Liaison statement
LS on work progress on Quantum Key Distribution (QKD) network in SG13 (as of November 2022)

ITU-T SG13 Queston 16/13 is pleased to inform you of our progress on Quantum
Key Distribution (QKD) topics.

As we informed you, SG13 has published 13 Recommendations and 1 supplement on
QKDN as follows: - Recommendation ITU-T Y.3800 “Overview on networks supporting
quantum key distribution”; - Recommendation ITU-T Y.3801 “Functional
requirements for quantum key distribution networks”; - Recommendation ITU-T
Y.3802 “Quantum key distribution networks – Functional architecture”; -
Recommendation ITU-T Y.3803 “Quantum key distribution networks – Key
management”; - Recommendation ITU-T Y.3804 “Quantum key distribution networks -
Control and management”; - Recommendation ITU-T Y.3805 “Quantum Key
Distribution Networks - Software Defined Networking Control”; - Recommendation
ITU-T Y.3806 “Quantum key distribution networks - Requirements for quality of
service assurance”; - Recommendation ITU-T Y.3807 “Quantum Key Distribution
networks - QoS parameters”; - Recommendation ITU-T Y.3808 “Framework for
integration of quantum key distribution network and secure storage network”; -
Recommendation ITU-T Y.3809 “A role-based model in quantum key distribution
networks deployment”; - Recommendation ITU-T Y.3810 “Quantum key distribution
network interworking - Framework”; - Recommendation ITU-T Y.3811 “Quantum key
distribution networks - Functional architecture for quality of service
assurance”; - Recommendation ITU-T Y.3812 “Quantum key distribution networks -
Requirements for machine learning based quality of service assurance”; -
Supplement ITU-T Y.Sup70 “Quantum Key Distribution Networks - Applications of
Machine Learning”.

Since July 2022 three more Recommendations were approved and in the Q16/13
Rapporteur Group Meeting (Geneva, 14 – 25 November 2022), Q16/13 has made
progress of the work items as reported below.

1. The items approved after the July 2022 SG13 meeting

The draft Recommendations ITU-T Y.3810, Y.3811, Y.3812 were approved.

Draft Recommendation ITU-T Y.3810 (ex Y.QKDN_iwfr) “Quantum key distribution
network interworking - framework”

For quantum key distribution networks (QKDN), Recommendation ITU-T Y.QKDN-iwfr
specifies framework of QKDN interworking (QKDNi). This Recommendation describes
the overview of interworking QKDNs, the reference models, and the functional
models of gateway functions (GWFs) and interworking functions (IWFs). The
configurations for QKDNi are specified. Appendix I includes QKDNi with
different key relay schemes.

Draft Recommendation ITU-T Y.3811 (ex Y.QKDN-qos-fa) “Quantum key distribution
networks - Functional architecture for quality of service assurance”

This Recommendation specifies a functional architecture of QoS assurance for
the quantum key distribution networks (QKDN).

This recommendation first provides an overview of the functional architecture
of QoS assurance for the QKDN. It then describes the functional architecture of
QoS assurance which includes functional entities such as QoS data collection,
data processing, data storage, data analytics, QoS anomaly detection and
prediction, QoS policy decision making, and enforcement and reporting. Based on
the functional entities described in the functional architecture, this
Recommendation specifies a basic operational procedure of QoS assurance for the
QKDN.

Draft Recommendation ITU-T Y.3812 (ex Y.QKDN-qos-ml-req) “Quantum key
distribution networks - Requirements for machine learning based quality of
service assurance”

This recommendation specifies high-level and functional requirements of machine
learning (ML) based QoS assurance for the quantum key distribution networks
(QKDN).

This recommendation first provides an overview of requirements of ML based QoS
assurance for the QKDN. It describes a functional model of ML based QoS
assurance and followed by associated high level and functional requirements of
ML based QoS assurance.  And some use cases are described.

2. The items consented after the July 2022 SG13 meeting

The following Recommendations were consented.

Draft Recommendation ITU-T Y.3813 (ex Y.QKDN-iwrq) “Quantum key distribution
networks interworking – functional requirements” in TD144-WP3

For quantum key distribution networks (QKDN), Recommendation ITU-T Y.QKDN_iwrq
specifies functional requirements for QKDN interworking (QKDNi). This
Recommendation describes the functional requirements for key management layer,
QKDN control layer, and QKDN management layer, for interworking using gateway
nodes (GWNs) and/or interworking nodes (IWNs).

Draft Recommendation ITU-T Y.3814 (ex Y.QKDN-ml-fra) “Quantum key distribution
networks - functional requirements and architecture for machine learning
enablement” in TD145-WP3

QKDN is expected to maintain stable operations and meet the requirements of
various cryptographic applications efficiently. Due to the advantages of
machine learning (ML) related to autonomous learning, ML can help to overcome
the challenges of QKDN in terms of quantum layer performances, key management
layer performances and QKDN control and management efficiency. Based on the
functional requirements and architecture of QKDN in [ITU-T Y.3801] and [ITU-T
Y.3802], this recommendation is to specify one possible set of functional
requirements and a possible architecture for ML-enabled QKDN (QKDNml),
including the overview, the functional requirements, architecture and
operational procedures of QKDNml.

3. Revised on-going work items

Draft Recommendation ITU-T Y.QKDN-iwac “Quantum key distribution network
interworking - architecture” in TD146-WP3

For quantum key distribution networks (QKDN), Recommendation ITU-T Y.QKDN_iwac
specifies functional architecture for QKDNi.

Draft Recommendation ITU-T Y.QKDN-rsfr “Framework of quantum key distribution
network resilience” in TD147-WP3

For quantum key distribution network (QKDN), this recommendation describes a
framework of QKDN resilience. This recommendation describes the overview of
QKDN resilience, models and requirements of QKDN protection and recovery. It
also includes different use cases of QKDN resilience in the appendix.

Draft Technical Report ITU-T TR-QEFN “ITU-T’s views for Quantum-Enabled Future
Networks” in TD148-WP3 The scope of this Technical Report is to describing
ITU-T’s Views for Quantum-Enabled Future Networks (QEFN) for the future
networks study to act as a document to help SG13 to study the future network
evolution towards Quantum era.

Draft Recommendation ITU-T Y.QKDNi_SDNC “Quantum Key Distribution Network
Interworking – Software Defined Networking Control” in TD149-WP3

This draft Recommendation specifies the Software Defined Network control for
the interworking including the overview of the role of SDN control for the
interworking between QKDN providers, the functional entities of SDN control for
the interworking, the interfaces of SDN control for the interworking, the
functional requirements of SDN control for the interworking, and the security
considerations.

Draft Recommendation ITU-T Y.QKDNf_fr “Framework of Quantum Key Distribution
Network Federation” in TD150-WP3

This draft Recommendation specifies the framework of Quantum Key Distribution
Network Federation (QKDNf) including the overview of QKDNf, reference
architecture for enabling QKDNf, functional entities of QKDNf, reference points
for the QKDNf, functional requirements of the QKDNf, overall operational
procedures of QKDNf and security considerations.

Draft Supplement ITU-T Y.supp.QKDN-roadmap “Standardization roadmap on Quantum
Key Distribution Networks” in TD151-WP3

Supplement Y.supp.QKDN-roadmap to ITU-T Y-series Recommendations provides the
standardization roadmap on quantum key distribution networks. It describes the
landscape with related technical areas of trust technologies from an ITU-T
perspective and list up related standards and publications developed in
standards development organizations (SDOs).

4. New work items agreed at the November 2022 Working Party 3/13 meeting

Draft Technical Report ITU-T TR-QN-UC “Use cases of quantum networks beyond
QKDN” in TD158-WP3 This Technical Report presents the use cases of quantum
networks beyond QKDN under three categories as follows:

- Use cases based on quantum information networks (QINs):  use cases that
depend on QIN to realize their function as for example, but not exclusive, to
distributed quantum computing, distributed quantum sensing, quantum clock
network, etc. - Use cases beneficial for classic networks: use cases that can
provide additional functionality, new characteristics, or improved performance
for classic ICT networks as for example, but not exclusive to, quantum random
number generator (QRNG), quantum time synchronization (QTS), quantum
cryptography beyond QKD, etc. - Use cases where the network plays an intrinsic
role for the QIT application:  use cases in which the QIT application is
significantly defined or enhanced by the functionality provided by a QIN and/or
a classical network and is beyond simple remote access of a QIT application via
a classical network. Some examples include synchronization of quantum clocks,
distributed QRNG beacons for smart contracting, etc. NOTE – QIN could be
defined as any network that incorporates quantum communication technologies for
the purpose of transporting quantum states.

In particular, the content of this technical report includes use cases of
quantum network beyond QKDN in various relevant fields of application and
provides an analysis of their technical advantages, key enabling technologies,
maturity and application prospects.

Draft Supplement ITU-T Y.supp.QKDN-UC “Use cases of quantum key distribution
networks” in TD159-WP3 This Supplement presents use cases of quantum key
distribution (QKD) networks. In particular, the scope of this Supplement
includes:

- Competitive advantage brought by QKDN;
- Overview of QKDN use cases;
- Analysis of collected QKDN use cases including categorization.

Draft Recommendation ITU-T Y.QKDN-AMC “Quantum key distribution networks -
Requirements and architectural model for autonomic management and control" in
TD160-WP3

To support the autonomic networking, cognitive networking and self-management
for improving the QoS in a quantum key distribution network (QKDN), this draft
Recommendation specifies the requirements and architectural model for autonomic
management and control (AMC) in QKDNs. In particular, the scope of this
Recommendation includes:

- Overview of AMC in QKDN;
- Requirements for AMC in QKDN;
- Consideration for cognition process of AMC in QKDN.
- Architectural model for AMC in QKDN;

Draft Recommendation ITU-T Y.QKDN_SSNreq “Functional requirements for
integration of quantum key distribution network and secure storage network" in
TD162-WP3

This Recommendation specifies functional requirements for integration of
quantum key distribution network and secure storage network. It includes
detailed description of the followings:

- functional requirements for SSN user plane;
- functional requirements for SSN control plane;
- functional requirements for SSN storage plane;
- functional requirements for SSN management plane.

Draft Recommendation ITU-T Y.QKDN_SSNarch “Functional architecture for
integration of quantum key distribution network and secure storage network" in
TD163-WP3 This draft Recommendation will study on functional architecture for
integration of quantum key distribution network and secure storage network. It
includes detailed description of the followings:

- functional architecture model;
- functional elements;
- reference points;
- share format and metadata;
- storage configuration;
- operational procedures.

5. Conclusion

SG13 will study the network aspects of QKD. Q16/13 looks forward to close
cooperation with ITU-T SG2, SG11, SG15, SG17, ETSI ISG-QKD, ISO/IEC JTC1/SC27,
AG4, IETF/IRTF, and relevant groups for future standardization on QKD networks.

Attachments:
1) The approved Recommendation ITU-T Y.3810 (ex Y.QKDN_iwfr) “Quantum key
distribution network interworking - framework”; 2) The approved Recommendation
ITU-T Y.3811 (ex Y.QKDN-qos-fa) “Quantum key distribution networks - Functional
architecture for quality of service assurance”; 3) The approved Recommendation
ITU-T Y.3812 (ex Y.QKDN-qos-ml-req) “Quantum key distribution networks -
Requirements for machine learning based quality of service assurance”; 4) The
consented draft Recommendation ITU-T Y.3813 (ex Y.QKDN-iwrq) “Quantum key
distribution networks interworking – functional requirements” (TD144/WP3); 5)
The consented draft Recommendation ITU-T Y.3814 (ex Y.QKDN-ml-fra) “Quantum key
distribution networks - functional requirements and architecture for machine
learning enablement” (TD145/WP3); 6) The updated draft Recommendation ITU-T
Y.QKDN-iwac “Quantum key distribution network interworking - architecture”
(TD146/WP3); 7) The updated draft Recommendation ITU-T Y.QKDN-rsfr “Framework
of quantum key distribution network resilience” (TD147/WP3); 8) The updated
draft Technical Report ITU-T TR-QEFN “ITU-T’s views for Quantum-Enabled Future
Networks” (TD148/WP3); 9) The updated draft Recommendation ITU-T Y.QKDNi_SDNC
“Quantum Key Distribution Network Interworking – Software Defined Networking
Control” (TD149/WP3); 10) The updated draft Recommendation ITU-T Y.QKDNf_fr
“Framework of Quantum Key Distribution Network Federation” (TD150/WP3); 11) The
updated draft Supplement Y.supp.QKDN-roadmap “Standardization roadmap on
Quantum Key Distribution Networks” (TD151/WP3); 12) The initial draft Technical
Report ITU-T TR-QN-UC “Use cases of quantum networks beyond QKDN” (TD158/WP3);
13) The initial draft Supplement ITU-T Y.supp.QKDN-UC “Use cases of quantum key
distribution networks” (TD159/WP3); 14) The initial draft Recommendation ITU-T
Y.QKDN-AMC “Quantum key distribution networks - Requirements and architectural
model for autonomic management and control" (TD160/WP3); 15) The initial draft
Recommendation ITU-T Y.QKDN_SSNreq “Functional requirements for integration of
quantum key distribution network and secure storage network" (TD162/WP3); 16)
The initial draft Recommendation ITU-T Y.QKDN_SSNarch “Functional architecture
for integration of quantum key distribution network and secure storage network"
(TD163/WP3).