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Liaison statement

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State Posted
Submitted Date 2021-05-17
From Group GSMA-ZTC
From Contact David Pollington
To Group tsvwg
To Contacts Gorry Fairhurst <>
David Black <>
Wesley Eddy <>
Cc Zaheduzzaman Sarker <>
Martin Duke <>
Transport Area Working Group Discussion List <>
Wesley Eddy <>
Gorry Fairhurst <>
David Black <>
Response Contact David Pollington <>
Purpose For information
Attachments ZTC_LS_01%20-%20GSMA%20ZTC%20LS%20to%20IETF%20TSVWG
1. Background

The GSMA Zero Touch Connectivity (ZTC) taskforce is working on a number of
propositions with a strong focus on operator provided multi-connectivity
solutions for residential (Hybrid Access) and mobile customer usage based on
3GPP ATSSS, TS23.501 as well as alternative ‘ATSSS’ Overlay solutions
independent of the 5G Core.

The operators engaged in GSMA ZTC consider MP-TCP (RFC8684; RFC8803) to be very
beneficial based on the results from a number of ZTC trials. However, with the
increasing share of QUIC in the overall traffic mix, a solution based solely on
MP-TCP becomes a limiting factor and precludes delivery of a comprehensive
customer proposition.

For that reason, the GSMA ZTC taskforce has identified the multipath extension
of DCCP (MP-DCCP) as a suitable network protocol for addressing this shortfall.
MP-DCCP is an interesting candidate approach for the multipath transport of
latency sensitive services and/or services with no or little demand on reliable
delivery and also supports adjustable re-ordering.

The GSMA ZTC taskforce see MP-DCCP as an interesting solution to support
multipath delivery of most traffic types in both residential broadband and
cellular (3GPP) solutions. Available prototypes based on open source code from have already shown an ability to provide Steering,
Switching and Splitting.

Having formal support for MP-DCCP within IETF at the working group level would
facilitate adoption in other standards bodies and vendor solutions and ensure a
timely and satisfying solution for operator provided multi-connectivity

2. Request to IETF TSVWG
The GSMA ZTC taskforce kindly requests IETF TSVWG to adopt:
for standard track as a complement to MP-TCP to meet Operator needs for
multipath support. Along with this, GSMA ZTC would like to request that you
continue work on:

3. Contact
In the case of further questions and/or feedback to actions requested in the
present document these can be directed to David Pollington, GSMA ZTC taskforce
lead or Markus Amend, ZTC technical lead at DT [].