Page 54 - Kaleidoscope Academic Conference Proceedings 2021

pair of QKD modules connected by a QKD link generates Defined Networking (SDN) controller and overall
keys in its own way. Generated keys are transferred to KMs. operational procedures of SDN control. SDN [16] has
The KMs manage the keys and supply them to cryptographic several advantages over traditional communication networks.
applications in the service layer of the user network. The On the one hand, the SDN controller supports centralized,
keys can be relayed via KMs and shared between any programmable, and hierarchical control; on the other hand, it
designated QKD nodes. The QKDN controller performs can provide fast services for applications by opening
routing control of key relay. The QKDN manager monitors northbound interfaces between the control layer and the
the status of the whole of the QKDN and supports key life service layer. The change of a control method by SDN in a
cycle management for the KMs, as well as routing and QKDN provides an alternative method to realizing control
rerouting control of key relay for the QKDN controller. functionalities by introducing logically centralized and
programmable control of network resources through
3.1.5 ITU-T Y.3804- Quantum key distribution networks standardized interfaces and protocols.
– Control and management
Figure 5 illustrates the hierarchical SDN controller in a
To realize secure, stable, efficient, and robust operations of QKDN. Under such scenarios, SDN controllers are
and services by a QKDN, as well as to manage a QKDN as organized in a hierarchical way, and the functions and
a whole and support user network management, ITU-T implementations of each SDN controller is independent of
Y.3804 [14] specifies functions and procedures for QKDN each other. The hierarchical controller is responsible for
control and management based on the requirements specified service provisioning within its control range. The SDN
in ITU T Y.3801. More specific functions are: controller of each layer has its northbound interface to
・ control and management specific functions (e.g. path communicate with the service layer, and the first layer has a
southbound interface for controlling the controllable
computation for routing control, session control
including access traffic steering/switching/splitting for elements and collecting information from the key
management layer and the quantum layer.
session control, QoS and charging policy control,
FCAPS management for each layer);
・ control and management reference points 3 rd layer SDN Controller
among/between control and management functional
components and those of other layers;
2 nd layer SDN 2 nd layer SDN
・ control and management orchestration functions of Controller C AB Controller C CD
multilayers. QKDN management layer includes
multiple functional components responsible for 1 st layer SDN 1 st layer SDN 1 st layer SDN 1 st layer SDN
multilayers (quantum, key management, and QKDN Controller C A Controller C B Controller C c Controller C D
control layers) and cross-layer management
orchestration; Sub-QKDN Sub-QKDN Sub-QKDN Sub-QKDN
D
C
B
A
・ interworking functions with external management
systems especially user network management systems, Figure 5 – Hierarchical SDN controller in a QKDN
the management capability exposure function, etc.
Unlike other traditional operational procedures of QKD
Each layer has a layer specific control and management network functions without SDN control, the operational
function associated with a corresponding management procedures of SDN control in a QKDN reduce the time for
function in the QKDN management layer. Each layer provisioning different services using SDN control by
specific control and management function provides a skipping the QKDN manager. The SDN controller can also
management agent capability between each layer provide more efficient key resource utilization by deciding
management function of the QKDN manager and its the end of key generation and controlling the management
respective layer functions. A cross-layer management monitor in a global view. In addition, the SDN technology
orchestration function provides orchestration capability improves the flexibility of service provisioning and provides
among multiple layer management functions. Reference services for applications in a fast way by opening the north-
points are defined as standard interfaces between the QKDN bound interface between the QKDN control layer and the
controller(s) and the functional components under control for service layer. With regard to a SDN-enabled QKDN, ETSI
the purpose of QKDN control, as well as standard interfaces has published the specification on a control interface for
between the QKDN manager and the functional components SDN in a QKDN [17].
under management for the purpose of QKDN management.
3.1.7 ITU-T Y.3806 – Quantum key distribution networks
3.1.6 ITU-T Y.3805- Quantum Key Distribution – Requirements for QoS assurance (Y.QKDN-qos-
Networks - Software Defined Networking Control req)
(Y.QKDN-SDNC)
ITU-T Y.3806 [18] specifies the high-level and functional
ITU-T Y.3805 [15] specifies the requirements, a functional requirements of QoS assurance for a QKDN. The functional
architecture, reference points, a hierarchical Software

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