In quantum key distribution (QKD) metropolitan area networks (MANs), the tidal effect of traffic, which is caused by the imbalanced distribution of users, decreases network resource utilization and leads to an imbalanced distribution of quantum keys. Additionally, there is noise interference when both classical and quantum signals are transmitted together within the same optical fiber. To solve these problems while considering the specific requirements of the services, we propose heuristic routing and wavelength allocation algorithm. Firstly, the routing scheme based on Minimization of Network Load Standard Deviation (MNLSD) is applied to balance traffic, reduce blocking rate, and achieve the goal of balancing secure key rate of QKD system. Based on this, we design a wavelength allocation scheme by Priority Based on Noise Influence (PBNI), which is applied to the scenarios where quantum channels are fixed but classical services dynamically arrive. It achieves noise suppression by flexibly scheduling classical services. Simulation results shows that MNLSD can reduce the standard deviation of link load up to 83.9% and the blocking rate up to 20% compared to benchmark scheme. Additionally, when compared to benchmark scheme, PBNI can improve the secure key rate of QKD system up to 127.3%.
In quantum key distribution (QKD) metropolitan area networks (MANs), the tidal effect of traffic, which is caused by the imbalanced distribution of users, decreases network resource utilization and leads to an imbalanced distribution of quantum keys. Additionally, there is noise interference when both classical and quantum signals are transmitted together within the same optical fiber. To solve these problems while considering the specific requirements of the services, we propose heuristic routing and wavelength allocation algorithm. Firstly, the routing scheme based on Minimization of Network Load Standard Deviation (MNLSD) is applied to balance traffic, reduce blocking rate, and achieve the goal of balancing secure key rate of QKD system. Based on this, we design a wavelength allocation scheme by Priority Based on Noise Influence (PBNI), which is applied to the scenarios where quantum channels are fixed but classical services dynamically arrive. It achieves noise suppression by flexibly scheduling classical services. Simulation results shows that MNLSD can reduce the standard deviation of link load up to 83.9% and the blocking rate up to 20% compared to benchmark scheme. Additionally, when compared to benchmark scheme, PBNI can improve the secure key rate of QKD system up to 127.3%.
To address the service blocking caused by imbalanced key resource distribution in quantum networks, this paper proposes a dynamic multidimensional key-aware routing (DMKAR) algorithm and further proposes a key-aware joint wavelength and routing resource allocation (KAJWR) algorithm based on the DMKAR algorithm. By implementing key-aware routing selection and key-aware wavelength allocation, we effectively ensure balanced utilization and generation of quantum key resources. Simulations show DMKAR reduces the service blocking rate by 49.9% versus traditional routing algorithms. Notably, KAJWR achieves a further 25.4% reduction in this rate compared to DMKAR and performs better in the balancing of key resource.
Quantum key distribution (QKD) has great potential in ensuring data security. Deploying QKD-related devices in existing optical fiber networks is a cost-effective way to practically implement QKD. However, QKD optical networks (QKDON) have a low quantum key generation rate and limited wavelength channels for data transmission. The simultaneous arrival of multiple QKD services may also lead to wavelength conflicts in QKDON. Therefore, we propose a resource-adaptive routing scheme (RAWC) with wavelength conflicts to achieve load balancing and efficient utilization of network resources. Focusing on the impact of link load and resource competition, this scheme dynamically adjusts the link weights and introduces the wavelength conflict degree. Simulation results indicate that the RAWC algorithm is an effective approach to solving the wavelength conflict problem. Compared with the benchmark algorithms, the RAWC algorithm can improve service request success rate (SR) by up to 30%.
Currently, with the continuous advancement of network and communication technology, the amount of data carried by the optical network is very huge. The security of high-speed and large-capacity information in optical networks has attracted more and more attention. Quantum key distribution (QKD) provides information-theoretic security based on the laws of quantum mechanics. Introducing QKD into an optical network can greatly improve the security of the optical network. In order to reduce the cost of deployment on QKD infrastructure, quantum signals in QKD and classical signals in optical networks are multiplexed in the same fiber by wavelength-division manner. Moreover, due to the limited wavelength resources in an optical fiber, time-division technology is adopted to construct different kinds of channels in QKD system for efficient utilization of wavelength resources. Under such situation, how to satisfy the security requirements of service requests and complete the efficient scheduling of multi-dimensional resources, i.e., wavelengths and timeslots, is a challenging problem. This paper addresses this problem by considering multi-dimensional routing, wavelength, and timeslot allocation (RWTA) in short-distance quantum key distribution optical networks (QKD-ON), in which any two nodes can directly establish a quantum channel, and the maximum distance between any two nodes is less than the distance that can carry out point-to-point quantum key distribution process. While accommodating services with security requirements in QKD optical networks, to avoid the wavelength time-slot fragmentation caused by the constraints of wavelength consistency and time-slot continuity, we propose a time-window-based security orchestration strategy as well as relative-loss of time continuous compactness based RWTA strategy. We conducted the simulations under various scenarios, e.g., different key updating periods and different distributions on wavelength resources, etc., and the results show that the proposed strategy can achieve better performance compared with the baselines in terms of key success rate, key-updating delay, and blocking probability.
In quantum key distribution (QKD)-secured optical networks, blocking increases with the number of QKD lightpath requests as well as with the number of times modification required to improve the security level of QKD lightpath requests. The blocking is severe problem in such networks because of the limited number of resources (wavelengths and time-slots) in each fiber link. In this paper, we propose a priority order-based routing wavelength and time-slot allocation (POB-RWTA) scheme to reduce the blocking of QKD lightpath requests. In the proposed POB-RWTA scheme, the QKD lightpath requests are served according to their priority order. The priority order of each QKD lightpath request is based on the security level. The blocking of high priority lightpath requests (HPLRs) and total incoming QKD lightpath requests due to limited resources can be reduced using the above criterion of priority order. The performance analysis of the proposed POB-RWTA scheme is made in terms of the success probability of QKD lightpath requests considering different wavelengths for QSCh and the probability of secret key update failure. We compared the proposed POB-RWTA scheme with a non-priority order-based routing wavelength and time-slot allocation (NPOB-RWTA) scheme. Simulations performed on NSFNET topology show that by using the POB-RWTA scheme, the success probability of HPLRs and total incoming QKD lightpath requests are significantly improved as compared to NPOB-RWTA.
Optical communications provide high capacity and scalability, while quantum communications, particularly through quantum key distribution (QKD), enable information-theoretic security. However, it still remains challenging to deliver both high throughput communication and long-term security within a hybrid quantum-classical optical network. Specifically, classical optical resources can be reallocated to support QKD, aiming to achieve synergistic resource utilization that surpasses the sum of individual functionalities. In this work, we formulate a networking model that captures the resource allocation constraints, aiming to figure out the necessary conversion of classical optical resources to QKD capacity while maintain the connectivity of classical optical communication. Based on that, we propose a synergistic resource allocation strategy, implemented through heuristic routing, wavelength assignment, and power configuration (SRWP) algorithms. Simulation results demonstrate that the proposed SRWP algorithm, with the objective of network-wide average secret key rate (SKR) maximization (SRWP-ARM), enhances the average SKR from the order of kbit/s to Mbit/s at GHz-level pulse repetition rates. In a 9-node mesh network topology with 50 km links, the algorithm achieves this gain with zero service blocking under a traffic load of 100 erlangs. At a higher load of 300 erlangs, it maintains a service blocking probability as low as 1.24% while still achieving an average SKR of 18.05 kbit/s. This represents the best trade-off between classical service connectivity and secret key generation across all evaluated algorithms.
Optical network security has attracted extensive attentions recently, data encryption is an effective way to enhance the security. Unlike conventional key distribution methods, Quantum key distribution (QKD) is provably-secure. Integrating QKD into optical networks can provide a new paradigm for secure communications. In a QKD integrated optical network, besides the traditional data channels, two additional channels, called quantum-signal channels and public interaction channels, are required to support secure key. Crucially, how to optimally allocate limited wavelength resources to the three channels is emerging as a novel problem. By introducing wavelength division multiplexing (WDM) network and defining the wavelength occupancy factor, this paper designs a dynamic routing, wavelength and time-slot allocation (DRWTA) algorithm for the wavelength allocation in QKD integrated optical network. The simulation results show wavelength scale factor has an adverse effect on the resource utilization rate and the blocking probability. Furthermore, the DRWTA algorithm provides a strategy to allocate wavelength for three types of channels in QKD-WDM networks. The success probability can be improved by exploiting the DRWTA algorithm.