A method and system for integrating CCN and TSN

Abstract

The application belongs to the technical field of network communication, and discloses a CCN and TSN fusion method and system. By designing unified traffic priority mapping and isolation rules, the ordered transmission of different types of traffic in the fusion network is realized, and traffic congestion is avoided. Through the CCN-TSN fusion node and the collaborative controller, the dynamic collaboration of the cache strategy and the TSN time slot scheduling strategy is realized, and the network resource utilization is improved. By filling the standardization blank of the fusion of the two, the TSN adaptation and expansion rules of the CCN protocol are formulated, and the landing and expansion of the fusion network are realized.

Description

Technical Field

[0001] This invention belongs to the field of network communication technology, specifically relating to a method and system for integrating CCN and TSN. Background Technology

[0002] With the rapid development of fields such as the Industrial Internet and intelligent connected vehicles, the application scenarios of information technology (IT) / operation technology (OT) convergence are becoming increasingly widespread. Network transmission needs to meet two key requirements at the same time: on the one hand, it needs to achieve deterministic low-latency transmission of hard real-time control flow, and on the other hand, it needs to complete the efficient distribution of massive non-real-time content streams.

[0003] Content-centric Networks (CCNs) are a novel network architecture designed for content distribution. They use content names as routing identifiers, employ an interest / data interaction model, and leverage intranet caching to achieve content retrieval based on proximity. CCNs effectively avoid the redundancy and duplication issues of traditional IP network end-to-end transmission, reduce backbone network bandwidth utilization, and are naturally suited for non-real-time scenarios such as massive content distribution, edge computing, and IoT data collection. However, CCNs themselves employ a best-effort transmission model, lacking mechanisms to guarantee time synchronization and deterministic latency, making it difficult to directly meet the transmission requirements of hard real-time control flows.

[0004] Time-Sensitive Networking (TSN) is built on the IEEE 802.1 standard family. It achieves network-wide nanosecond-level clock synchronization through the IEEE 802.1AS precise time protocol and utilizes deterministic scheduling mechanisms such as 802.1Qbv time-aware shaping and 802.1Qch cyclic queuing and forwarding to reserve precise time slots for critical traffic. This enables it to provide deterministic transmission services with zero packet loss and microsecond-level jitter, making it a core supporting technology for hard real-time scenarios such as industrial control and real-time audio / video. However, TSN lacks content caching and nearest-neighbor distribution capabilities. For massive non-real-time content streams, it still relies on an end-to-end hop-by-hop forwarding mode, resulting in significant bottlenecks in distribution efficiency and bandwidth utilization.

[0005] Given the inherent complementarity between CCN and TSN, merging them to build a unified bearer network is a feasible technical direction for adapting to IT / OT convergence scenarios. However, most existing convergence solutions remain at a simple superposition level, failing to achieve deep adaptation of underlying protocols and scheduling mechanisms, and mainly suffer from the following shortcomings:

[0006] First, there is a fundamental conflict between the stateless request-response model of CCN and the time-slotted deterministic scheduling of TSN. CCN's communication primitives do not participate in TSN's clock synchronization negotiation and lack the ability to sense and respond to clock drift, making it difficult for content request messages and corresponding data messages to be time-aligned within the same TSN scheduling window. At the same time, CCN traffic is characterized by burstiness and no reserved bandwidth, which can easily preempt the time slot resources of TSN real-time streams or be excessively blocked by the TSN scheduling mechanism, resulting in a decrease in overall network transmission efficiency.

[0007] Second, there is a lack of unified fusion nodes and collaborative control mechanisms. The existing caching strategies and TSN scheduling strategies are independent of each other and cannot be dynamically and collaboratively adjusted according to network conditions. This results in a lack of clear priority division and isolation rules between real-time control flow, real-time content flow and ordinary content flow, which easily leads to mutual interference between traffic and fails to achieve the expected goal of "one network carrying".

[0008] In addition, existing research such as D-NDNoT (Deterministic Named Data Networking of Things) combines deterministic scheduling mechanisms with Named Data Network (NDN) as an application layer protocol running on top of the TSN network. However, it is essentially still an overlay scheme at the protocol stack level and does not involve full-stack deep integration from naming, scheduling, data forwarding to the control plane. Summary of the Invention

[0009] To address the aforementioned technical issues, this invention provides a method and system for integrating CCN and TSN. By designing unified traffic priority mapping and isolation rules, it achieves orderly transmission of different types of traffic in the integrated network, avoiding traffic congestion. Through CCN-TSN integration nodes and a collaborative controller, it realizes dynamic coordination between caching strategies and TSN time slot scheduling strategies, improving network resource utilization. By filling the standardization gap in their integration, it formulates TSN adaptation and extension rules for the CCN protocol, making the integrated network feasible and scalable.

[0010] The present invention provides a method for fusing CCN and TSN, comprising: Protocol layer extension and adaptation: The CCN protocol is extended to achieve underlying adaptation with the TSN protocol; Network layer converged node deployment: Deploy CCN-TSN converged switching equipment as converged nodes at the network layer to execute preset forwarding logic; Control layer collaborative scheduling: Deploy the CCN-TSN centralized collaborative controller as the core management and control unit of the converged network, communicate with all converged nodes in real time, and realize time slot resource management, caching policy collaboration, and dynamic scheduling optimization.

[0011] Furthermore, the protocol layer extends the adaptation, including: 1) Extend CCN naming rules: Add TSN attribute fields to the original CCN content names. The TSN attribute fields include timestamp, traffic priority, latency constraint, TSN stream ID, and cache validity period. The traffic priority is divided into three levels according to the TSN standard: Class A, Class B, and Class C, which correspond to TSN hard real-time control flow, CCN real-time content flow, and ordinary content flow, respectively. 2) Modify the Interest / Data packet structure: Add a continuous subscription identifier, periodic request interval, and deadline field to the real-time Interest packet, and also carry a timestamp to achieve timing alignment with the TSN clock; add a TSN stream identifier and clock synchronization check code field to the Data packet to ensure the timing consistency of data transmission with the TSN scheduling window, and also carry a cache validity identifier to provide a decision basis for the cache management module. 3) Clock synchronization protocol compatibility: The IEEE 802.1AS protocol interface is integrated into the CCN protocol, enabling CCN nodes to access the TSN's full network clock synchronization system. It supports CCN nodes in responding to PTP clock drift / offset, keeping the clock synchronization accuracy between CCN and TSN within ±1μs.

[0012] Furthermore, the forwarding logic of the fusion node is as follows: After receiving the Interest / Data packet, parse the TSN attribute field and clock synchronization check code in the packet to verify timing consistency; Traffic is categorized based on priority fields to determine whether it is a TSN hard real-time control flow: if so, it directly enters the time slot queue and is forwarded according to the 802.1Qbv rule; if it is a CCN real-time content flow or a normal content flow, interest matching is performed; if the cache is hit, the data packet is returned directly and forwarded through the corresponding priority queue; if the cache is not hit, multi-path routing is performed, and the returned data packet is stored according to the caching policy.

[0013] Furthermore, control-layer coordinated scheduling includes: 1) Real-time flow admission control: The CCN-TSN centralized collaborative controller receives traffic access requests from terminals, verifies the latency, jitter, and bandwidth constraints of the traffic, allocates unique TSN flow IDs and time slot resources to qualified TSN hard real-time control flows and CCN real-time content flows, and rejects requests that exceed the network carrying capacity to avoid network congestion. 2) Cache strategy collaboration: The CCN-TSN centralized collaborative controller collects the TSN slot load, content popularity, and cache status of each fusion node in real time, and dynamically decides the cache location and validity period of the content. It deploys hot content cache on edge fusion nodes with low TSN slot load and reduces cache deployment on core nodes with high slot load to avoid cache resources occupying real-time stream slots. 3) Dynamic scheduling optimization: The CCN-TSN centralized collaborative controller monitors network traffic fluctuations and clock synchronization status in real time. When traffic bursts or clock drift occur, it automatically adjusts the TSN gating table and traffic priority mapping rules of the fusion node, and at the same time adjusts the CCN content routing strategy to ensure that the end-to-end latency of the hard real-time control flow is always controlled within the predetermined threshold, and the distribution efficiency of non-real-time content flow is no less than that of the pure CCN network.

[0014] The present invention also provides a CCN and TSN fusion system for implementing the above-mentioned CCN and TSN fusion method, including a terminal layer, a network layer and a control layer; The terminal layer includes a CCN request terminal and a CCN content terminal that support TSN, used to initiate content requests, provide content resources, and support the carrying and parsing of TSN attribute fields; The network layer includes at least one CCN-TSN converged switching device to realize protocol conversion, traffic scheduling, content caching and forwarding; The control layer includes a CCN-TSN centralized protocol controller, which communicates with the CCN-TSN fusion switching device to realize CNN real-time stream admission control, caching strategy coordination, and dynamic scheduling optimization.

[0015] Furthermore, the CCN-TSN converged switching device includes a TSN engine module, a CCN engine module, a protocol conversion module, a clock synchronization module, a traffic scheduling module, and a cache management module; The TSN engine module is used to implement the core deterministic scheduling function of TSN; The CCN engine module is used to implement the core content distribution function of CCN; The protocol conversion module is used to realize the bidirectional conversion between the modified CCN protocol and the TSN protocol. It parses the TSN attribute field in the Interest / Data packet, maps it to the scheduling parameters of the TSN stream, and feeds back the scheduling status of TSN to the CCN engine module. The clock synchronization module provides a global clock reference for the TSN engine module, CCN engine module, and traffic scheduling module, and performs clock alignment with other modules externally. The traffic scheduling module receives data streams from the protocol conversion module and performs global traffic scheduling. The cache management module is used to implement time-aware content caching strategies.

[0016] The beneficial effects of this invention are as follows: 1) This invention solves the clock synchronization incompatibility problem: By integrating a clock synchronization interface into the CCN protocol, it achieves full-network nanosecond-level clock synchronization between CCN and TSN with a synchronization accuracy of ±1μs, ensuring the timing consistency of content requests and data transmission in the converged network, and solving the problem that CCN traffic cannot be adapted to the TSN scheduling window in the prior art. 2) This invention achieves deep adaptation of the scheduling model: by modifying the naming rules and packet structure of the CCN protocol, designing a traffic scheduling module and priority mapping rules, CCN traffic is integrated into the time-slotted scheduling system of TSN. At the same time, the 802.1Qbu frame preemption mechanism is adopted to avoid the conflict between bursty CCN traffic and deterministic TSN scheduling, ensuring that the end-to-end latency of TSN Class A hard real-time control flow is ≤1ms and the jitter is ≤100μs. 3) This invention balances deterministic transmission and content distribution efficiency: Through a time-aware caching strategy, different caching schemes are adopted for different types of traffic, so that the converged network retains the hard real-time transmission capability of TSN and leverages the content distribution advantage of CCN. Compared with a pure TSN network, this invention utilizes the capabilities of TSN network to improve the bandwidth utilization of CCN non-real-time content streams and reduce end-to-end latency. 4) This invention enables the unified transmission of multiple types of traffic: Through unified priority mapping and isolation rules, it realizes the orderly transmission of TSN hard real-time control flow, CCN real-time content flow and CCN ordinary content flow, solves the problem of independent deployment of multiple networks in the prior art, and greatly reduces the network cabling and maintenance costs in scenarios such as industrial Internet and vehicle Internet. 5) This invention features dynamic adaptability and scalability: It achieves dynamic coordination of time slot scheduling and caching strategies through a centralized collaborative controller, which can adapt to network traffic fluctuations and clock state changes. At the same time, the protocol extension rules of this invention provide a foundation for standardization, which can flexibly adapt to the needs of different application scenarios and support seamless expansion of nodes. Attached Figure Description

[0017] Figure 1 This is a diagram of the overall architecture of the CCN-TSN converged network; Figure 2 This is a schematic diagram of the CCN-TSN converged switch structure; Figure 3 This is a flowchart of the method described in this invention; Figure 4 This is a flowchart illustrating the specific implementation of the method described in this invention. Detailed Implementation

[0018] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0019] This invention achieves deep integration of CCN and TSN through a three-layer technical architecture: protocol layer extension and adaptation, network layer converged node deployment, and control layer collaborative scheduling. At the same time, based on the CCN-TSN converged switch and centralized collaborative controller, time-aware caching and traffic scheduling strategies are formulated.

[0020] like Figure 1 As shown, the CCN and TSN fusion system of the present invention includes a terminal layer, a network layer and a control layer. The terminal layer includes a CCN request terminal and a CCN content terminal that support TSN, used to initiate content requests, provide content resources, and support the carrying and parsing of TSN attribute fields; wherein, the TSN chip is used to support TSN scheduling, and the CCN cache disk supports CCN data caching; The network layer includes at least one CCN-TSN converged switching device to realize protocol conversion, traffic scheduling, content caching and forwarding; The control layer includes a CCN-TSN centralized protocol controller, which communicates with the CCN-TSN converged switching equipment to realize real-time flow access control, caching strategy coordination, and dynamic scheduling optimization.

[0021] like Figure 2 As shown, the CCN-TSN converged switching device includes a TSN engine module, a CCN engine module, a protocol conversion module, a clock synchronization module, a traffic scheduling module, and a cache management module; The TSN engine module is used to implement the core deterministic scheduling functions of TSN, including 802.1Qbv time-aware shaping, 802.1Qch cyclic queuing and forwarding, and 802.1Qci single-stream filtering, reserving time slot resources for high-priority traffic and achieving microsecond-level jitter control. The CCN engine module is used to implement the core content distribution functions of CCN, including content routing, intra-network caching, Interest / Data packet matching, and implements time-aware caching strategies based on the cache management module. The protocol conversion module is used to realize the bidirectional conversion between the modified CCN protocol and the TSN protocol. It parses the TSN attribute field in the Interest / Data packet, maps it to the scheduling parameters of the TSN stream, and feeds back the scheduling status of TSN to the CCN engine module. The clock synchronization module, as the time base of the fusion node, is used to receive the PTP synchronization signal of the TSN master clock, providing a unified nanosecond-level time base for the TSN engine module, CCN engine module, and traffic scheduling module. At the same time, it sends synchronization signals to surrounding CCN nodes to achieve network-wide clock synchronization. The traffic scheduling module, as the core scheduling unit of the converged node, receives traffic parameters from the protocol conversion module and divides the traffic into three levels according to predefined priority rules: Hard real-time control flow (TSN Class A) > CCN real-time content flow (TSN Class B) > CCN ordinary content flow (TSN Class C). It adopts 802.1Qbv time slot scheduling and 802.1Qbu frame preemption mechanism to achieve isolated transmission of traffic with different priorities and avoid low-priority traffic blocking high-priority traffic. The cache management module implements a time-aware content caching strategy. Based on the cache validity flag of the data packet, traffic priority, and TSN time slot load, it decides the content, location, and validity period of the cache: no caching for TSN Class A hard real-time control streams, short-term caching (TTL≤5s) for CCN Class B real-time content streams, and hotspot caching + edge sinking for CCN Class C ordinary content streams.

[0022] like Figure 4 As shown, in the protocol extension and adaptation design of this system, relying on the underlying architecture of controller + SDK (Software Development Kit) + scheduling and forwarding module + CCN scheduling and storage module, the native CCN protocol is extended to TSN Ethernet convergence. According to the service transmission attributes, three types of CCN interest data streams—Class A, Class B, and Class C—are divided. Differentiated storage retrieval, queue mapping, and scheduling control logic are executed for each type of traffic. The data stream forwarding process is as follows: 1) Class A: TSN hard real-time control flow; This type of message is a unidirectional industrial control data stream, only sending CCN interest packets without corresponding CCN data response packets, and fully complies with the TSN time-sensitive network specification. After the data stream enters the scheduling and forwarding module, it directly bypasses the CCN scheduling and storage module (i.e., for Class A CCN interest packet traffic, the CCN's scheduling and storage capabilities are not used, and it is directly forwarded). No local cache lookup is performed, and it is uniformly mapped to scheduling queue 0 and queue 1 (TSN dedicated scheduling queues). Relying on the time slot opening scheduling mechanism of 802.1Qbv gating management, the message transmission is constrained at the link timing level to ensure low latency and low jitter transmission indicators for industrial control messages. 2) Class B: CCN real-time content data stream; This type of message belongs to a bidirectional request-response business flow, consisting of a CCN interest request message and a corresponding CCN Data reply message. After the interest request message arrives at the scheduling and forwarding module, it is first sent to the CCN scheduling and storage module to retrieve local cached resources. When the target data is hit in the local cache: the data is directly extracted from the cache, encapsulated into a CCN Data message, and responded upwards without dequeueing or forwarding. If no matching content is found in the local cache: the scheduling and forwarding module maps the interest stream to scheduling queue 2 and queue 3 (the dedicated TSN queue for real-time content), and completes TSN time-series scheduling and external network forwarding based on the corresponding gating management.

[0023] 3) Class C: Ordinary CCN business data stream; These messages are non-real-time routine business data and do not require the reliance on the TSN time-sensitive scheduling link. After receiving the message, the scheduling and forwarding module directly schedules it to scheduling queue 7, and the corresponding priority management module completes the general queue queuing and message scheduling.

[0024] The TSN uses eight priority queues (TC0-TC7, queue numbers 0-7) defined by the IEEE 802.1Q standard, each corresponding to a PCP (Priority Code Point) field in the VLAN tag. Priorities increase sequentially from 0 to 7. These queues form the basis for TSN's traffic classification, scheduling, and deterministic transmission, providing differentiated services through mechanisms such as 802.1Qbv Time-Aware Scheduling (TAS) and 802.1Qav Credit Shaping (CBS). These queues are used during CCN forwarding to map data streams from different CCNs to different priority queues.

[0025] like Figure 3 As shown, the present invention provides a method for fusing CCN and TSN, comprising: Protocol layer extension and adaptation: The CCN protocol is extended to adapt to the underlying TSN protocol, enabling the construction of CCN interest data streams; Network layer converged node deployment: CCN-TSN converged switching equipment is deployed at the network layer as converged nodes to execute preset forwarding logic; including a scheduling and forwarding module and a CCN scheduling and storage module; Control layer collaborative scheduling: Deploy the CCN-TSN centralized collaborative controller as the core management and control unit of the converged network, communicate with all converged nodes in real time, and realize time slot resource management, caching policy collaboration, and dynamic scheduling optimization.

[0026] Protocol layer extension adaptation includes:

[0027] 1) Extend CCN naming rules: Add a TSN attribute field to the existing CCN content name. The TSN attribute field includes timestamp, traffic priority, latency constraint, TSN stream ID, and cache expiration period. Example: / factory / line1 / sensor / temp / tsn_prio=1 / timestamp / tsn_id=001 / cache_ttl, or / factory / line1 / sensor / temp / tsn_prio=4 / timestamp / tsn_id=002 / cache_ttl, or / factory / line1 / sensor / temp / tsn_prio=7 / timestamp / tsn_id=003 / cache_ttl, for... Figure 4 The CCN interest data stream in the TSN is divided into three levels of traffic priority according to the TSN standard: Class A, Class B, and Class C, which correspond to hard real-time control stream, real-time content stream, and normal content stream, respectively. Based on the above naming extension rules, TSN can perform priority scheduling based on the stream ID during scheduling.

[0028] 2) Modify the Interest / Data packet structure: Add continuous subscription identifier, periodic request interval, and deadline fields to the real-time Interest packet to adapt to the periodic stream scheduling requirements of TSN; it also carries a timestamp to achieve time alignment with the TSN clock; the Interest packet is a packet type in CCN called "Interest Packet"; the message contains a request header in URL format, that is, adding identifier, request interval, and other fields to the URL format, so that when TSN schedules messages according to the clock, it can prioritize and schedule forwarding according to these fields; Data packet: add TSN stream identifier and clock synchronization check code fields to ensure the time consistency of data transmission with the TSN scheduling window, and carry a cache validity identifier to provide a decision basis for the cache management module.

[0029] Specifically, timing alignment to achieve synchronization with the TSN clock includes: The timestamp added by the node refers to the timestamp obtained in the Interest message sent after running the gPTP protocol to synchronize the TSN clock across the entire network. This ensures that the global timestamps are consistent. This includes: Message-level timestamps carry: When the terminal generates an Interest request message and the forwarding node processes a Data response message, a high-precision timestamp generated by the unified gPTP clock across the entire network is embedded as a timing reference identifier. Request timing constraint binding: Configure the periodic request interval and deadline fields in the real-time Interest message to bind the CCN content request period with the TSN scheduling time slot period, ensuring that the request message is sent strictly according to the TSN time slot beat; Transmission timing verification: The fusion node parses the timestamp and clock synchronization check code in the message, compares it with the local nanosecond-level clock reference, and discards or reschedules messages that exceed the timing deviation threshold to prevent out-of-order transmission. Scheduling window matching: Based on the TSN attribute field of the packet, the traffic scheduling module accurately maps the corresponding traffic to the TSN802.1Qbv preset scheduling window, so that the sending, receiving and forwarding actions of CCN packets are completely in line with the TSN time slot scheduling rhythm, and finally realizes the full-domain timing alignment of CCN service flow with the TSN deterministic scheduling system.

[0030] During the message reception phase, the fusion node prioritizes timing validity verification. Only messages with valid timing alignment can enter the subsequent queue scheduling and forwarding process. High-priority hard real-time control flow is directly bound to a dedicated time slot queue and is transmitted in strict accordance with TSN timing rules. The CCN real-time / normal content flow, combined with the cache hit status, completes message acknowledgment and forwarding within the corresponding priority time slot window, maintaining timing synchronization throughout the process and avoiding disruption of TSN scheduling order due to out-of-order forwarding.

[0031] 3) Clock synchronization protocol compatibility: The IEEE 802.1AS protocol interface is integrated into the CCN protocol, enabling CCN nodes to access the TSN's full network clock synchronization system. It supports CCN nodes in responding to PTP clock drift / offset, keeping the clock synchronization accuracy between CCN and TSN within ±1μs.

[0032] CCN uses TSN's gPTP protocol, which uses hardware timestamps for global clock synchronization, achieving microsecond-level clock accuracy. CCN uses the synchronized time data, thus achieving microsecond-level clock accuracy. The gPTP clock synchronization process is as follows: Hardware timestamp collection: All CCN terminals and CCN-TSN converged switching equipment are equipped with gPTP hardware clock units. The hardware directly marks the timestamps of packets at the moment of transmission and reception at the physical layer interface, which is different from the software timestamps at the operating system kernel layer. This avoids millisecond-level latency jitter caused by system scheduling and protocol stack processing, and reduces time errors from the bottom layer. gPTP master-slave clock architecture: A unique TSN master clock node is deployed in the network as the global time reference, and all other CCN nodes, converged nodes and terminals in the network are slave clocks; the master clock periodically publishes gPTP synchronization messages to the outside world, and the slave nodes receive the messages, parse the hardware timestamp, and calculate the link transmission delay and local clock offset. Clock skew and delay compensation: The slave node automatically completes the one-way delay calculation of the link and the local clock drift compensation based on the master clock time carried in the synchronization message and the hardware timestamp of the message entry and exit port. It corrects the local clock frequency and phase in real time so that the local clock continuously follows the global master clock. CCN protocol stack clock reuse: The CCN protocol stack directly calls the local high-precision clock data after synchronization is completed. The timestamp and timing constraint fields in the message are all taken from the unified clock after gPTP calibration. At the same time, the CCN protocol integrates the gPTP protocol interface, and the node can actively respond to clock drift and frequency offset events to trigger secondary fast calibration.

[0033] Deployment method for converged nodes: Forwarding is performed through a CCN-TSN converged switch / router that integrates six major functional modules; the forwarding logic of the converged node is as follows: 1) After receiving the Interest / Data packet, parse the TSN attribute field and clock synchronization check code in the packet to verify timing consistency; 2) Traffic is classified according to the priority field to determine whether it is a TSN hard real-time control flow: If so, it directly enters the time slot queue of the TSN engine module and is forwarded according to the 802.1Qbv rule without going through the cache processing of the CCN engine module; if it is a CCN real-time content stream or a normal content stream, it enters the CCN engine module for interest matching: if the cache is hit, the cache management module directly returns a data packet, which is forwarded through the corresponding priority queue of the traffic scheduling module; if the cache is not hit, the CCN engine module performs multi-path routing and forwarding, and at the same time stores the returned data packet according to the CNN caching strategy.

[0034] Multi-path routing refers to a cache miss, indicating that there is no data on the local disk and data needs to be found. It involves searching for data via multiple paths, which can achieve load balancing or forwarding according to the optimal route in the standard CNN.

[0035] The CNN caching strategy is as follows: hard real-time control streams are not cached, real-time content streams are cached for short periods, and ordinary content streams use hotspot-based caching. After the fusion node completes packet timing and priority verification, it executes cache-linked forwarding logic for non-Class A traffic: when an interest request matches a valid local cache, it directly retrieves the cached data packet to respond to the request, without routing to upstream nodes; if the cache misses, it performs multi-path routing forwarding. After the upstream returns a data packet, the cache management module combines the current node's TSN slot load, traffic type, and cache validity flag to determine whether to cache and set the corresponding TTL. After completing local data storage, it forwards the data downwards. All cache read / write operations are designed to avoid conflict with the TSN Class A dedicated scheduling slots, ensuring that hard real-time stream transmission is not affected by caching services.

[0036] Control layer collaborative scheduling: Deploy the CCN-TSN centralized collaborative controller as the core management and control unit of the converged network, communicate with all converged nodes in real time, and realize time slot resource management, caching policy collaboration, and dynamic scheduling optimization; 1) Real-time flow admission control: The CCN-TSN centralized collaborative controller receives traffic access requests from terminals, verifies the latency, jitter, and bandwidth constraints of the traffic, allocates unique TSN flow IDs and time slot resources to qualified TSN hard real-time control flows and CCN real-time content flows, and rejects requests that exceed the network carrying capacity to avoid network congestion. 2) Caching Strategy Collaboration: The CCN-TSN centralized collaborative controller collects real-time data on TSN slot load, content popularity, and cache status from each fusion node. It dynamically determines the cache location and expiration time of content, deploying cached hot content on edge fusion nodes with low TSN slot load and reducing cache deployment on core nodes with high slot load to avoid caching resources consuming real-time streaming slots. Specifically, this includes: a) The CCN-TSN centralized collaborative controller collects information such as TSN timeslot load, content popularity, and cache status of each converged node in real time through standard network management interface protocols. The device nodes support standard collection protocols such as netconf, syslog, and snmp. Among them, timeslot load mainly tests the load capacity of the device nodes. For nodes that forward a large amount of data from the device, the device needs to use a large amount of its capacity for forwarding data. The controller will notify the CCN node to minimize the data caching of the node. Content popularity is the hot spot information of CCN's data. This information is derived by comparing the number of times data is collected from multiple devices. Cache status is the CCN cached data. b) For busy nodes, frequent caching of data can affect forwarding. Therefore, the controller coordinates caching strategies: for idle nodes with fewer data requests, the controller caches return data to the node as much as possible by changing routes; for busy nodes, the controller uses limited resources for forwarding by reducing caching or aging caching.

[0037] 3) Dynamic scheduling optimization: The CCN-TSN centralized collaborative controller monitors network traffic fluctuations and clock synchronization status in real time. When traffic bursts or clock drift occur, it automatically adjusts the TSN gating table and traffic priority mapping rules of the fusion node, and adjusts the CCN content routing strategy at the same time to ensure that the end-to-end latency of the hard real-time control flow is always controlled within the predetermined threshold, and the distribution efficiency of non-real-time content flow is no less than that of the pure CCN network.

[0038] Specifically, the CCN introduces a TSN scheduling mechanism. The CCN-TSN centralized collaborative controller monitors network traffic fluctuations and clock synchronization status in real time. When a traffic surge occurs, the TSN's gating list mechanism ensures efficient data distribution. For example, if traffic A is initially at 1 Mbit / s, the gating switch is open for 1 ms, opening once every 500 ms, allowing only traffic A to pass during this time. If traffic A suddenly increases to 2 Mbit / s, the 1 ms opening duration is insufficient for 2 Mbit / s traffic, and the gating opening duration no longer meets the requirements. Therefore, the controller needs to detect this change in real time and adjust the A gating opening time to 2 ms. This modification will reduce the throughput of other traffic types; this is the modification threshold for hard real-time streams.

[0039] For non-real-time content streams, forwarding relies on the TSN's medium-priority queue. After high-priority hard real-time streams are forwarded, medium-priority non-real-time streams are forwarded through a queue gating list. Compared to the best-effort forwarding of traditional CCN networks, this design caches and queues data in order, achieving low-jitter forwarding of hard real-time streams while maintaining data distribution efficiency no lower than that of a pure CCN network.

[0040] In summary, the control layer collaborative scheduling is primarily responsible for collecting data information from the entire CCN-TSN network, including interface bandwidth, usage, and CCN cache status. Based on this data, the entire real-time flow admission control system is constructed. For an incoming data flow, after receiving the flow request, the CCN-TSN centralized collaborative controller reserves bandwidth and timing for all devices across the network based on the flow's TSN latency, jitter, and bandwidth requirements. If any device in the network cannot meet the requirements, the flow's access request will be rejected. This is real-time flow admission control, which differs fundamentally from traditional CCN access, which lacks admission control and does not impose constraints such as latency. For data flows that meet the admission requirements, a globally assigned flow ID is distributed to all network devices. For subsequent CCN data flows, such as interest packets, which contain the flow ID keyword, the global devices schedule and forward them based on the ID.

[0041] Content popularity is a core metric for measuring the frequency and importance of content requests, determining caching strategies and resource allocation. The calculation formula is: P_full = (Basic Interaction Score × Quality Coefficient) × Time Decay Coefficient + Initial Popularity; CCN cache location decisions are based on two dimensions: content popularity and node importance. The PBCS (Popularity and Betweenness based Caching Scheme) algorithm is commonly used.

[0042] The cache status mainly includes indicators such as the remaining cache capacity. If the capacity is too small, it cannot be cached.

[0043] Time slot load is a dimensional metric of TSN; if the load is too heavy, caching should be reduced or eliminated.

[0044] Coordination of caching strategies includes: Calculate the overall cache value score by multiplying the popularity weight by the normalized content popularity, subtracting the time slot load weight multiplied by the network transmission cost calculated based on the time slot average load index, and then subtracting the cache status weight multiplied by the cache replacement cost calculated by combining the node cache occupancy rate and the content cache duration. Calculate the dynamic cache admission threshold: multiply the base fixed threshold by the natural exponent based on the average load per time slot and the threshold adjustment coefficient; Final cache determination: If the overall cache value score is greater than the dynamic admission threshold, the current node caches the content; if it is less than or equal to the threshold, the node does not cache the content, and the cached content is evicted.

[0045] Taking the intelligent manufacturing scenario of the industrial internet as an example, the implementation process of this invention is illustrated, and the required equipment, parameters, and steps are as follows: (a) Implementation equipment: CCN-TSN converged switches (3 units, deployed at the edge / core of the production workshop), PLC control terminals (TSN Class A terminals, 2 units), equipment status monitoring terminals (CCN Class B terminals, 5 units), video surveillance terminals (CCN Class C terminals, 3 units), CCN-TSN centralized collaborative controller (1 unit), industrial server (1 unit, serving as the TSN master clock and CCN content source); (II) Core Parameters: 1) Clock synchronization accuracy: ±30ns (based on gPTP clock synchronization scheme); 2) TSN Class A stream latency threshold: ≤1ms, jitter threshold: ≤100μs; 3) CCN Class B stream cache TTL: 5s, CCN Class C stream hot content cache TTL: 3600s; 4) Time slot allocation: Each scheduling cycle is 10ms, of which 8ms are allocated to TSN Class A streams and 2ms are allocated to CCN Class B / C streams; (III) Implementation steps: Step 1: Deploy all hardware devices, connect the converged switch, terminals, controllers, and industrial servers via Gigabit Ethernet, configure the industrial server as the TSN master clock and CCN content source, and send out the initial PTP synchronization signal; Step 2: Configure traffic priority rules and caching strategies in the collaborative controller, and define TSN Class A as PLC motion control flow, CCN Class B as device status sensor data flow, and CCN Class C as video monitoring flow; Step 3: The clock synchronization module of each converged node receives the generalized precision time protocol (gPTP) synchronization signal to achieve network-wide clock synchronization. The coordinating controller allocates TSN stream IDs and time slot resources to the traffic of each terminal. Step 4: The PLC control terminal sends a TSN Class A Interest hard real-time control flow, which is converted by the protocol conversion module and then forwarded in time slots through the TSN engine module of the converged switch to achieve microsecond-level deterministic transmission. Step 5: The device status monitoring terminal sends a CCN Class B Interest packet. The CCN engine module of the converged switch matches the local short-term cache. If a match is found, a Data packet is returned directly. If a match is not found, the packet is routed to the industrial server. At the same time, the returned Data packet is cached for 5 seconds. Step 6: The video surveillance terminal sends a CCN Class C Interest packet. The CCN engine module of the converged switch matches the hotspot cache of the edge node to achieve local acquisition, which greatly reduces end-to-end latency. Step 7: The collaborative controller monitors the network load in real time. When video surveillance traffic suddenly increases, it automatically adjusts the time slot allocation ratio (e.g., 7ms for TSN Class A stream and 3ms for CCN stream) and adjusts the CCN content routing strategy to avoid preempting hard real-time stream resources. Step 8: When PTP clock drift occurs, the clock synchronization module automatically calibrates, and the co-controller adjusts the scheduling window of the fusion node to ensure the timing consistency of all traffic.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to further limit the present invention. All equivalent changes made based on the description and drawings of the present invention are within the protection scope of the present invention.

Claims

1. A method for fusing CCN and TSN, characterized in that, include: Protocol layer extension and adaptation: The CCN protocol is extended to achieve underlying adaptation with the TSN protocol; Network layer converged node deployment: Deploy CCN-TSN converged switching equipment as converged nodes at the network layer to execute preset forwarding logic; Control layer collaborative scheduling: Deploy the CCN-TSN centralized collaborative controller as the core management and control unit of the converged network, communicate with all converged nodes in real time, and realize time slot resource management, caching policy collaboration, and dynamic scheduling optimization.

2. The method for fusing CCN and TSN according to claim 1, characterized in that, Protocol layer extension adaptations include: 1) Extend CCN naming rules: Add TSN attribute fields to the original CCN content names. The TSN attribute fields include timestamp, traffic priority, latency constraint, TSN stream ID, and cache validity period. The traffic priority is divided into three levels according to the TSN standard: Class A, Class B, and Class C, which correspond to TSN hard real-time control flow, CCN real-time content flow, and ordinary content flow, respectively. 2) Modify the Interest / Data packet structure: Add a continuous subscription identifier, periodic request interval, and deadline field to the real-time Interest packet, and also carry a timestamp to achieve timing alignment with the TSN clock; add a TSN stream identifier and clock synchronization check code field to the Data packet to ensure the timing consistency of data transmission with the TSN scheduling window, and also carry a cache validity identifier to provide a decision basis for the cache management module. 3) Clock synchronization protocol compatibility: The IEEE 802.1AS protocol interface is integrated into the CCN protocol, enabling CCN nodes to access the TSN's full network clock synchronization system and supporting CCN nodes to respond to PTP clock drift / offset.

3. The method for fusing CCN and TSN according to claim 1, characterized in that, The forwarding logic of the fusion node is as follows: After receiving the Interest / Data packet, parse the TSN attribute field and clock synchronization check code in the packet to verify timing consistency; Traffic is categorized based on priority fields to determine whether it is a TSN hard real-time control flow: if so, it directly enters the time slot queue and is forwarded according to the 802.1Qbv rule; if it is a CCN real-time content flow or a normal content flow, interest matching is performed; if the cache is hit, the data packet is returned directly and forwarded through the corresponding priority queue; if the cache is not hit, multi-path routing is performed, and the returned data packet is stored according to the caching policy.

4. The method for fusing CCN and TSN according to claim 1, characterized in that, Control layer coordinated scheduling, including: 1) Real-time flow admission control: The CCN-TSN centralized collaborative controller receives traffic access requests from terminals, verifies the latency, jitter, and bandwidth constraints of the traffic, allocates unique TSN flow IDs and time slot resources to qualified TSN hard real-time control flows and CCN real-time content flows, and rejects requests that exceed the network's carrying capacity. 2) Cache strategy collaboration: The CCN-TSN centralized collaborative controller collects the TSN slot load, content popularity, and cache status of each fusion node in real time, and dynamically decides the cache location and validity period of the content. It deploys hot content cache on edge fusion nodes with low TSN slot load and reduces cache deployment on core nodes with high slot load. 3) Dynamic scheduling optimization: The CCN-TSN centralized collaborative controller monitors network traffic fluctuations and clock synchronization status in real time. When traffic bursts or clock drift occur, it automatically adjusts the TSN gating table and traffic priority mapping rules of the fusion node, and at the same time adjusts the CCN content routing strategy to ensure that the end-to-end latency of the TSN hard real-time control flow is always controlled within the predetermined threshold, and the distribution efficiency of non-real-time content flow is no less than that of the pure CCN network.

5. A fusion system of CCN and TSN, characterized in that, A method for implementing the fusion of CCN and TSN as described in any one of claims 1-4, comprising a terminal layer, a network layer, and a control layer; The terminal layer includes a CCN request terminal and a CCN content terminal that support TSN, used to initiate content requests, provide content resources, and support the carrying and parsing of TSN attribute fields; The network layer includes at least one CCN-TSN converged switching device to realize protocol conversion, traffic scheduling, content caching and forwarding; The control layer includes a CCN-TSN centralized protocol controller, which communicates with the CCN-TSN converged switching equipment to realize real-time CCN flow admission control, caching strategy coordination, and dynamic scheduling optimization.

6. The CCN and TSN fusion system according to claim 5, characterized in that, The CCN-TSN converged switching equipment includes a TSN engine module, a CCN engine module, a protocol conversion module, a clock synchronization module, a traffic scheduling module, and a cache management module. The TSN engine module is used to implement the core deterministic scheduling function of TSN; The CCN engine module is used to implement the core content distribution function of CCN; The protocol conversion module is used to realize the bidirectional conversion between the modified CCN protocol and the TSN protocol. It parses the TSN attribute field in the Interest / Data packet, maps it to the scheduling parameters of the TSN stream, and feeds back the scheduling status of TSN to the CCN engine module. The clock synchronization module provides a global clock reference for the TSN engine module, CCN engine module, and traffic scheduling module, and performs clock alignment with other modules externally. The traffic scheduling module receives data streams from the protocol conversion module and performs global traffic scheduling. The cache management module is used to implement time-aware content caching strategies.

Images