A protocol upgrade method and system for a quantum key distribution metropolitan area network

Abstract

The application discloses a kind of protocol upgrade method and system of quantum key distribution metropolitan area network, belong to quantum key distribution network technical field;The method comprises the following steps: step S1: QKD metropolitan area network information inquiry;Step S2: protocol upgrade based on single path;Step S3: time slot resource scheduling.The protocol upgrade method of QKD metropolitan area network of the present application flexibly schedules the time slot resource of QKD metropolitan area network, reduces the deployment of additional fiber channel in the protocol upgrade process of QKD metropolitan area network;Solve the problems of time slot resource waste, channel cost increase and low time slot resource utilization rate that existing QKD metropolitan area network protocol upgrade faces, is favorable for improving QKD metropolitan area network protocol upgrade efficiency.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of quantum key distribution network, and particularly relates to a protocol upgrading method and system of a quantum key distribution metropolitan area network. BACKGROUND

[0002] A quantum key distribution (QKD) network can provide its users with unconditionally secure quantum keys, thereby ensuring the secure transmission of confidential and sensitive information. The quantum keys provided can resist attacks by powerful quantum computers in the future and do not depend on computational complexity. Existing QKD metropolitan area networks are mostly based on a single QKD protocol, especially the BB84 protocol. However, as QKD protocols continue to develop, researchers have proposed more and more QKD protocols, which have different advantages and disadvantages. The BB84 protocol has the characteristics of high key generation rate but low security level, the MDI protocol has the characteristics of low key generation rate but high security level, and the TF protocol has the characteristics of long transmission distance but high technical complexity. At present, there is no perfect QKD protocol. Therefore, the QKD metropolitan area network based on a single protocol gradually cannot meet the diversified needs of users, and the future QKD metropolitan area network will face a large number of protocol upgrading needs. However, different QKD protocols have compatibility and interoperability problems, and the current QKD metropolitan area network lacks an efficient protocol upgrading method. The use of a traditional stacking upgrading method will cause a large waste of time slot resources and require the deployment of a large number of additional optical fiber channels. Since optical fiber channels are relatively expensive, the use of the traditional stacking upgrading method for the protocol upgrading of the QKD metropolitan area network will bring extremely high costs, limiting the large-scale evolution and development of the QKD metropolitan area network. Therefore, how to fully utilize the time slot resources in the protocol upgrading process of the QKD metropolitan area network to reduce unnecessary optical fiber channel costs has become a key problem in the protocol upgrading of the QKD metropolitan area network, which has not been solved.

[0003] Existing QKD metropolitan area networks are mostly based on a single protocol and do not consider protocol upgrading in the long term at the beginning of construction. If a traditional method is used for protocol upgrading, multiple QKD devices and optical fiber channels of different protocols are deployed in parallel based on a stacking method, which is likely to cause high construction costs and a large amount of idle time slot resources on the optical fiber channels to be wasted. If protocol upgrading is not performed, the QKD metropolitan area network based on a single protocol can only provide a single type of key and is difficult to meet the diversified security needs of a large number of users in the metropolitan area. Therefore, not considering protocol upgrading will gradually be difficult to meet the security needs of users, and the protocol upgrading of the QKD metropolitan area network based on the traditional method will result in low utilization of time slot resources on the optical fiber channels and high protocol upgrading costs. SUMMARY

[0004] The application aims to provide a protocol upgrade method and system for a quantum key distribution metropolitan area network to solve the problems and achieve the effects in the background art.

[0005] The application is achieved by a protocol upgrade method for a quantum key distribution metropolitan area network, which comprises the following steps:

[0006] Step S1: QKD metropolitan area network information query;

[0007] Step S2: single-path-based protocol upgrade;

[0008] Step S3: time slot resource scheduling.

[0009] Preferably, the QKD metropolitan area network information query in step S1 comprises the following steps:

[0010] Step S1-1: query QKD metropolitan area network topology information;

[0011] Step S1-2: query optical channel information on each QKD link and QKD device information in each QKD node;

[0012] Step S1-3: query optional protocols of the QKD metropolitan area network, which are determined by the QKD metropolitan area network manager according to the available QKD devices;

[0013] Step S1-4: query the achievable key generation rate of each optional protocol on each QKD link;

[0014] Step S1-5: query original key service information in the QKD metropolitan area network;

[0015] Step S1-6: set the unit time and time slot size and query the occupation of time slot resources on each QKD link.

[0016] Preferably, the single-path-based protocol upgrade operation steps in step S2 are as follows:

[0017] Step S2-1: query the terminal node, QKD protocol and required key generation rate of the protocol upgrade request;

[0018] Step S2-2: perform routing calculation on the protocol upgrade request based on the K shortest path algorithm to obtain the first K paths with the shortest hop count;

[0019] Step S2-3: select a target path according to the connection mode of the target protocol;

[0020] Step S2-4: calculate the number of time slots on the optical channel that needs to be occupied by the target protocol in the QKD link contained in the selected target path;

[0021] Step S2-5: Calculate the total amount of time slot resources required for the QKD link in the selected target path after the protocol upgrade;

[0022] Step S2-6: Add new optical channels until the number of time slot resources lacking in the QKD link in the selected target path is less than the amount of time slot resources corresponding to a single channel; the amount of time slot resources corresponding to a single channel is the unit time ÷ time slot size;

[0023] Step S2-7: Add corresponding QKD devices to the nodes at both ends of the QKD link of the added channel;

[0024] Step S2-8: Allocate the time slot resources of the QKD link in the selected target path after adding the optical channel to the target protocol preferentially;

[0025] Step S2-9: Generate a running schedule for each QKD device corresponding to the target protocol and the original protocol;

[0026] Step S2-10: Record the QKD links affected by the original protocol and the time slot resources lacking thereof.

[0027] Preferably, the time slot resource scheduling in step S3 includes the following steps:

[0028] Step S3-1: Select K candidate paths between each pair of adjacent QKD nodes for which the original protocol lacks time slot resources based on the K shortest path algorithm;

[0029] Step S3-2: Select the candidate path that can provide the maximum key generation rate for the corresponding original protocol as the new path between the corresponding adjacent QKD nodes;

[0030] Step S3-3: Determine whether the time slot resources of the QKD link in the new path are sufficient for scheduling;

[0031] Step S3-4: For each new path between a pair of adjacent QKD nodes for which the time slot resources can be scheduled, perform time slot resource scheduling to allocate the time slot resources of the corresponding QKD link to the original protocol;

[0032] For each new path between a pair of adjacent QKD nodes for which the time slot resources cannot be scheduled, add an optical channel and a QKD device, and add the optical channel and the QKD device between the corresponding adjacent QKD nodes;

[0033] Step S3-5: Update the running schedule of each QKD device corresponding to the target protocol and the original protocol to complete the protocol upgrade of the QKD metropolitan area network.

[0034] Preferably, the terminal nodes include a source QKD node and a sink QKD node, the QKD protocol of the protocol upgrade request is the target protocol, and the target protocol involves different connection modes.

[0035] The connection mode includes "sending end -> receiving end", "receiving end <- sending end -> receiving end", and "sending end -> receiving end <- sending end".

[0036] Preferably, the step S2-3 of selecting the target path according to the connection mode of the target protocol specifically operates as follows:

[0037] If the connection mode of the target protocol is "receiving end <- sending end -> receiving end" or "sending end -> receiving end <- sending end", and the hop count of the shortest path is 1, the device of the connection mode cannot be deployed, and the path corresponding to the minimum hop count greater than 1 is selected as the target path.

[0038] If the connection mode of the target protocol is "sending end -> receiving end", the shortest path corresponding to the minimum hop count is directly selected as the target path.

[0039] A protocol upgrading system of a quantum key distribution metropolitan area network, characterized in that: the protocol upgrading includes the protocol upgrading method of the quantum key distribution metropolitan area network according to any one of claims 1 to 7; the protocol upgrading system includes a total control module for controlling the operation of the entire system, a QKD metropolitan area network information query module for querying detailed information and service information of the QKD metropolitan area network, a protocol upgrading module for implementing protocol upgrading of a single path of the QKD metropolitan area network, and a time slot resource scheduling module for scheduling time slot resources to compensate for the key demand of a QKD link lacking time slot resources.

[0040] Preferably, the QKD metropolitan area network information query module includes:

[0041] a topology query unit for querying QKD metropolitan area network topology information;

[0042] an optical channel and device query unit for querying optical channel information on each QKD link and QKD device information in each QKD node;

[0043] a time slot resource query unit for querying the occupation of time slot resources on each QKD link;

[0044] a setting unit for setting a unit time and a time slot size;

[0045] a service query unit for querying original key service information in the QKD metropolitan area network;

[0046] a protocol query unit for querying selectable protocols of the QKD metropolitan area network;

[0047] a key generation rate query unit for querying the key generation rate of each selectable protocol on each QKD link.

[0048] Preferably, the protocol upgrade module comprises:

[0049] A request query unit for querying a terminal node of a protocol upgrade request and a required key generation rate of a QKD protocol;

[0050] An optical channel adding unit for adding new optical channels until the number of time slots lacking in the QKD links in the selected target path is less than the number of time slots corresponding to a single channel;

[0051] A running schedule generating unit for generating a running schedule of each QKD device corresponding to the target protocol and the original protocol;

[0052] A time slot resource calculating unit for calculating the number of time slots on the optical channels required by the QKD links contained in the selected target path to be occupied by the target protocol;

[0053] A time slot resource allocating unit for preferentially allocating the time slot resources of the QKD links in the selected target path after adding the new optical channels to the target protocol;

[0054] A QKD device adding unit for adding corresponding QKD devices at the nodes at both ends of the QKD links of the added channels;

[0055] A routing unit for performing routing calculation on the protocol upgrade request based on a K shortest path algorithm to obtain the first K paths with the shortest hop counts;

[0056] A path screening unit for selecting a target path according to the connection mode of the target protocol;

[0057] A time slot resource recording unit for recording the QKD links affected by the original protocol and the time slot resources lacking in the QKD links;

[0058] The time slot resource scheduling comprises: a path selecting unit for selecting a to-be-selected path capable of providing the maximum key generation rate for the corresponding original protocol as a new path between the corresponding adjacent QKD nodes;

[0059] A time slot scheduling unit for performing time slot resource scheduling;

[0060] A path key generation rate calculating unit for calculating the key generation rate of a path;

[0061] A judging unit for judging whether the time slot resources of the QKD links in the new path are sufficient for scheduling;

[0062] A running schedule updating unit for updating the running schedule of each QKD device corresponding to the target protocol and the original protocol.

[0063] Compared with the prior art, the present application has the following improvements and advantages: 1. Through the protocol upgrade method of the QKD metropolitan area network, the time slot resources of the QKD metropolitan area network are flexibly scheduled, and the deployment of additional optical fiber channels of the QKD metropolitan area network in the protocol upgrade process is reduced; the problems of waste of time slot resources, increase of channel cost and low utilization rate of time slot resources in the protocol upgrade of the existing QKD metropolitan area network are solved, which is beneficial to improve the protocol upgrade efficiency of the QKD metropolitan area network.

[0064] 2. The protocol upgrade device of the QKD metropolitan area network triggered by the centralized control system, the protocol upgrade method of the QKD metropolitan area network is executed, the key generation rate and the QKD protocol demand of the QKD metropolitan area network protocol upgrade request are realized with lower channel cost, and the QKD metropolitan area network state is updated after the protocol upgrade is completed. BRIEF DESCRIPTION OF DRAWINGS

[0065] Figure 1 The overall flowchart of the method of the present application.

[0066] Figure 2 The flowchart of the QKD metropolitan area network information query in the present application.

[0067] Figure 3 The flowchart of the protocol upgrade based on a single path in the present application.

[0068] Figure 4 The flowchart of the time slot resource scheduling in the present application.

[0069] Figure 5 The module diagram of the system of the present application.

[0070] Figure 6 The QKD device setting diagram of the embodiment of the present application. DETAILED DESCRIPTION

[0071] The present application is further described below in combination with the drawings.

[0072] Reference Figures 1-4 A protocol upgrade method of a quantum key distribution metropolitan area network, the method comprising the following steps:

[0073] Step S1: QKD metropolitan area network information query; the QKD metropolitan area network information query specifically operates as follows:

[0074] Step S1-1: query the QKD metropolitan area network topology information;

[0075] Step S1-2: query the optical fiber channel information on each QKD link and the QKD device information in each QKD node;

[0076] Step S1-3: Query the optional protocol of the QKD metropolitan area network, which is determined by the QKD metropolitan area network manager according to the available QKD equipment;

[0077] Step S1-4: Query the key generation rate of each optional protocol on each QKD link;

[0078] Step S1-5: Query the original key service information in the QKD metropolitan area network;

[0079] Step S1-6: Set the unit time and time slot size and query the occupation of the time slot resource on each QKD link.

[0080] Step S2: Single-path-based protocol upgrade; the single-path-based protocol upgrade is specifically operated as follows:

[0081] Step S2-1: Query the terminal node, QKD protocol and required key generation rate of the protocol upgrade request; the terminal node includes a source QKD node and a destination QKD node, and the QKD protocol of the protocol upgrade request is the target protocol, which can involve different connection modes, such as "sending end→ receiving end", "receiving end← sending end→ receiving end" and "sending end→ receiving end← sending end" modes.

[0082] Step S2-2: Perform routing calculation on the protocol upgrade request based on the K shortest path algorithm to obtain the first K paths with the shortest hop count; the obtained paths are the paths for transmitting the global key from one source QKD node of the protocol upgrade request to the destination QKD node hop by hop, and the value of K can be set by the QKD metropolitan area network manager according to the QKD metropolitan area network topology.

[0083] Step S2-3: Select the target path according to the connection mode of the target protocol;

[0084] If the connection mode of the target protocol is "receiving end← sending end→ receiving end" or "sending end→ receiving end← sending end", if the hop count of the shortest path is 1, the device of the connection mode cannot be deployed, and the path corresponding to the minimum hop count greater than 1 in the K paths is selected as the target path; if the connection mode of the target protocol is "sending end→ receiving end", the shortest path corresponding to the minimum hop count is directly selected as the target path.

[0085] Step S2-4: Calculate the number of time slots on the optical fiber channel occupied by the QKD link contained in the selected target path and required by the target protocol; the number of time slots required by the target protocol can be calculated by the key generation rate of the target protocol required by the protocol upgrade request ÷ the target protocol generation rate that can be achieved on the QKD link ÷ the time slot size.

[0086] Step S2-5: Calculate the total amount of time slot resources required for the QKD link in the selected target path after the protocol upgrade; the total amount of time slot resources includes the number of time slots required by the original protocol and the number of time slots required by the target protocol.

[0087] Step S2-6: Add new optical channel until the number of time slot resources lacking in the QKD link in the selected target path is less than the amount of time slot resources corresponding to a single channel, i.e. unit time ÷ time slot size; when the number of time slot resources lacking is less than the amount of time slot resources corresponding to a single channel, it is more reasonable to schedule the time slot resources on other QKD links, because the amount of idle time slot resources on a single QKD link cannot be greater than the amount of time slot resources corresponding to a single channel.

[0088] Step S2-7: Add corresponding QKD devices to the nodes at both ends of the QKD link of the new channel;

[0089] Step S2-8: Allocate the time slot resources of the QKD link in the selected target path after adding the new optical channel to the target protocol first; since the connection mode of the original protocol is usually "sender → receiver", this mode is more convenient for time slot resource scheduling than the other two modes, so the number of time slots required by the target protocol is satisfied first, and then the number of time slots required by the original protocol is satisfied as much as possible through time slot resource scheduling in step S3, which means that the key demand on the QKD link lacking time slot resources is supplemented by using the time slot resource generation amount of other QKD links.

[0090] Step S2-9: Generate a running schedule for each QKD device corresponding to the target protocol and the original protocol; the running schedule is a planning of the running time of the QKD device within a unit time, and each QKD device runs the specified QKD protocol or is bypassed within its planned running time.

[0091] Step S2-10: Record the QKD links affected by the original protocol and the time slot resources lacking thereof.

[0092] Step S3: Time slot resource scheduling; the specific operation of time slot resource scheduling includes the following steps:

[0093] Step S3-1: Select K candidate paths between each pair of adjacent QKD nodes for which the original protocol lacks time slot resources based on the K shortest path algorithm;

[0094] Step S3-2: Select the candidate path that can provide the maximum key generation rate for the corresponding original protocol as the new path between the corresponding adjacent QKD nodes;

[0095] Step S3-3: Determine whether the time slot resources of the QKD link in the new path are sufficient for scheduling;

[0096] Step S3-4: for each new path between each pair of adjacent QKD nodes that can schedule time slot resources, perform time slot resource scheduling to allocate time slot resources corresponding to the QKD link to the original protocol;

[0097] For each new path between each pair of adjacent QKD nodes that cannot schedule time slot resources, add a new optical channel and a new QKD device between the corresponding adjacent QKD nodes;

[0098] Step S3-5: update the running schedule of each QKD device corresponding to the target protocol and the original protocol to complete the protocol upgrade of the QKD metropolitan area network.

[0099] As shown in Figure 5 A protocol upgrade system for a quantum key distribution metropolitan area network, comprising a total control module for controlling the operation of the entire system, a QKD metropolitan area network information query module for querying detailed information and service information of the QKD metropolitan area network, a protocol upgrade module for implementing single-path QKD metropolitan area network protocol upgrade, a time slot resource scheduling module for scheduling time slot resources to compensate for the key demand of QKD links lacking time slot resources.

[0100] The QKD metropolitan area network information query module specifically comprises a topology query unit, an optical channel and device query unit, a time slot resource query unit, a setting unit, a service query unit, a protocol query unit, and a key generation rate query unit. The topology query unit is used to query QKD metropolitan area network topology information; the optical channel and device query unit is used to query optical channel information on each QKD link and QKD device information in each QKD node; the time slot resource query unit is used to query the occupation of time slot resources on each QKD link; the setting unit is used to set the unit time and time slot size; the service query unit is used to query original key service information in the QKD metropolitan area network; the protocol query unit is used to query selectable protocols of the QKD metropolitan area network; and the key generation rate query unit is used to query the achievable key generation rate of each selectable protocol on each QKD link.

[0101] The protocol upgrade module specifically comprises a request query unit, a fiber channel adding unit, a running schedule generating unit, a time slot resource calculating unit, a time slot resource allocating unit, a QKD device adding unit, a routing unit, a path screening unit, and a time slot resource recording unit. The request query unit is configured to query the terminal node of the protocol upgrade request, the QKD protocol, and the required key generation rate. The fiber channel adding unit is configured to add new fiber channels until the number of time slots lacking in the QKD links in the selected target path is less than the number of time slots corresponding to a single channel. The running schedule generating unit is configured to generate a running schedule of each QKD device corresponding to the target protocol and the original protocol. The time slot resource calculating unit is configured to calculate the number of time slots on the fiber channels occupied by the target protocol in the QKD links contained in the selected target path. The time slot resource allocating unit is configured to allocate the time slot resources of the QKD links in the selected target path after the addition of the new fiber channels to the target protocol in priority. The QKD device adding unit is configured to add corresponding QKD devices at the nodes at both ends of the QKD links of the new channels. The routing unit is configured to perform routing calculation on the protocol upgrade request based on the K shortest path algorithm to obtain the first K paths with the shortest number of hops. The path screening unit is configured to select a target path according to the connection mode of the target protocol. The time slot resource recording unit is configured to record the QKD links affected by the original protocol and the time slot resources lacking in the QKD links.

[0102] The time slot resource scheduling module specifically comprises a path selection unit, a time slot scheduling unit, a path key generation rate calculating unit, a judging unit, and a running schedule updating unit. The path selection unit is configured to select a to-be-selected path capable of providing the maximum key generation rate for the corresponding original protocol as a new path between the corresponding adjacent QKD nodes. The time slot resource scheduling unit is configured to perform time slot resource scheduling. The path key generation rate calculating unit is configured to calculate the key generation rate of the path. The judging unit is configured to judge whether the time slot resources of the QKD links in the new path are sufficient for scheduling. The running schedule updating unit is configured to update the running schedule of each QKD device corresponding to the target protocol and the original protocol.

[0103] As shown in Figure 6 , it is a preferred embodiment of the application.

[0104] In this embodiment, eight QKD transceivers are used as QKD devices. First, the information of the QKD metropolitan area network is queried. The topology information of the QKD metropolitan area network is queried, and eight nodes (nodes 1-8) and nine links ((1-2), (2-3), (3-4), (4-5), (1-6), (2-6), (3-7), (5-8), and (7-8)) are obtained.

[0105] Query the fiber channel information on each QKD link 1 (1-2), 1 (2-3), 1 (3-4), 1 (4-5), 1 (1-6), 1 (2-6), 1 (3-7), 1 (5-8), 1 (7-8) and the QKD device information in each QKD node 2 pairs of QKD transceivers, node 1, 2 pairs of QKD transceivers node 2, 2 pairs of QKD transceivers, node 3, 1 pair of QKD transceivers, node 4, 2 pairs of QKD transceivers, node 5, 1 pair of QKD transceivers, node 6, 1 pair of QKD transceivers, node 7, 1 pair of QKD transceivers, node 8, 1 pair of QKD transceivers.

[0106] Query the QKD metropolitan area network optional protocol (BB84, MDI): Query the key generation rate that can be achieved on each QKD link for each optional protocol 40 kbps (BB84 1-2), 42 kbps (BB84 2-3), 43 kbps (BB84 3-4), 38 kbps (BB84 4-5), 44 kbps (BB84 1-6), 40 kbps (BB84 2-6), 39 kbps (BB84 3-7), 41 kbps (BB84 5-8), 41 kbps (BB84 7-8), 20 kbps (MDI 1-3), 18 kbps (MDI 1-4), 15 kbps (MDI 1-5), 19 kbps (MDI 2-4), 17 kbps (MDI 2-5), 21 kbps (MDI 3-5).

[0107] Query the key generation rate that can be achieved on each QKD link for each optional protocol 40 kbps (BB84 1-2), 42 kbps (BB84 2-3), 43 kbps (BB84 3-4), 38 kbps (BB84 4-5), 44 kbps (BB84 1-6), 40 kbps (BB84 2-6), 39 kbps (BB84 3-7), 41 kbps (BB84 5-8), 41 kbps (BB84 7-8), 20 kbps (MDI 1-3), 18 kbps (MDI 1-4), 15 kbps (MDI 1-5), 19 kbps (MDI 2-4), 17 kbps (MDI 2-5), 21 kbps (MDI 3-5).

[0108] Set the time unit 1s and the time slot size 0.01s, and query the occupation of the time slot resource on each QKD link 90 / 100 (1−2), 48 / 100 (2−3), 47 / 100 (3−4), 53 / 100 (4−5), 41 / 100 (1−6), 40 / 100 (2−6), 90 / 100 (3−7), 98 / 100 (5−8), 98 / 100 (7−8).

[0109] Based on the single-path protocol upgrade, the terminal nodes of the protocol upgrade request are queried: QKD node 1, QKD node 5, QKD protocol (MDI protocol), and the required key generation rate (5 kbps). Based on the K shortest path algorithm, the protocol upgrade request is routed to obtain the first K with the shortest hop count, and here K takes two paths 1−2−3−4−5 and 1−6−2−3−4−5; according to the connection mode of the target protocol, the target path 1−2−3−4−5 is selected.

[0110] The number of time slots on the fiber channel occupied by the target protocol is calculated (33 (1−2), 33 (2−3), 33 (3−4), 33 (4−5)) for the QKD link contained in the selected target path. The total amount of time slot resources required by the QKD link in the selected target path after the protocol upgrade is calculated (123 (1−2), 81 (2−3), 80 (3−4), 86 (4−5)). New fiber channels are added until the number of time slot resources lacking for the QKD link in the selected target path is less than the amount of time slot resources corresponding to a single channel. The corresponding QKD devices are added to the nodes at both ends of the QKD link of the added channel. The time slot resources of the QKD link in the selected target path after the addition of the new fiber channel are preferentially allocated to the target protocol. The operation schedule of the QKD devices corresponding to the target protocol and the original protocol is generated: repeat every 1s, 0−0.33s MDI, 0.33−1s BB84 (sender 1a), 0−0.33s bypass, 0.33−1s BB84 (receiver 2a), 0−0.33s bypass, 0.33−0.81s BB84 (sender 2a), 0−0.33s MDI, 0.33−0.81s BB84 (receiver 3a), 0−0.33s bypass, 0.33−0.8s BB84 (sender 3a), 0−0.33s bypass, 0.33−0.8s BB84 (receiver 4a), 0−0.33s bypass, 0.33−0.6s BB84 (sender 4a), 0−0.33s bypass, 0.33−0.86s BB84 (receiver 5a), 0−0.33s MDI (sender 5a), 0−0.41s BB84 (sender 1b), 0−0.41s BB84 (receiver 6a), 0−0.4s BB84 (sender 6a), 0−0.4s BB84 (receiver 2b), 0−0.9s BB84 (sender 3b), 0−0.9s BB84 (receiver 7a), 0−0.98s BB84 (sender 7a), 0−0.98s BB84 (receiver 8a), 0−0.98s BB84 (sender 8a), 0−0.98s BB84 (receiver 5b)). The affected QKD link of the original protocol and the time slot resources lacking therefrom are recorded (23s (1−2)).

[0111] Time slot resource scheduling. Based on the K shortest path algorithm, K candidate paths are selected for each pair of adjacent QKD nodes in the original protocol whose time slot resources are insufficient, and there is only one candidate path 1-6-2. The candidate path that can provide the maximum key generation rate (24 kbps) for the corresponding original protocol is selected as the new path (1-6-2) between the corresponding adjacent QKD nodes. It is judged whether the time slot resources of the QKD links in the new path are sufficient for scheduling (the time slot resources required to be scheduled by the QKD links in the new path: 21 (1-6), 23 (2-6), the free time slot resources of the QKD links in the new path: 59 (1-6), 60 (2-6), so it is sufficient for scheduling. Time slot resource scheduling is performed. The running schedule of each QKD device corresponding to the target protocol and the original protocol is updated: repeat every 1s, 0-0.33s MDI, 0.33-1s BB84 (transmitter 1a), 0-0.33s bypass, 0.33-1s BB84 (receiver 2a), 0-0.33s bypass, 0.33-0.81s BB84 (transmitter 2a), 0-0.33s MDI, 0.33-0.81s BB84 (receiver 3a), 0-0.33s bypass, 0.33-0.8s BB84 (transmitter 3a), 0-0.33s bypass, 0.33-0.8s BB84 (receiver 4a), 0-0.33s bypass, 0.33-0.86s BB84 (transmitter 4a), 0-0.33s bypass, 0.33-0.86s BB84 (receiver 5a), 0-0.33s MDI (transmitter 5a), 0-0.62s BB84 (transmitter 1b), 0-0.62s BB84 (receiver 6a), 0-0.63s BB84 (transmitter 6a), 0-0.63s BB84 (receiver 2b), 0-0.9s BB84 (transmitter 3b), 0-0.9s BB84 (receiver 7a), 0-0.98s BB84 (transmitter 7a), 0-0.98s BB84 (receiver 8a), 0-0.98s BB84 (transmitter 8a), 0-0.98s BB84 (receiver 5b), and the protocol upgrade of the QKD metropolitan area network is completed.

[0112] Working principle: the protocol upgrade device of the QKD metropolitan area network which is coordinated by time slot resource scheduling and optical bypass technology can be realized in the centralized management system of the network; the QKD metropolitan area network operator sends a protocol upgrade request to the centralized control system, the centralized control system triggers the protocol upgrade device of the QKD metropolitan area network, executes the protocol upgrade method of the QKD metropolitan area network, realizes the key generation rate and QKD protocol requirements of the QKD metropolitan area network protocol upgrade request with lower channel cost, and is used for updating the QKD metropolitan area network state after the protocol upgrade is completed.

[0113] The protocol upgrade cost of the QKD metropolitan area network is reduced by time slot resource scheduling. The proposed protocol upgrade method of the QKD metropolitan area network is realized by QKD metropolitan area network information query, single-path-based protocol upgrade and time slot resource scheduling, and the proposed protocol upgrade device of the QKD metropolitan area network is used to realize the protocol upgrade method of the QKD metropolitan area network in a centralized manner. The present application can flexibly schedule the time slot resources of the QKD metropolitan area network, to a certain extent, reduce the deployment of additional optical fiber channels of the QKD metropolitan area network in the protocol upgrade process, solve the problems of time slot resource waste, increased channel cost and low time slot resource utilization rate of the existing QKD metropolitan area network protocol upgrade, and improve the protocol upgrade efficiency of the QKD metropolitan area network.

[0114] The above only describes the embodiments of the present application and is not used to limit the present application. The present application can have various changes and variations for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the scope of claims of the present application.

Claims

1. A method for upgrading a quantum key distribution metropolitan area network, characterized in that: The method comprises the following steps: Step S1: QKD metropolitan area network information query; Step S2: Single-path-based protocol upgrade; The single-path-based protocol upgrade operation steps are: Step S2-1: Query the terminal node, QKD protocol and required key generation rate of the protocol upgrade request; Step S2-2: Perform routing calculation on the protocol upgrade request based on the K shortest path algorithm to obtain the first K paths with the shortest hop count; Step S2-3: Select a target path according to the connection mode of the target protocol; The terminal node comprises a source QKD node and a destination QKD node, and the QKD protocol of the protocol upgrade request is the target protocol, and the target protocol involves different connection modes; Step S2-4: Calculate the number of time slots on the optical fiber channel that needs to be occupied by the target protocol for the QKD link contained in the selected target path; Step S2-5: Calculate the total amount of time slot resources required for the QKD link in the selected target path after the protocol upgrade; Step S2-6: Add new optical fiber channels until the number of time slot resources lacking in the QKD link in the selected target path is less than the time slot resource amount corresponding to a single channel; the time slot resource amount corresponding to a single channel is unit time ÷ time slot size; Step S2-7: Add corresponding QKD devices to the nodes at both ends of the QKD link of the added channel; Step S2-8: Preferentially allocate the time slot resources of the QKD link in the selected target path after adding the optical fiber channel to the target protocol; Step S2-9: Generate a running schedule for each QKD device corresponding to the target protocol and the original protocol; Step S2-10: Record the QKD link affected by the original protocol and the time slot resources lacking thereof; Step S3: Time slot resource scheduling.

2. The method of claim 1, wherein the method further comprises: The QKD metropolitan area network information query in the step S1 comprises the following steps: Step S1-1: Query the QKD metropolitan area network topology information; Step S1-2: Query the optical fiber channel information on each QKD link and the QKD device information in each QKD node; Step S1-3: Query the selectable protocols of the QKD metropolitan area network, which are determined by the QKD metropolitan area network manager according to the available QKD devices; Step S1-4: Query the key generation rate achievable by each selectable protocol on each QKD link; Step S1-5: Query the original key service information in the QKD metropolitan area network; Step S1-6: Set the unit time and time slot size and query the occupation of the time slot resources on each QKD link.

3. The method of claim 1, wherein the method further comprises: receiving a request for a protocol upgrade from a quantum key distribution metropolitan area network node; and sending a response to the request for the protocol upgrade to the quantum key distribution metropolitan area network node. The time slot resource scheduling in the step S3 comprises the following steps: Step S3-1: Select K candidate paths between each pair of adjacent QKD nodes for which the original protocol lacks time slot resources based on the K shortest path algorithm; Step S3-2: Select the candidate path that can provide the maximum key generation rate for the corresponding original protocol as the new path between the corresponding adjacent QKD nodes; Step S3-3: Judge whether the time slot resources of the QKD link in the new path are sufficient for scheduling; Step S3-4: For the new path between each pair of adjacent QKD nodes for which the time slot resources can be scheduled, perform time slot resource scheduling to allocate the time slot resources of the corresponding QKD link to the original protocol; For each pair of adjacent QKD nodes that cannot schedule time slot resources, a new optical channel and a QKD device are added between the corresponding adjacent QKD nodes; Step S3-5: updating the running schedules of the QKD devices corresponding to the target protocol and the original protocol, and completing the protocol upgrade of the QKD metropolitan area network.

4. The method of claim 2, wherein the method further comprises: The QKD metropolitan area network includes one or more original key services, each of which involves terminal nodes of the original key service, i.e., source QKD nodes and destination QKD nodes, a QKD protocol, and a required key generation rate, and the QKD protocol is an original protocol before the protocol upgrade.

5. The method of claim 1, wherein the method further comprises: receiving a request for a protocol upgrade from a quantum key distribution metropolitan area network node; and sending a response to the request for the protocol upgrade to the quantum key distribution metropolitan area network node. The specific operation of selecting a target path according to the connection mode of the target protocol in step S2-3 is as follows: If the connection mode of the target protocol is "receiving end←sending end→receiving end" or "sending end→receiving end←sending end", and the number of hops of the shortest path is 1, the device of the connection mode cannot be deployed, and the path corresponding to the minimum number of hops greater than 1 in the K paths is selected as the target path; If the connection mode of the target protocol is "sending end→receiving end", the shortest path corresponding to the minimum number of hops is directly selected as the target path. 6.A protocol upgrade system of a quantum key distribution metropolitan area network, characterized in that: The protocol upgrade system is used for the protocol upgrade method of the quantum key distribution metropolitan area network according to any one of claims 1 to 5; The protocol upgrade system includes a total control module for controlling the operation of the entire system, a QKD metropolitan area network information query module for querying detailed information and service information of the QKD metropolitan area network, a protocol upgrade module for implementing single-path QKD metropolitan area network protocol upgrade, and a time slot resource scheduling module for scheduling time slot resources to compensate for the key demand of the QKD link lacking time slot resources.

7. The protocol upgrade system of a quantum key distribution metropolitan area network according to claim 6, characterized in that: The QKD metropolitan area network information query module includes: a topology query unit for querying QKD metropolitan area network topology information; an optical channel and device query unit for querying optical channel information on each QKD link and QKD device information in each QKD node; a time slot resource query unit for querying the occupation of time slot resources on each QKD link; a setting unit for setting the unit time and the time slot size; a service query unit for querying original key service information in the QKD metropolitan area network; a protocol query unit for querying selectable protocols of the QKD metropolitan area network; a key generation rate query unit for querying the key generation rate of each selectable protocol on each QKD link.

8. The protocol upgrade system of a quantum key distribution metropolitan area network according to claim 7, characterized in that: The protocol upgrade module includes: a request query unit for querying the terminal nodes of the protocol upgrade request and the key generation rate required by the QKD protocol; an optical channel adding unit for adding new optical channels until the number of time slot resources lacking in the selected target path is less than the time slot resource amount corresponding to a single channel; a running schedule generation unit for generating the running schedules of the QKD devices corresponding to the target protocol and the original protocol; a time slot resource calculation unit for calculating the number of time slot resources on the optical channel that needs to be occupied by the target protocol in the QKD link included in the selected target path; The time slot resource allocation unit is configured to preferentially allocate time slot resources of the QKD link in the selected target path after adding the new fiber channel to the target protocol; The QKD device adding unit is configured to add corresponding QKD devices at nodes at both ends of the QKD link of the added channel; The routing unit is configured to perform routing calculation on the protocol upgrade request based on the K shortest path algorithm to obtain the first K paths with the shortest hop counts; The path screening unit is configured to select a target path according to a connection mode of the target protocol; The time slot resource recording unit is configured to record the QKD link of the original protocol affected and the lack of time slot resources thereof; The time slot resource scheduling includes: a path selection unit configured to select a to-be-selected path capable of providing the maximum key generation rate for the corresponding original protocol as a new path between corresponding adjacent QKD nodes; The time slot scheduling unit is configured to perform time slot resource scheduling; The path key generation rate calculation unit is configured to calculate the key generation rate of the path; The judging unit is configured to judge whether the time slot resources of the QKD link in the new path are sufficient for scheduling; The running schedule updating unit is configured to update the running schedules of the QKD devices corresponding to the target protocol and the original protocol.

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