Liaison statement
LS on 3GPP CT WG4 feedback on QUIC network level troubleshooting capabilities

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State Posted
Submitted Date 2019-10-14
From Group 3GPP-TSGCT-CT4
From Contact Susanna Kooistra
To Group quic
To Contacts Lars Eggert <lars@eggert.org>
Mark Nottingham <mnot@mnot.net>
Cc Mirja Kühlewind <ietf@kuehlewind.net>
QUIC Discussion List <quic@ietf.org>
Lars Eggert <lars@eggert.org>
Magnus Westerlund <magnus.westerlund@ericsson.com>
Mark Nottingham <mnot@mnot.net>
Response Contact georg.mayer.huawei@gmx.com
3GPPLiaison@etsi.org
Purpose For action
Deadline 2020-02-14 Action Taken
Attachments Liaison Statement on QUIC network level troubleshooting capabilities
Liaisons referring to this one Response to questions about QUIC network level troubleshooting capabilities
Body 
1. Overall Description:
3GPP CT WG4 is performing a feasibility study on the potential usage of QUIC
protocol for the 3GPP 5G Core Network in 3GPP°TR°29.893 (last version available
via the following link:
https://www.3gpp.org/ftp/Specs/archive/29_series/29.893/29893-120.zip). 3GPP CT
WG4 is currently waiting for the release of the first official version of QUIC
RFC in order to resume and conclude this study.

3GPP CT4 WG hence reviewed the IETF draft-ietf-quic-transport-19 and would like
to provide the following feedback on network level troubleshooting capabilities
of QUIC as compared to TCP (cf. clause°9.6.3 of 3GPP TR°29.893 for more
details):

-       QUIC replaces both TLS and TCP. One of the main differences indeed is
that QUIC encrypts the transport headers in addition to the payload, which is
highly relevant for the network level troubleshooting matters. The existing
Network OAM (Operation And Maintenance) solutions which are designed to make
use and act on TCP headers would hence not be able to troubleshoot QUIC traffic
and even less be easily adaptable to perform this task. -       QUIC includes
an optional measurement bit, named spinbit, which allows in-path probes to
measure both the round trip delay and the decomposition of the delay on both
sides of symmetrical path. -       As of version 19, QUIC specifications do not
support packet loss measurements. -       To enable an in depth analysis of the
performance (e.g. flow control, etc.) between a consumer 3GPP 5G core Network
Function (NF) and a producer NF, the decryption of the entire QUIC message is
often required in order to read the transport parameters of the QUIC packet
header. Contrary to HTTP/2 over TLS, this has the side effect of decrypting and
revealing application layer information to network probes.

2. Actions:
To IETF QUIC group
ACTION:         3GPP CT WG4 kindly asks IETF QUIC WG to take the above feedback
into consideration in QUIC version 1 specification and provide a feedback
(especially on the highlighted points).

3. Date of Next CT4 Meetings:
3GPP TSG CT4#95 11th – 15th November 2019       Reno, US
3GPP TSG CT4#96 24th – 28th February 2020       Sophia Antipolis, FR