11th – 12th June 2018   La Jolla, USA
CT4#85-bis        9th –13th July 2018   TBD, France
CT4#86  20st – 24th Aug 2018    TBD, USA