Elastic satellite optical network service slice transmission method

Abstract

The invention relates to the technical field of telecommunication, in particular to an elastic satellite optical network service slice transmission method, which comprises the following steps of: mapping a customer service to an OPU frame payload area, and adding mapping overhead to an OPU overhead area to form an OISL-OPU frame; on the basis of the OISL-OPU frame, ODU overhead is added to provide a channel monitoring function, and an OISL-ODU frame is formed; the OTU overhead is added based on the OISL-ODU frame, and an OISL-OTU frame is formed; fEC is added to an OISL-OTU frame, forward error correction is completed by synchronously mapping to an FEC frame, and finally, a formed OISL physical layer interface signal is converted into an optical signal to be sent. Compared with the OISL-MPLS, by adopting a flexible time slot multiplexing mode and the like, the time delay of a single node is greatly reduced, and when the frame length is 68B-1522B, the time delay is respectively reduced by 44.72%-58.58%; according to the method and the system, packet jitter is remarkably reduced, the reduction amplitude is 26.67%-75.00%, the problem that time delay and jitter are uncertain is effectively solved, space-based time delay sensitive type service requirements are met, and therefore the problem that a satellite optical network constructed based on OISL-MPLS cannot meet pipeline isolation is solved.

Description

Technical Field

[0001] The present invention relates to the field of electrical communication technology, and in particular to a method for transmitting elastic satellite optical network service slices. Background Art

[0002] The transparent forwarding and high mobility characteristics of low-orbit satellite internet make it difficult to ensure stable service quality using traditional network models, seriously hindering the application and development of space-based, latency-sensitive services. By implementing a resilient intersatellite optical pipeline (OISL-OSU) based on the Optical Service Unit (OSU), a deterministic satellite optical network is constructed to provide hard-pipe isolation, guarantee transmission latency and jitter, and improve service stability.

[0003] Satellite optical networks built on Open Interconnect Multi-Protocol Label Packet Switching (OISL-MPLS) technology cannot meet the requirements of pipeline isolation and latency and jitter uncertainty. Therefore, this paper proposes a resilient satellite optical network transmission method based on OISL-OSU, providing deterministic services with bandwidth, latency, reliability, and security isolation for high-value scenarios. Summary of the Invention

[0004] The purpose of the present invention is to provide a flexible satellite optical network service slicing transmission method, which aims to solve the problem that the satellite optical network built based on OISL-MPLS cannot meet pipeline isolation.

[0005] To achieve the above objectives, the present invention provides a method for transmitting elastic satellite optical network service slices, comprising the following steps:

[0006] Map the customer service to the payload area of ​​the OPU frame, and add the mapped overhead to the OPU overhead area to form an OISL-OPU frame;

[0007] Based on the OISL-OPU frame, the ODU overhead is added to provide the channel monitoring function to form the OISL-ODU frame;

[0008] Add OTU overhead based on the OISL-ODU frame to form an OISL-OTU frame;

[0009] FEC is added to the OISL-OTU frame, and forward error correction is performed by synchronously mapping it to the FEC frame. Finally, the resulting OISL physical layer interface signal is converted into an optical signal for transmission.

[0010] Among them, in "mapping the customer service to the OPU frame payload area, and mapping the overhead to the OPU overhead area to form an OISL-OPU frame", the OISL-OPU frame has a 4-row 3810-column structure, consisting of OPU overhead and OPU payload.

[0011] Among them, in “Based on the OISL-OPU frame, the ODU overhead is added to provide a channel monitoring function to form the OISL-ODU frame”, the OISL-OPU frame has a 4-row 3824-column structure, and is composed of the ODU overhead and the OISL-OPU frame.

[0012] Among them, in “adding OTU overhead based on OISL-ODU frame to form OISL-OTU frame”, the OISL-OTU frame adopts a fixed-length frame structure, which consists of an OTU overhead area and an OTU payload area.

[0013] Among them, in "adding FEC to the OISL-OTU frame, completing forward error correction by synchronously mapping it to the FEC frame, and finally converting the formed OISL physical layer interface signal into an optical signal for transmission", the OISL physical layer interface includes the universal OISL-OTU frame, OISL-ODU frame, OISL-OPU frame and the interface-specific OISL-OTU-FEC frame.

[0014] The present invention provides a flexible satellite optical network service slicing transmission method, comprising the following steps: mapping customer services to an OPU frame payload area, and mapping overhead to be added to the OPU overhead area to form an OISL-OPU frame; based on the OISL-OPU frame, adding an ODU overhead to provide a channel monitoring function to form an OISL-ODU frame; based on the OISL-ODU frame, adding an OTU overhead to form an OISL-OTU frame; adding FEC to the OISL-OTU frame, completing forward error correction by synchronously mapping it to the FEC frame, and finally converting the formed OISL physical layer interface signal into an optical signal for transmission. Compared with OISL-MPLS, the present invention significantly reduces single-node delay by adopting flexible time slot multiplexing, and when the frame length is 68B to 1522B, the delay is reduced by 44.72%-58.58% respectively; packet jitter is also significantly reduced, with a reduction range of 26.67%-75.00%, effectively solving the uncertainty of delay and jitter problems, meeting the needs of space-based delay-sensitive services, and thus solving the problem that satellite optical networks built based on OISL-MPLS cannot meet pipeline isolation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 This is a diagram showing the relationship between OISL physical layer interface information.

[0017] Figure 2 Figure 1 is the OISL-OSU frame structure diagram; (a) is the OISL-OTU-FEC frame structure and (b) is the OISL-OPU frame structure based on OSU.

[0018] Figure 3 This is a schematic diagram of 16-row RS encoding.

[0019] Figure 4 Figure 1. Comparison between the CCSDS AOS standard frame and the OISL-MPLS extended frame. (a) shows the CCSDS AOS standard frame structure, and (b) shows the CCSDS AOS extended frame structure.

[0020] Figure 5 This is the throughput comparison test result.

[0021] Figure 6 It is the round-trip delay (RTD) comparison test result.

[0022] Figure 7 This is the jitter comparison test result.

[0023] Figure 8 This is a back-to-back comparison test result.

[0024] Figure 9 This is a flowchart of a flexible satellite optical network service slicing transmission method provided by the present invention. DETAILED DESCRIPTION

[0025] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0026] See also Figures 1 to 9 The present invention provides a method for transmitting elastic satellite optical network service slices, comprising the following steps:

[0027] S1 maps the customer service into the payload area of ​​the OPU frame and adds the mapped overhead to the OPU overhead area to form an OISL-OPU frame;

[0028] The OISL-OPU frame has a 4-row 3810-column structure and consists of an OPU overhead and an OPU payload.

[0029] Specifically, the OISL-OPU frame has a 4-row, 3810-column structure and consists of two parts: OPU overhead and OPU payload. Columns 15 to 16 of the OPU carry the OPU overhead, while columns 17 to 3824 carry the OPU payload.

[0030] S2 is based on the OISL-OPU frame and adds ODU overhead to provide channel monitoring function to form the OISL-ODU frame;

[0031] The OISL-OPU frame has a 4-row 3824-column structure and consists of an ODU overhead and an OISL-OPU frame.

[0032] Specifically, the OISL-ODU frame has a 4-row, 3824-column structure and consists primarily of two parts: the ODU overhead and the OISL-OPU frame. Columns 1 through 14 are the ODU overhead, but columns 1 through 14 of row 1 are used to carry the frame alignment signal and OTU overhead. Columns 1 through 14 of rows 2, 3, and 4 carry the ODU overhead. Columns 15 through 3824 carry the OISL-OPU frame.

[0033] S3 adds OTU overhead based on the OISL-ODU frame to form an OISL-OTU frame;

[0034] The OISL-OTU frame adopts a fixed-length frame structure, consisting of an OTU overhead area and an OTU payload area.

[0035] Specifically, the OISL-OTU frame uses a fixed-length frame structure and consists of two main parts: the OTU overhead area and the OTU payload area. Columns 1 to 14 of row 1 are the OTU overhead, columns 1 to 14 of rows 2 to 4 are the ODU overhead, and columns 15 to 3824 of rows 1 to 4 are the OTU payload. Each column represents a byte column.

[0036] S4 adds FEC to the OISL-OTU frame, performs forward error correction by synchronously mapping it to the FEC frame, and finally converts the resulting OISL physical layer interface signal into an optical signal for transmission.

[0037] The OISL physical layer interface includes a universal OISL-OTU frame, an OISL-ODU frame, an OISL-OPU frame and an interface-oriented specific OISL-OTU-FEC frame.

[0038] Specifically, the OISL physical layer interface includes universal OISL-OTU frames, OISL-ODU frames and OISL-OPU frames as well as interface-specific OISL-OTU-FEC frames, such as Figure 2 As shown in (a).

[0039] OISL-OTU-FEC frame: used to adapt FEC coding, which is related to the specific interface. Different interfaces can use different FEC. The present invention shows an FEC frame structure based on RS (255, 223) coding, which mainly consists of three parts: FEC overhead, FEC payload area, and FEC check area. Columns 1 to 32 of the first row are FEC overhead, columns 33 to 3488 of the first row and columns 1 to 3488 of rows 2-5 are FEC payload areas, which are used to carry adapted OISL-OTU frame signals (OISL-OTU frames are synchronously mapped to the FEC frame payload area). Columns 3489 to 4000 of rows 1-5 are FEC check areas.

[0040] OISL-OSU service slicing technology achieves flexible service slicing adaptation and cross-connection through OSU (approximately 2.6 Mbps) mapping and multiplexing. Based on an extension of ITU-T G.709 technology, the OSU abstracts a container layer on the OISL-OPU payload, enabling the transport of various fixed-rate (CBR) and variable-rate (VBR) services. This provides hard isolation, high security, low latency, and flexible bandwidth transmission for onboard services. By mapping / multiplexing the OSU into the OPU payload, OSU / ODU layer adaptation is achieved, enabling transmission of OSU services to the line side. The number of OSU links supported by each ODU is affected by factors such as the P value, the tributary port number (TPN) length, and the number of ODU multiplexing levels. The OSU carries services with fewer mapping layers, achieving single-point latency with jitter down to microseconds, enabling deterministic low latency. Each OPU has a 192-byte PB size, and the OPU payload is divided into multiple PBs starting from row 1, column 17 of an OPU frame. One PB spans two consecutive OPU frames. Figure 2 (b) illustrates an example of dividing the OPU payload into multiple consecutive PBs. This new multiplexing structure differs from the traditional tributary timeslot structure. It also requires the definition of a new payload type value, such as 0x23 for PT overhead.

[0041] The implementation process of RS coding interleaving is shown in the figure. During the FEC processing, one row of data in the OISL-OTU-FEC frame is divided into 16 sub-rows in a byte interleaving manner, and each FEC codec processes one sub-row. The sending order of the OISL-OUT-FEC frame bytes after filling the RS interleaving coding is as follows: Figure 3 shown.

[0042] The frame structure of the ODU is decomposed to form multiple payload blocks (PBs), and each OSU occupies one or more PB pairs. The introduction of the flexible mapping OSU allows for flexible setting of the PB broadband. The OSU can support the minimum granularity design of customer services through the PB broadband, and has the efficient carrying capacity for multiple services with a granularity of 10Mbps to 10Gbps based on the OSU bearer container. The OSU bit rate is related to the type of packet service (PKT) being transmitted. The client signal is first mapped to the OSU and then multiplexed into the OPU frame through the optical service tributary unit (OSTU) structure. The OSTU structure consists of C PB blocks in the transmission cycle of P consecutive OPU PB blocks. The maximum C value (in PB blocks) determines the maximum OSU bit rate for each specific client service. The maximum C value is calculated as follows

[0043]

[0044] where R client 、R client_tolerance 、R PB and R PB_tolerance They represent client bit rate, client bit rate tolerance, OSU PB reference bit rate and OSU PB reference bit rate tolerance (±20ppm) respectively. The OSU maximum bit rate is calculated as follows

[0045] R OSU =C×R PB (2)

[0046] The maximum payload bit rate of OSU is calculated as follows:

[0047]

[0048] For packet services (PKT) carried by OSU, the main application requirement is MAC transparent transmission. The maximum bit rate of PKT only needs to consider the nominal Ethernet MAC bit rate, which is the maximum guaranteed bandwidth that OSU can provide for PKT. OSU is suitable for carrying Ethernet services with no fixed bit rate. The bit rate of OSU will change with the change of service traffic. The specific range of change is PB base bit rate (R PB ) 4 to C times. C×R PB is the maximum OSU bit rate, where C corresponds to the maximum guaranteed bandwidth provided by the OSU connection for Ethernet services. Table 1 illustrates the calculation of the maximum OSU bit rate for typical Ethernet services.

[0049] Table 1 OSU bit rates at different Ethernet service rates

[0050]

[0051] Note: 1.R OSU =C×R PB ,R PB =2.6Mbps;

[0052] 2. R PB =2.6Mbps.

[0053] Table 2 lists the bandwidth of 2.6Mbps as the OSU PB benchmark (R PB ) conditions, the P values ​​corresponding to different ODU rates, the actual PB bit rates of different OPUk are close to the OSU PB reference bandwidth, and the P values ​​are as follows

[0054]

[0055] Table 2 P value and PB value corresponding to different OPUk

[0056]

[0057] OISL-MPLS packet switching is based on AOS standard frames (such as Figure 4 (a) shows) that a piece of the transmission frame insertion domain is divided into an extended control field to realize label-based AOS frame forwarding and the carrying of various types of services. The extended control field consists of the label field (Label) and the data communication network field (DCN), as shown in Figure 1. Figure 4 (b) As shown. By using the label field, label switching-based AOS frame forwarding is implemented on the label switching node (LSR) to replace IP address-based routing forwarding, avoiding unnecessary data frame splitting-comparison-reframe process. OISL-MPLS supports multiple types of service transmission, and different types of services are placed in the transfer frame data field of the AOS frame for transmission, such as Figure 4 The technical comparison between OISL-OSU and OISL-MPLS designed by the present invention is shown in Table 3.

[0058] Table 3 Comparison of OISL-OSU and OISL-MPLS technologies

[0059]

[0060] To illustrate the improvement effect of the OISL-OSU designed in this invention, the performance of OISL-OSU and OISL-MPLS was compared based on the RFC 2544 standard. Under the condition of 0% packet loss rate, the test results of throughput, round trip delay, packet jitter and back-to-back are shown as follows: Figure 5 、 Figure 6 、 Figure 7 and Figure 8 In terms of throughput performance, Figure 5 As shown in Figure 2, both OISL-OSU and OISL-MPLS achieve high bandwidth utilization (L1 rates are 999.96Mbps to 999.97Mbps and 999.99Mbps to 1000.00Mbps, respectively). OISL-OSU outperforms OISL-MPLS when carrying small-granularity services (frame lengths of 68B and 132B). The throughput of OISL-MPLS depends on the network's bandwidth configuration and traffic management policies, and is limited by packet switching efficiency and network congestion. Secondly, the round-trip delay performance is shown in Figure 2. Figure 6 As shown, OISL-OSU adopts a flexible time slot multiplexing method, and intermediate nodes do not need to cache data in a fixed manner. OISL-OSU significantly reduces the encapsulation and cross-processing time, and the single-node delay is greatly reduced. Compared with OISL-MPLS, the single-node delay of OISL-OSU is reduced by 44.72%, 46.26%, 48.78%, 52.11%, 56.29% and 58.58% respectively when the frame length is 68B~1522B. Similarly, OISL-OSU provides a hard pipe, which can effectively reduce packet jitter and is suitable for services that are sensitive to jitter. OISL-MPLS uses packet switching technology, and packet jitter is mainly affected by network congestion and traffic scheduling strategies, but under high load conditions, jitter will increase. As Figure 7 As shown in Figure 2, the jitter of OISL-OSU is reduced by 75.00%, 66.67%, 66.67%, 66.67%, 66.67% and 26.67% respectively when the frame length is 68B~1522B. Finally, the back-to-back performance is shown in Figure 2. Figure 8 As shown in the figure, compared with OISL-MPLS, the average burst rate of OISL-OSU is reduced by 80.91%, 80.53%, 80.29%, 80.15%, 80.08% and 80.05% respectively when the frame length is 68B to 1522B.

[0061] The above disclosure is only a preferred embodiment of the flexible satellite optical network service slicing transmission method of the present invention. Of course, this cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that implementing all or part of the processes of the above embodiment and making equivalent changes in accordance with the claims of the present invention still fall within the scope of the invention.

Claims

1. A method for transmitting elastic satellite optical network service slices, characterized in that: The following steps are involved: Map the customer service to the payload area of ​​the OPU frame, and add the mapped overhead to the OPU overhead area to form an OISL-OPU frame; Based on the OISL-OPU frame, the ODU overhead is added to provide the channel monitoring function to form the OISL-ODU frame; Add OTU overhead based on the OISL-ODU frame to form an OISL-OTU frame; FEC is added to the OISL-OTU frame, and forward error correction is performed by synchronously mapping it to the FEC frame. Finally, the resulting OISL physical layer interface signal is converted into an optical signal for transmission.

2. The elastic satellite optical network service slice transmission method according to claim 1, characterized in that: In "mapping the customer service into the OPU frame payload area, and mapping the overhead to the OPU overhead area to form an OISL-OPU frame", the OISL-OPU frame has a 4-row 3810-column structure, consisting of an OPU overhead and an OPU payload.

3. The elastic satellite optical network service slice transmission method according to claim 1, characterized in that: In "Based on the OISL-OPU frame, an ODU overhead is added to provide a channel monitoring function to form an OISL-ODU frame", the OISL-OPU frame has a 4-row 3824-column structure and consists of an ODU overhead and an OISL-OPU frame.

4. The method for transmitting elastic satellite optical network service slices according to claim 1, wherein: In "Adding an OTU overhead based on an OISL-ODU frame to form an OISL-OTU frame", the OISL-OTU frame adopts a fixed-length frame structure, consisting of an OTU overhead area and an OTU payload area.

5. The method for transmitting elastic satellite optical network service slices according to claim 1, wherein: In the process of "adding FEC to the OISL-OTU frame, performing forward error correction by synchronously mapping it to the FEC frame, and finally converting the resulting OISL physical layer interface signal into an optical signal for transmission," the OISL physical layer interface includes universal OISL-OTU frames, OISL-ODU frames, OISL-OPU frames, and interface-specific OISL-OTU-FEC frames.

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