CN112398734B

CN112398734B - Method, device and system for service transmission

Info

Publication number: CN112398734B
Application number: CN201910749121.9A
Authority: CN
Inventors: 李兢涛; 向俊凌; 卢庆聪
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2019-08-14
Filing date: 2019-08-14
Publication date: 2022-06-10
Anticipated expiration: 2039-08-14
Also published as: CN112398734A; WO2021027434A1

Abstract

The application discloses a method for service transmission, which comprises the following steps: the network equipment receives a first data frame carrying customer service, and de-maps the first data frame to obtain a forwarding label of the customer service; the network equipment acquires the level information of a forwarding label, and determines a first field of the forwarding label according to the level information, wherein the forwarding label comprises the first field and a second field, the first field indicates the forwarding direction of the client service, the second field indicates the identification of the client service, and the level information is used for identifying the first field; and the network equipment forwards the client service according to the first field. By the scheme, the complexity of forwarding the small-particle client service can be simplified, and the bandwidth utilization rate is improved.

Description

Method, device and system for service transmission

Technical Field

The present application relates to the field of communications technologies, and in particular, to a method, an apparatus, and a system for service transmission.

Background

In current communication networks, a large amount of small-particle services exist, and high requirements are put on the cross capacity and the traffic quantity of a service transmission network. In order to improve the carrying capacity of the small-particle service, the industry is continuously going on technical exploration and improvement.

For example, in an Optical Transport Network (OTN), data transmission may be generally performed by using a time division multiplexing technology, and the granularity of partitioning by using a conventional time slot (tributary slot) partitioning manner is relatively large, which results in bandwidth waste of a bearer service. To further improve bandwidth utilization, especially for small grain traffic below 1G rate, there are some discussions in the industry today: an optical data unit k (ODUk) payload area is divided into a plurality of smaller timeslots, for example, an ODU0 is divided into 600 timeslots with a rate of 2M, or a hybrid timeslot structure is adopted, and the timeslots are divided into two stages of timeslots 150M and 10M. The service is mapped to one or more time slots with different rate levels according to the speed condition of the service, the mode of the smaller time slot still continues the traditional time division multiplexing technology to carry out strict time slot division, and compared with the granularity condition of 1.25G and 5G time slots, although the utilization rate of certain bandwidth is improved, the problem of bandwidth waste still exists, and meanwhile, the number of the excessive time slots also brings higher forwarding complexity.

Therefore, for these small-particle services, how to reduce the excessive forwarding complexity caused by the excessive number of services and improve the bandwidth utilization rate are technical problems to be solved urgently.

Disclosure of Invention

Embodiments of the present invention provide a method, an apparatus, and a system for service transmission, which perform dynamic hierarchical division on a small particle forwarding tag to reduce forwarding complexity and improve bandwidth utilization.

In order to achieve the above object, the embodiments of the present invention provide the following technical solutions. In a first aspect, an embodiment of the present invention provides a method for forwarding a service, including: the method comprises the steps that network equipment receives a first data frame carrying customer service, and the first data frame is subjected to demapping to obtain a forwarding label of the customer service; the network equipment acquires the level information of the forwarding label, and determines a first field of the forwarding label according to the level information, wherein the forwarding label comprises the first field and a second field, the first field indicates the forwarding direction of the customer service, the second field indicates the identification of the customer service, and the level information is used for identifying the first field; and the network equipment forwards the client service according to the first field. By the method, the network equipment can realize the forwarding of the client service only by identifying the first field part of the forwarding label, thereby reducing the complexity of the forwarding of the client service and improving the utilization rate of the bandwidth.

The forwarding label may be an incoming label of the node, or an outgoing label of an upstream node. In the application, the nodes and the network equipment have the same meaning, and only the expressions adopted in different scenes are different.

It should be noted that an application scenario of the technical scheme provided in the embodiment of the present application is to directly divide an ODU payload area into n consecutive flexible service units (payload blocks), where n may be infinite. Accordingly, the rate of a single payload block can be infinitely small, and the corresponding flexible tributary unit is formed by one or more payload blocks, so that the rate of the formed flexible tributary unit and the traffic rate are completely consistent as much as possible. The payload block is located in a payload area of the ODU frame, and may include one byte, a plurality of consecutive bytes, or a plurality of consecutive bits. Specifically, the size of a payload block may be an integer multiple of bytes, or may be an integer multiple of 8 bytes, such as 64 bytes, 128 bytes, 192 bytes, or 256 bytes. Alternatively, the sizes of different payload blocks are equal, and the following specific examples are all described by way of example. The payload block may also be referred to as a code block, OSUk, OSUflex, or other name, which is not limited in this application.

In a specific implementation, a payload block is a minimum unit (also referred to as a minimum tributary unit) for carrying a client service, and is also a minimum unit for forwarding after a service receiving node demaps a data frame. The rate of one payload block may be a variable rate or a fixed rate. Multiple payload blocks can be combined to form a flexible tributary unit for carrying client services with corresponding rates. Different small particle services are mapped to corresponding payload blocks according to respective rates, and labels are added to the self-carried overhead of the payload blocks to realize an end-to-end OAM function. Wherein, a plurality of payload blocks carrying the same small granule service may be continuous or discontinuous.

In one possible design, when the number of traffic forwarding directions on the network device changes, the method further includes: the network device changes a length of the first field.

The number of the service forwarding directions on the network equipment changes, including the increase of the number of the forwarding directions and the decrease of the number of the forwarding directions, wherein the increase of the number of the forwarding directions means that the network equipment receives new customer services and goes to the new forwarding directions, or the original customer services are shunted at the network equipment to increase the new forwarding directions; the reduced number of forwarding directions refers to that the original client service on the network device stops sending, or the original client service stops forwarding in at least one direction on the network device.

In one possible design, the method further includes: and the network equipment acquires new hierarchical information, identifies a new first field of the forwarding label according to the new hierarchical information, and forwards the client service according to the new first field.

The first field length of the forwarding label is variable, when the network device receives a new customer service and goes to a new forwarding direction, or the original customer service is shunted at the network device, and the new forwarding direction is increased, the number of the forwarding directions can be increased in time by increasing the first field length, so that the one-to-one correspondence between the first field value and the forwarding directions is ensured, and the dynamic division of the forwarding label is realized. When the original customer service on the network device stops sending or the original customer service stops forwarding in at least one direction on the network device, the redundant bits can be released by reducing the length of the first field. Therefore, the released bit can be used for the customer service identification, and the bandwidth utilization rate is improved.

In a possible design, when the network device obtains new hierarchical information and identifies the first field of the forwarding tag according to the new hierarchical information, the value of the forwarding tag of the existing service or the surviving service may be kept unchanged, and the corresponding forwarding direction is also unchanged. Therefore, the service can be effectively prevented from being damaged, and the implementation complexity is reduced.

In one possible design, after the network device forwards the customer service, the method further includes: and the network equipment updates the forwarding label.

The updating of the forwarding label by the network device means that the forwarding label is updated to an outgoing label of the egress port.

In one possible design, the method further includes: and the network equipment maps the client service to a second data frame, and the second data frame carries the updated forwarding label and sends the second data frame.

In another possible design, the forwarding label of the customer traffic may be updated at an ingress port of a downstream forwarding node.

In one possible design, the first field is located in an overhead area of the first data frame.

Specifically, the first field may be located in a tag field of the overhead area, may also be located in a tag extension field of the overhead area, and may also be partially located in the tag field and partially located in the tag extension field. It is to be understood that when the first field of the forwarding tag is at least two bits, one bit may be located in the tag field and one bit may be located in the tag extension field, and the two bits may not be adjacent. The tag extension field refers to bits located outside a tag field (e.g., 14 bits) of the overhead area, and is extended to serve as a part of the first field of the tag for identifying the forwarding direction, such as unused bits in the overhead or reserved bits. Therefore, the bit of the overhead area can be effectively utilized, and the bandwidth utilization rate is further improved.

In a possible design, the location information of the first field is preconfigured in the network device, or the location information of the first field is carried by an overhead of the first data frame. In this way, the network device may determine the specific location of the first field in the overhead by obtaining the location information of the first field.

In one possible design, the label hierarchy partitioning of ingress ports of the same network device remains consistent. In this way, the forwarding implementation can be further simplified.

In one possible design, the forwarded client traffic may be at least one of Time Division Multiplexed (TDM) client traffic, fixed rate packet (PKT-CBR) client traffic, and variable rate packet (PKT-VBR) client traffic.

In a second aspect, an embodiment of the present invention provides a service forwarding apparatus, which may be used to perform any one of the methods provided by any one of the possible designs of the first aspect. The apparatus may be a communication device.

In one possible design, the device may be divided into functional modules according to a method provided in any one of the possible designs of the first aspect, for example, each functional module may be divided corresponding to each function, or two or more functions may be integrated into one processing module, for example, a forwarding module in an embodiment of the present application.

In one possible design, the apparatus may include: the receiving module is used for receiving a data frame carrying client business; the demapping module is used for demapping the data frame to obtain a forwarding label of the client service; a forwarding module, configured to obtain hierarchy information of the forwarding tag, determine a first field of the forwarding tag according to the hierarchy information, and forward the customer service according to the first field, where the forwarding tag includes the first field and a second field, the first field indicates a forwarding direction of the customer service, the second field indicates an identifier of the customer service, and the hierarchy information indicates the first field of the forwarding tag.

In one possible design, the forwarding module is further configured to: and when the number of the service forwarding directions on the network equipment changes, changing the length of the first field.

In a possible design, the forwarding module is further configured to obtain new hierarchical information, identify a new first field of the forwarding tag according to the new hierarchical information, and forward the client service according to the new first field.

The first field length of the forwarding label is variable, when the network device receives a new customer service and goes to a new forwarding direction, or the original customer service is shunted at the network device, and the new forwarding direction is increased, the number of the forwarding directions can be increased in time by increasing the first field length, so that the one-to-one correspondence between the first field value and the forwarding directions is ensured, and the dynamic division of the forwarding label is realized. When the original customer service on the network equipment stops sending or the original customer service stops forwarding in at least one direction on the network equipment, the redundant bit can be released by reducing the length of the first field, so that the released bit can be used for customer service identification, and the bandwidth utilization rate is improved.

In another possible design, the forwarding module is further configured to update the forwarding label after forwarding the customer service. Updating the forwarding label means updating the forwarding label to an outgoing label of the outgoing port.

In one possible design, the forwarding module is further configured to map the customer service to a second data frame, where the second data frame carries an updated forwarding tag.

In one possible design, the receiving module may be further configured to send the second data frame.

In one possible design, the first field is located in an overhead area of the first data frame and the second data frame.

In a possible design, the location information of the first field is preconfigured in the network device, or the location information of the first field is carried by an overhead of the first data frame.

In one possible design, the forwarding module is further configured to obtain location information of the first field.

In one possible design, the client traffic handled by the forwarding module may be at least one of Time Division Multiplexed (TDM) client traffic, fixed rate packet (PKT-CBR) client traffic, and variable rate packet (PKT-VBR) client traffic.

In a third aspect, an embodiment of the present invention provides a service transmission system, where the system includes a client service source network device, a service forwarding network device, and a sink network device.

In a possible design, the system further includes the customer service transmission device.

In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium for storing instructions that, when executed, will drive an apparatus to perform the foregoing method, where the computer-readable storage ring may also be a computer program product.

In a fifth aspect, the present application provides a computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of the above aspects.

In a sixth aspect, an embodiment of the present invention provides a method for forwarding a service, where the method includes: the network equipment receives customer service from customer equipment, forwards the customer service and maps the customer service to a data frame, wherein the overhead of the data frame carries a forwarding label, the forwarding label comprises a first field and a second field, the first field indicates the forwarding direction of the customer service, and the second field indicates the identification of the customer service.

The network device is a source node of the customer service, and the forwarding tag is an outgoing tag of an outgoing port of the network device and can also be an incoming tag of an incoming port of a downstream forwarding node.

In a seventh aspect, an embodiment of the present invention provides a network device, where the network device is configured to perform any one of the methods provided by any one of the possible designs in the fifth aspect.

In one possible design, the network device may be divided into functional modules according to a method provided in any one of the possible designs of the fifth aspect, for example, the functional modules may be divided corresponding to the functions, or two or more functions may be integrated into one processing module.

In one possible design, the network device may include a cross board, a tributary board, and a line board, wherein the tributary board is used for receiving/sending customer traffic, the cross board is used for forwarding the customer traffic, and the line board is used for implementing multiplexing and demultiplexing, mapping and demapping processing of line-side data frames.

In an eighth aspect, an embodiment of the present invention provides a method for forwarding a service, including: the method comprises the steps that network equipment receives a first data frame carrying customer service, and the first data frame is subjected to demapping to obtain a forwarding label of the customer service; wherein the forwarding label comprises the first field and a second field, the first field indicates a forwarding direction of the customer service, and the second field indicates an identifier of the customer service; and the network equipment client service is sent to the client side equipment. By the method, the network equipment can realize the forwarding of the client service only by identifying the first field part of the forwarding label, thereby reducing the complexity of the forwarding of the client service and improving the utilization rate of the bandwidth.

The network device is a sink node of the customer service, and the sink node may also be a forwarding node of other customer services.

In one possible design, after the network device forwards the customer service, the method further includes: the customer traffic is output from an egress port of the network device.

In one possible design, the method further includes: and the network equipment acquires new layer information, identifies a new first field of the forwarding label according to the new layer information, and forwards the client service according to the new first field.

In one possible design, the method further includes: and the network equipment maps the rest of the client services into a second data frame, and the second data frame carries the updated forwarding labels of the rest of the client services and sends the second data frame.

In a ninth aspect, an embodiment of the present invention provides a network device, configured to perform any one of the methods provided by any one of the possible designs of the seventh aspect.

In one possible design, the network device may be divided into functional modules according to the method provided in any one of the possible designs of the seventh aspect, for example, each functional module may be divided corresponding to each function, or two or more functions may be integrated into one processing module.

In one possible design, the network device may include a cross board, a tributary board, and a line board, the tributary board is used for receiving/sending customer traffic, the cross board is used for forwarding customer traffic, and the line board is used for implementing multiplexing and demultiplexing, mapping and demapping processes of line-side data frames.

It should be understood that, the service transmission apparatus or the communication device or the computer storage medium or the computer program product in any of the transport networks provided above may be applied to the corresponding method provided above, and therefore, the beneficial effects achieved by the method may refer to the beneficial effects in the corresponding method, and are not described herein again.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It is obvious that the following figures reflect only some embodiments of the invention, and that other embodiments of the invention can be obtained by those skilled in the art without inventive exercise. And all such embodiments or implementations are within the scope of the present invention.

Fig. 1 is a schematic diagram of an OTN frame structure applicable to the embodiment of the present application;

fig. 2 is a schematic diagram of a payload block with overhead added, which is applicable to an embodiment of the present application;

fig. 3 is a schematic diagram of a correspondence relationship between an ODU frame and n consecutive payload blocks, which is applicable to the embodiment of the present application;

fig. 4 is a schematic flow chart of a service forwarding node applicable to the embodiment of the present application;

FIG. 5 is a schematic diagram of a hierarchical tag processing space structure suitable for use in embodiments of the present application;

fig. 6 is a flowchart illustrating a method for service transmission in a transport network according to an embodiment of the present application;

fig. 7 is a schematic flowchart of another method for service transmission in a transport network according to an embodiment of the present application;

fig. 8 is a schematic diagram of a payload block structure of a tag extension in an optical transport network according to an embodiment of the present application;

fig. 9 is a schematic diagram of a format of an MPLS label in a packet transport network according to an embodiment of the present application;

fig. 10 is a schematic diagram illustrating a method for service transmission in a packet transport network according to an embodiment of the present application;

fig. 11 is a schematic structural diagram of a service transmission apparatus according to an embodiment of the present application;

fig. 12 is a schematic structural diagram of a service transmission device according to an embodiment of the present application;

Fig. 13 is a schematic view of a service transmission system according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be described in further detail with reference to the accompanying drawings. The particular methods of operation in the method embodiments may also be applied to apparatus embodiments or system embodiments.

The technical scheme provided by the embodiment of the application can be applied to a service transport network, and particularly can be applied to an optical network, such as an OTN, and also can be applied to a packet transport network, such as a PTN. An OTN (or PTN) is usually formed by connecting multiple OTN (or PTN) devices through optical fibers, and is composed of different topological types such as linear type, ring type, and mesh type.

On the electrical layer, OTN frames processed by the OTN device may adopt a frame format defined by International Telecommunication Union-Telecommunication standard sector (ITU-T). Such as the g.709 standard and the g.709.1 standard, etc., to enable interworking between devices. OTN frames of various rates have been defined in the existing standards, such as OPUk frame, ODUk frame, and OTUk frame. Where k is 0, 1, 2, 3, 4, Cn, and flex respectively indicate bit rates of 1.25Gbit/s, 2.5Gbit/s, 10Gbit/s, 40Gbit/s, 100Gbit/s, n 100Gbit/s, and n 1.25Gbit/s (n.gtoreq.2). It should be noted that the above mentioned bit rates are approximate values. For example, the bit rate of the OPU4 frame is 104.35597533Gbit/s more accurately. Other examples are not listed.

Fig. 1 shows a frame structure diagram of an OTUk frame. As shown in fig. 1, an OTUk frame has 4 rows x 4080 columns. The OPUk frame may include an OPUk payload region and an OPUk overhead region (i.e., OPUk OH), the ODUk frame may include an OPUk frame and an ODUk overhead region (i.e., odukoh), and the OTUk frame may include an ODUk frame, an OTUk overhead region (i.e., otukoh), a Frame Alignment Signal (FAS), and a Forward Error Correction (FEC) check region. In the OTUk frame, 1-7 columns of a 1 st row are FAS and multi-frame alignment signal (MFAS), 8-14 columns of the 1 st row are OTUk OH, 1-14 columns of 2-4 th rows are ODUk OH, 15-16 columns of the 1 st-4 th rows are OPUk OH, 17-3824 columns of the 1 st-4 th rows are OPUk payload areas, and 3825-4080 columns of the 1 st-4 th rows are FEC check areas.

It should be noted that, in the technical solution provided in the embodiment of the present application, the ODU payload area is directly divided into n consecutive payload blocks. Optionally, the value of n may be arbitrary, and accordingly, the rate of a single payload block may be variable, and a corresponding flexible tributary unit is configured by one or more payload blocks, which is helpful for making the rate of the configured flexible tributary unit and the traffic rate as consistent as possible. Alternatively, n may take a fixed value, and accordingly, the rate of individual payload blocks may also take a fixed value, e.g., each payload block may comprise 192 bytes. Therefore, each path of client service is facilitated to occupy the most appropriate bandwidth, bandwidth waste is facilitated to be reduced as much as possible, and therefore bandwidth resource utilization rate is greatly improved.

Fig. 2 is a schematic diagram of a payload block structure according to an embodiment of the present invention. As shown in fig. 2, a payload block includes an overhead and a payload, and the overhead may include a tag and other overhead. Wherein the label field contains n bits and can identify 2ⁿIn the case of traffic, the first field of the tag may be used to indicate the forwarding direction of the traffic, which may be, for example, an egress port of the customer traffic.

As described above, the payload block is located in the payload area of the ODU frame, and may include one byte, a plurality of consecutive bytes, or a plurality of consecutive bits. Specifically, the size of a payload block may be an integer multiple of bytes, or may be an integer multiple of 8 bytes, such as 64 bytes, 128 bytes, 192 bytes, or 256 bytes. Alternatively, the sizes of different payload blocks are equal, and the following specific examples are all described by way of example. The payload block may be referred to as OSUflex, or OSUk or other names, which is not limited in this application.

It should be noted that, in an implementation, a payload block is a minimum unit (which may also be referred to as a minimum tributary unit) for carrying client traffic, and is also a minimum unit for forwarding after a service receiving node demaps a data frame. The rate of one payload block may be a variable rate or a fixed rate. A plurality of payload blocks can be combined to form a flexible tributary unit for carrying client traffic of corresponding rate. Different small particle services are mapped to corresponding payload blocks according to respective rates, and labels are added to the self-carried overhead of the payload blocks to realize an end-to-end OAM function. Wherein, a plurality of payload blocks carrying the same client service may be continuous or discontinuous.

Fig. 3 is a schematic diagram of a frame structure according to an embodiment of the present invention. Fig. 3 is based on the ODUk frame included in the OTUk frame shown in fig. 1, where a is a frame structure of the ODUk frame included in the OTUk frame, and b is a schematic diagram of n consecutive payload blocks and an overhead area (i.e., OH) corresponding to the n consecutive payload blocks. Wherein, the overhead area in the b diagram corresponds to (i.e. occupies) odukoh and OPUk OH in the a diagram; the n consecutive payload blocks correspond to (i.e., occupy) the payload area of the ODU frame in the a-diagram. Wherein, the client service carried in each payload block is transmitted in the order of "from top to bottom and from left to right" according to the position of the client service in the payload area. As described above, a plurality of payload blocks carrying the same small granule service may be continuous or discontinuous.

In some embodiments of the present application, for convenience of description, n consecutive payload blocks for carrying multiple small granule services are referred to as one bearer period. The bearer period may also be referred to as a transmission period, a mapping period, or a data intermediate frame, etc. The present embodiment is not limited to this.

Optionally, the number of payload blocks included in each bearer period is the same.

Furthermore, the embodiments of the present application are directed to the following generic terms:

1) small particle service

The small particle service described in the embodiment of the present application may include the following services:

TABLE 1

2) Label (R)

The label can be located in an overhead area of a payload block, occupies a fixed length, has local significance, and is used for indicating the forwarding direction of the service. The forwarding direction may be represented by a cross ID or a line card port identifier. It should be noted that, in different transport networks, the position of the tag and the length of the tag may be slightly different, for example, in an optical transport network, the tag may be an identifier that is located in a payload block overhead of each payload block and occupies a certain bit length after dividing a payload area of an ODU frame into n consecutive payload blocks. For another example, in a packet transport network based on multi-protocol label switching, a label finger is located between a two-layer packet and a three-layer packet in a data packet, and occupies a length of 20 bits, which is used to indicate an identifier of a downstream receiving node service forwarding direction.

3) Data frame

For convenience of description, in the embodiments of the present application, the client traffic that adds overhead and maps into frames and can directly enter the physical layer for transmission is collectively referred to as data frames. The data frame may be an OTN frame in an optical transport network, or may be a packet in a packet transport network. The data frame includes an overhead and a payload. The overhead of the data frame may be used to monitor and manage the client traffic, carry mapping information, and so on. The mapping information may be used to characterize the mapping rules employed in mapping the client traffic to the data frames. For example, the overhead of the data frame includes, but is not limited to, a data frame header indication, a Trail Trace Identifier (TTI), an X-bit interleaved parity (BIP-X), a Backward Error Indication (BEI), a backward defect indication (BD), a status indication (STAT), a timestamp, a sequence identifier, a mapping overhead, and the like. The payload of the data frame is used to carry the customer traffic.

Hereinafter, a service transmission method of a service transport network according to an embodiment of the present application will be described with reference to the drawings.

Fig. 4 is a schematic flow diagram of a service forwarding node in a transport network according to an embodiment of the present application. As shown in fig. 4, the architecture of three nodes for traffic transmission and forwarding in a transport network includes a traffic source node NE1, a sink node NE3, and a forwarding node NE 2. The source node and the sink node may include a tributary board, a cross board NE and a circuit board, and the forwarding node may include a cross board and at least two circuit boards. Fig. 4 is a node structure diagram based on ports, wherein A, B1, C1, D1 and the like are physical ports of a circuit board, and are used for receiving or sending customer services. It will be appreciated that one line card of the node may comprise a plurality of physical ports, as shown, for example, the left and right line cards of the forwarding node each comprise three physical ports for receiving or transmitting traffic. It should be noted that a node generally refers to a network device, and both are synonymous in the present invention.

The control module may obtain a forwarding path of the client service through routing, and specifically, in each node, the node entry port determines a forwarding direction of the client service through the first field of the identification tag, where the forwarding direction may be represented by a cross ID or a port identifier of the circuit board. As shown in fig. 4, customer traffic is accessed by ingress port a of source node N1, reaches egress port B1 of source node N1 with an indication of the cross-ID, writes to source node's egress label L1 and is mapped into frames with the traffic, and is sent to downstream forwarding node N2. An input port C1 of the forwarding node N2 receives the data frame, and after framing, demapping is carried out to obtain a payload block carrying the customer service to be forwarded. The payload block includes overhead and data, where the overhead includes a forwarding label, such as out-label L1 of source node N1 in table 2. Ingress port C1 of forwarding node N2 obtains tag L1 in the payload block and identifies tag L1 as 00.X based on the hierarchy information (e.g., 2.12). The label L1 may include two fields, a first field 00 for indicating the forwarding direction of the customer traffic (e.g., egress port) and a second field Y for indicating the identity of the customer traffic (e.g., traffic ID). The hierarchy information may indicate a division of the first field and the second field for identifying the first field (forwarding direction). For example, the hierarchy information indicates the length or position of the first field, or indicates the length or position of the second field, or may indicate the length or position of both the first field and the second field. The above-mentioned hierarchy information 2.12, "2" indicates that the first field "00" of the tag L1 is 2 bits, and "12" indicates that the second field "X" of the tag L1 is 12 bits. It should be noted that the outgoing label L1 on the source node N1 and the incoming label 01.Y on the forwarding node N2 have the same value, and each includes 14 bits in this embodiment. The difference between the two is that: out-label L1 may not distinguish between the first field and the second field, and identify the in-label as 00.X at ingress port C1 of forwarding node NE2 with hierarchy information 2.12. According to the corresponding relationship between the first field 00 and the output port D2 of the circuit board, the forwarding node N2 assigns the corresponding cross ID of the payload block to 2 by the input port C1, so that the payload block is forwarded to the output port D2 after cross scheduling on the cross board. The payload block updates the outgoing label to L5 at outgoing port D2 and maps into frames to send to the ingress port E2 of the sink node. E2 receives the data frame, and after framing, demapps to obtain the service forwarding unit payload block. An ingress port E2 of the node N3 obtains a tag in the payload block, divides the tag D2 into 1.N according to the hierarchical division information 1.13, determines that a first field of the tag is one bit, and then allocates a corresponding cross ID to the payload block as 2 according to a corresponding relationship between the first field 1 and a port F1 of the circuit board, where the ingress port E2 is configured to forward the cross ID to an egress port F1 after cross scheduling on a cross board of the node N3, and the egress port F1 is an end point of the service. In another example, the out-label of the source node N1, L1, and the out-label of the forwarding node N2, L4, may be divided into a first field and a second field. It should be noted that, when customer traffic is specifically transmitted, the forwarding path includes a source node, a sink node, and at least one forwarding node.

In the above example, the relationship between the forwarding label (including one or both of the incoming label and the outgoing label), the physical port (outgoing port) and the cross ID configured on each node may be represented by the following table:

TABLE 2

It should be noted that, in this embodiment, the update of the forwarding tag occurs at an egress port of the network device, so as to facilitate forwarding of the client service by the downstream network device. As an example, the forwarding tag may also be updated at an ingress port of the network device, specifically, the client traffic is transmitted from the source node N1 to the forwarding node N2, the tag is not updated at the egress port B1 of N1, or a traffic tag is randomly allocated, and then mapped into a data frame to be transmitted to the forwarding node N2, the ingress port C1 of N2 updates the tag to L1, and divides the tag into 00.X according to the hierarchy information, and then allocates a corresponding cross ID to the client traffic according to the first field 00 of the forwarding tag and the corresponding relationship between the first field and the egress port, and forwards the cross ID to the egress port.

In the technical solution provided in this embodiment, through label hierarchical division, a payload block serving as a forwarding unit may implement logical convergence of a client service. Specifically, at a source node of a client service, a network device may perform overall processing on a plurality of payload blocks carrying a plurality of client services, for example, uniformly encode the payload blocks according to a first field of a tag, and then enter a switching network to implement service switching. Meanwhile, when the aggregated customer service is mapped to a cross link for cell switching (ATM), the time consumption of the same customer service as the cell cache of the switching unit is shorter because the overall rate of the aggregated customer service is increased, so that the time delay can be reduced. It should be noted that the length of the switch cell in this embodiment is variable, and may be an integer multiple of the length of the payload block, or may be equal to the length of the payload block, for example 192 bytes in this embodiment, so that the buffering delay may be reduced.

Fig. 5 is a network architecture diagram of a service transmission method in a transport network according to an embodiment of the present application, where the network architecture diagram may include a control module and a network node. The control module is used as a service control layer system, the network to which each node belongs is used as a data bearing layer, the control module can realize a path calculation function by means of the control layer system, and the forwarding process of the small-particle service can be simplified by means of hierarchically divided forwarding labels. The control module may include a set of control elements providing specific functions such as routing and signaling, and by using interfaces, protocols and a signaling system, the control module may dynamically exchange topology information, routing information and other control signaling of the optical network, thereby implementing establishment and removal of an optical path and dynamic allocation of network data. The control module may also be referred to as a controller, a control plane, or the like.

The control module may calculate a path according to related information such as a source node, a destination node, a network bandwidth, a transmission delay, and a traffic distribution condition of each service, obtain label information (for example, an incoming label, an outgoing label, hierarchical information, and the like) of each node, and issue the label information to each node. The ingress port of the node obtains the hierarchical information, so that the ingress tag can be conveniently identified and the service can be forwarded; and obtaining a label from an output port of the node, wherein the label is used for updating the label after cross scheduling/forwarding, and the updated label is used as an input port label of the downstream node. The above correspondence is a correspondence between the first field of the payload block label and the physical port of the circuit board, where the cross ID may be a number of a service port of the cross board.

For example, the service needs to be forwarded to two directions at the node B, the hierarchical partition issued by the node acquisition control module is 1.y, "1" indicates that 1bit in the label domain is used for indicating the service direction, where 0 corresponds to the

cross ID

1, and 1 corresponds to the cross ID 2. Assuming that 50 services exist in the upstream node of the node in two directions, the control module allocates forwarding labels 0.0-0.49 to correspond to the cross IDs 1 and 1.0-1.49 to correspond to the cross IDs 2. The above binary representation for the first field and decimal representation for the second field is used for convenience only and is not a limitation on the representation of the first and second fields of the tag.

In particular, fig. 5 shows a hierarchical process of controlling modules to forward labels. The node A, C, D is a service sending end, the node B is a service receiving end, and the client services carried by the three service sending nodes have two forwarding directions in total at the receiving node B. Taking 14 bits occupied by the label domain as an example, the control module sends label hierarchy information 1.13 to the node B according to the number of directions, and issues a corresponding forwarding label (outgoing label) to the node A, D (since the node C has only a single service direction, direction differentiation by the forwarding label is not needed). Fig. 6 only shows the case where the traffic pipes carried by the node go in two directions, and so on when the number of traffic pipes is larger. For example, when a service pipe carried by the node goes in four directions, the hierarchical division issued by the control module to the service receiving node is changed to 2.12, where 2 indicates that 2 bits are used in the first field in the label, that is, four logic pipes can be distinguished, and the remaining 12 bits are used for distinguishing different services. Thus, each logic pipeline can accommodate 2 at most ¹²4k services. As an example, the label may also be issued by the node through a signaling protocol.

Fig. 6 is a flowchart illustrating a service transmission method in a transport network according to an embodiment of the present application. The method shown in fig. 6 may include the steps of:

s101: the source node transmits a first data frame. Wherein the client traffic carried within the first data frame may be at least one of Time Division Multiplexed (TDM) client traffic, fixed rate packet (PKT-CBR) client traffic, and variable rate packet (PKT-VBR) client traffic. For example, the data frame may be an OTU frame in an optical transport network, or may be a message in a packet transport network. This embodiment takes an OTU frame in an optical transport network as an example for description.

As an example, fig. 6 illustrates a process in which a source node sends a first data frame to a forwarding node, and the forwarding node processes the first data frame.

It should be noted that, before an egress port of the source node sends a data frame, an egress label is written in the egress port, and the egress label is also an ingress label of an ingress port of a downstream forwarding node and is also a forwarding label of the forwarding node.

S102: and the forwarding node receives the first data frame and de-maps to obtain a forwarding label of the client service.

The payload block is the smallest unit (also called as the smallest tributary unit) for carrying the client service, and is also the smallest unit for forwarding after the service receiving node demaps the data frame. The rate of one payload block may be a variable rate or a fixed rate. A plurality of payload blocks can be combined to form a flexible tributary unit for carrying client traffic of corresponding rate. Different client services are mapped to corresponding payload blocks according to respective rates, and labels are added to the overhead of the payload blocks, wherein a plurality of payload blocks carrying the same small-particle service can be continuous or discontinuous. Fig. 3 is a schematic diagram of dividing an ODU frame into n consecutive payload blocks, where, as an example, the rate of each payload block is fixed, and the payload block is used as a minimum unit for carrying client traffic with a fixed rate and forwarding the client traffic as a network device. The payload block comprises an overhead area and a payload area, and the forwarding tag is located in the overhead area of the payload block.

It should be noted that the forwarding label may be an outgoing label of the source node, or an incoming label of the forwarding node.

S103: an input port of the forwarding node acquires the layer information and determines a first field of the forwarding label according to the layer information.

And an entry port of the node reads an entry tag in the overhead of the payload block, acquires the hierarchical information of the entry tag, and divides the entry tag into a first field and a second field according to the hierarchical information. The first field corresponds to the forwarding direction identification of the service, the length is variable and is used as a basis for the receiving end to forward the service, and the part of numerical values are determined by the forwarding direction number of the downstream receiving end of the service; the service identifier of the label corresponding to the second field may include mapping information, which is used to represent a mapping rule used when mapping the client service to the payload block, and is used to identify the service at the destination node or the destination node and perform other processing; or may be a service ID for identifying the client service. As shown in fig. 5, node a and node D transmit two traffics to node B, respectively, and the two traffics transmitted from node a are labeled 0xxxxxxxxxxxxx and 1 yyyyyyyyyyyyyyy, respectively, and the two traffics transmitted from node D are labeled 0 nnnnnnnnnnnnnnnnnn and 1zzzzzzzzz, respectively. And after receiving the data frame and demapping, the node B acquires forwarding labels of four customer services, and divides the label hierarchy into 0.xxxxxxxxxxx, 1.yyyyyyyyyyyy, 0. nnnnnnnnnnnnnnnn and 1.zzzzzzzzzz according to the hierarchy information 1.13. Wherein, the '0' and '1' at the tag prefix are the first field of the tag, and are used for identifying the forwarding direction of the service at the node B; the tag suffix is a service identification, which may be used, for example, to identify the specific location of the client service in the payload region. Therefore, the receiving end can forward the client service only by identifying the first field, and the complexity of reading and forwarding is simplified.

As an example, the hierarchical information of the node B may be issued by the control module. Specifically, the control module obtains each service forwarding path through a service request, a network bandwidth, a transmission delay, a traffic distribution and other related information calculation path of the node A, C, D, further determines that the number of service forwarding directions of the node B is 2, and issues hierarchical information 1.13 of a forwarding label to the node B, where "1" indicates that a first field of the forwarding label has 1 bit, and "13" indicates that a second field of the label has 13 bits. Then, the node B divides the label of the received service into two fields, wherein the first field occupies one bit for identifying the service forwarding direction and may correspond to the output port of the cross board.

S104: and the ingress port of the forwarding node forwards the client service according to the first field of the forwarding label.

As shown in fig. 5, an ingress port (receiving port) of the node B matches an egress direction according to a first field of a payload block ingress tag. Specifically, the first field value of 0 corresponds to forwarding direction 1, which may also be egress port 1, and the first field value of 1 corresponds to forwarding direction 2, which may also be egress port 2. In this way, the ingress port of the node B can forward the traffic to the corresponding direction only by identifying the first field of the tag, which simplifies the forwarding process.

Alternatively, the first field of the tag may be located in the tag field of the overhead. Specifically, the first field may be located in the first several bits of the tag, or may be located in the last several bits of the tag.

Optionally, the first field of the tag may also be located in the tag extension field. The tag extension field may be an unused bit in the overhead or a reserved bit, for example, the overhead format version may be unified, and two bits used for indicating the format version in the overhead of the payload block are used as the tag extension field, or one byte may be reserved for indicating the overhead format version, and the other byte is used as the tag extension field and plays a role together with the bit in the original tag field. In other words, the first field of the forwarding label may be located in the label domain, may be located in the label extension domain, may be located in the label domain partially, and is located in the label extension domain partially, so that there is no limitation on continuity of the first field of the forwarding label and adjacency between bytes. In this way, redundant bits in the tag field do not need to be reserved for the extension of the first field, which is helpful for improving the bandwidth utilization rate. The tag extension field refers to a bit outside an original tag field (e.g., 14 bits) in the overhead, and is extended to be used as a part of the first field of the tag for identifying the forwarding direction, for example, an unused bit in the overhead.

Optionally, the bits of the tag extension and the bits used for identifying the direction in the original tag may be adjacent or not adjacent. In this way, the bits in the overhead can be efficiently utilized.

Optionally, position information may be inserted into the overhead of the data frame and transmitted with the service, and the position information may be used to indicate a position of the first field of the forwarding tag in the overhead and an occupied bit number. Therefore, the receiving end can quickly read the first field of the label and carry out corresponding forwarding.

Optionally, the network device may configure the location information in advance for indicating the location of the first field of the forwarding tag, so that the location information does not occupy the overhead in the data frame, which is beneficial to improving the bandwidth utilization.

S105: the forwarding label is updated at the egress port.

The output port (sending end) updates the incoming label into the outgoing label allocated by the output port so as to identify the forwarding direction of the downstream node. The updated forwarding label also comprises a first field and a second field, the first field is used for identifying the forwarding direction, the second field is used for carrying out service identification, the numerical value of the first field is determined by the forwarding direction number of the downstream node and the corresponding relation, and the corresponding relation refers to the relation between the first field of the forwarding label and the output port of the circuit board. It should be noted that, the hierarchical label division and identification may occur at an ingress port of a node, and the label update may occur at an egress port of the node, so as to simplify the service forwarding process.

S106: the sending end maps the client service to the second data frame and sends the second data frame.

Optionally, for the same client service, the client service received first by the sending end is sent first, and the client service received later is sent later. For different paths of client services, the order of receiving the client service by the sending end and sending the client service by the sending end is not limited in the embodiment of the present application. Based on this, for the payload area within the data frame, transmission may be performed in the order of "from top to bottom, left to right".

Fig. 7 is a flowchart illustrating a service transmission method in a transport network according to an embodiment of the present application. As shown in fig. 7, the method shown in fig. 7 may include the steps of:

s201: the source node transmits a third data frame.

The third data frame carries a new customer service to a new forwarding direction, or a certain original service carried in the third data frame is shunted at a forwarding node, and at least one forwarding direction is added.

Taking fig. 4 as an example, when a new service demand occurs, the control module obtains a forwarding path of the customer service through the routing, the new service reaches the B1 egress port through at least one forwarding according to the forwarding path, and updates the forwarding label to the egress label L1 allocated to the B1 egress port. The new traffic is mapped into frames with the existing traffic and sent by egress port B1 to ingress port C1 of the downstream forwarding node.

S202: and receiving the third data frame by the input port of the forwarding node, and demapping to obtain a forwarding label of the client service.

The forwarding label may be an outgoing label of the source node or an incoming label of the forwarding node.

It should be noted that, in order to adapt to the new forwarding direction number, a certain bit needs to be reserved in the tag field for identifying the new forwarding direction, and a default value of 0 is reserved in part.

S203: and the ingress port acquires new layer information of the forwarding label and identifies a new first field of the forwarding label according to the new layer information.

And the ingress port of the node acquires new layer information of the forwarding label and divides the label into a first field and a second field according to the new layer information. The length of the first field is variable and is used as a basis for forwarding the service at the input port, and the part of numerical values are determined by the forwarding direction number of the downstream node of the service and the corresponding relation; the service identifier of the label corresponding to the second field may include mapping information, which is used to characterize a mapping rule used when mapping the client service to the payload block, and is used to identify the service at the destination node or the destination node and perform other processing. The second field may remain unchanged during the forwarding process.

Specifically, the description will be given by taking fig. 5 as an example. The service aggregation node B has two original forwarding directions, and the hierarchical information is 1.13, where the first field is 0 and corresponds to the forwarding direction 1, and the first field is 1 and corresponds to the forwarding direction 2. When n pieces of client services are newly added to the upstream node and go to the forwarding direction 3, for example, the C node has n pieces of services to be forwarded to the direction 3. Since three service directions need at least two bits for identification, the original level information 1.13 cannot meet the current forwarding requirement, and at this time, the first field of the label needs to be expanded, and the label is hierarchically divided into 2.12 again. Where 2 indicates that there are 2 bits in the label field for the first field, specifically, 00 corresponds to forwarding direction 1, 10 corresponds to forwarding direction 2, 01 corresponds to forwarding direction 3, 11 is temporarily unused. At the moment, the first field of the label is expanded from 1bit to 2 bits, and the dynamic variability of the length of the first field can meet the new service forwarding requirement while simplifying the forwarding complexity.

As an example, the new layer information and correspondence of node B and the new forwarding label of the egress port of node A, C, D may be issued by the control module. Specifically, the new service request of the node C triggers refreshing, the control module re-calculates a path according to the service request of the node A, C, D, the network bandwidth, the transmission delay, the flow distribution and other related information to obtain each service forwarding path including the new service, and further determines that the number of service forwarding directions of the node B is increased to 3, and then issues label hierarchical division 2.12 to the node B, where "2" indicates that the first field of the label is 2 bits, and 12 indicates that the second field of the forwarding label is 12 bits.

Optionally, in the process of updating the forwarding label at the egress port of the node, the surviving forwarding label value may remain unchanged, which helps to maintain the stability of the service and simplify the implementation. Specifically, in the above extension manner, it is assumed that the original forwarding direction of the forwarding node is direction 1 and direction 2, each of the two directions has 50 services, and the label is divided into 1.13, where a first field is 0 corresponding to direction 1 and a first field is 1 corresponding to direction 2. When a service in the forwarding direction 3 is newly added, the control module issues new layer information 2.12, where 00 corresponds to the original direction 1, 10 corresponds to the original direction 2, and 10 corresponds to the newly added direction 3, 11 and is temporarily unused. By this corresponding way, the value of the forwarding label of the relay does not change, the corresponding forwarding direction does not change, but only the label division changes. The specific correspondence is shown in the following table.

TABLE 3

	Direction 1	Direction 2	Direction 3	Direction 4
					Old label	0\|001～0\|049	1\|001～1\|049	No service	No service
New label	00\|01～00\|49	10\|01～10\|49	01\|01～01\|49	No service

Note that, in order to simplify the representation of the tag, the last 12 bits of the tag are represented by numbers 01-49, rather than representing that the forwarding tag is only 4 bits long.

S204: and the ingress port forwards the client service according to the new first field.

And the ingress port distributes corresponding ID of the client service to the egress port according to the corresponding relation between the first field and the egress port, and forwards the ID to the egress port.

Optionally, the bits of the tag extension and the bits used for identifying the direction in the original tag may be adjacent or may not be adjacent. In this way, the bits in the overhead can be effectively utilized.

Optionally, the location information may be inserted into an overhead of the data frame and transmitted with the service, for example, the location information may be carried in an OPU overhead included in the ODU frame or an ODU overhead, such as OH in b of fig. 3. The location information may be used to indicate the location of the first field of the forwarding tag in the overhead and the number of occupied bits. Therefore, the receiving end can quickly read the first field of the label and carry out corresponding forwarding.

S205: the egress port updates the forwarding label.

And the egress port updates the forwarding label into an egress label allocated by the egress port so as to adapt to the forwarding direction of the downstream node. The updated forwarding label also comprises a first field and a second field, the first field is used for identifying the forwarding direction, the second field is used for carrying out service identification, the numerical value of the first field is determined by the forwarding direction number of the downstream node and the corresponding relation, and the corresponding relation refers to the relation between the first field of the forwarding label and the output port of the circuit board. It should be noted that, the hierarchical label division and identification may occur at an ingress port of a node, and the label update may occur at an egress port of the node, so as to simplify the service forwarding process.

S206: the egress port maps the client traffic to a fourth data frame and transmits the fourth data frame.

As an example, when a certain client service stops sending, or stops forwarding in at least one forwarding direction, and the number of forwarding directions of the forwarding node decreases, the same can be achieved by dynamically adjusting the length of the first field. Specifically, still taking fig. 5 as an example, assuming that the service forwarding node B originally has three service directions, the label is divided into 2.12, where the first field value 00 corresponds to the direction 1, 10 corresponds to the direction 2, 01 corresponds to the direction 3, 11 is temporarily unused. When the node C stops the service transmission to the direction 3, since only one bit is needed for identification in the two existing forwarding directions, a bit resource of the first field of the label can be released, and the label is hierarchically divided into 1.13 again. Wherein 1 indicates that 1bit is used for the first field in the forwarding label, specifically, 0 corresponds to the

forwarding direction

1, and 1 corresponds to the forwarding direction 2. The first field of the label is reduced from 2 bits to 1bit, and the released 1bit can be used for service identification, so that the bandwidth utilization rate is improved. This dynamic variability of the first field length can meet changing traffic forwarding requirements while simplifying the forwarding complexity.

It should be noted that, when the number of forwarding directions increases, the above embodiment needs to reserve a certain bit for the new first field in order to adapt to the number of forwarding directions of the node. To ensure that the value of the forwarding tag is unchanged, the default value of the reserved bit may be set to 0, so that the individual bit may be left idle before the first field is extended, as will be understood with reference to table 3. To address this issue and further improve bandwidth utilization, the present application provides the following embodiments.

Fig. 8 is a schematic diagram of a tag extension provided in an embodiment of the present application. The label referred to in this application refers to an identifier that is located in overhead, occupies a certain length, has local meaning, and is used to identify a forwarding direction. Because this application technical scheme can be applicable to in different transport networks such as optical transport network, packet transport network, therefore the length and the position of label probably have some difference. For example, the tag shown in fig. 8 is an identifier that occupies a length of 14 bits in the overhead portion of a payload block, and it should be understood that 14 bits is only one possible setting for the tag length of a payload block and does not constitute a limitation on the tag length. In addition, in the packet transport network based on the multi-protocol label switching, the label finger is located between the two-layer packet and the three-layer packet, occupies a length of 20 bits, and is used for indicating a short identifier of a downstream receiving node service forwarding direction, which can be referred to fig. 9. It should be understood that the type of label is not limited to the above examples. Identifiers that can simplify the forwarding process by hierarchical partitioning can be used as tags for the present application. Fig. 8 illustrates that the length of the tag field is 14bit, and it should be understood that, as the structure of the device is improved, the length of the tag field changes accordingly, and the technical solution provided by the embodiment of the present application is also applicable to similar problems.

As shown in fig. 8, S801 is an internal structure diagram of a payload block, and mainly includes two parts, namely an overhead area and a payload area. It can be seen from S802 that in addition to the 14-bit Label field, there are 2-bit reserved bits in Label before the Label to indicate the overhead format version. Specifically, in order to solve the problem that the reserved bits may cause the bits to be idle, the bits for indicating the overhead format version may be used as the tag extension field. Specifically, format versions can be unified, and on the premise that the original performance is not affected and application ambiguity is generated, the 2 bits are used as the first field of the tag. Thus, regarding the division of the label hierarchy, a form of two fields is still adopted, and the first field represents the first field, the second field represents the service identifier, but in this embodiment, the first field is located in the label extension part, and the original 14-bit label domain is all used for the service identifier.

For example, in the above embodiment, it is assumed that a service is assigned a label of 00000000000101, the receiving end level of the sink node is divided into 2.12, and when the service is received, the label is divided into 00.000000000101. In this embodiment, the hierarchical division is achieved by adding the remaining bits. For the same service as before, the label after expansion is 0000000000000101, and the hierarchy is divided into 2.14, where the 2 bits for making the first field come from the remaining reserved overhead fields. Thus, 14 bits of the original label domain can be completely used as service identification, and can be identified by 2 ¹⁴A stripe service.

Optionally, the bits of the expanded first field may be adjacent or not adjacent. Specifically, the tag extension field part may be used alone as the first field of the tag, or may be used together with the original tag part bit as the first field of the tag to identify the forwarding direction.

Optionally, the receiving end may determine the position of the tag-extended first field in the overhead according to the same predefined algorithm (e.g., sigma-delta algorithm, or algorithm defined by the receiving end and the transmitting end) as that adopted by the transmitting end. Therefore, the sending end does not need to transmit the position information to the receiving end, and the complexity of data processing is reduced.

The above mainly introduces the application of the scheme provided by the embodiment of the present application in the OTN field, and in addition, the technical scheme provided by the present application may also be applied in the packet transport network field. In the field of PTN, the label can realize the high-efficiency forwarding of the service through hierarchical division.

Alternatively, the hierarchical division of the Label may be applied to a Multi-Protocol Label Switching (MPLS) technology.

The multi-protocol label switching is positioned between a link layer and a network layer in a TCP/IP protocol stack, and a short and fixed-length label (label) is used for encapsulating an IP packet and realizing rapid label forwarding on a data plane. The label in MPLS is an identifier with a fixed length, no topology information, and a local meaning, and is used to uniquely identify a Forwarding Equivalence Class (FEC) to which a packet belongs. The forwarding equivalence class refers to an equivalence class generated by grouping data flows with the same characteristic value (the same destination address or the same forwarding level) into one class by using MPLS as a classification forwarding technology, and generally, the same label is allocated to one forwarding equivalence class on one device. Packets of the same forwarding equivalence class will get exactly the same processing in the MPLS network. The label is carried by the head of the message, does not contain topology information, and only has local significance. The label length is 4 bytes, and the encapsulation structure is shown in fig. 9.

Fig. 9 is a schematic diagram of a format of an MPLS label in a packet transport network according to an embodiment of the present application. The tag has 4 fields, and 32 bits are occupied. The label is a label value field, occupies 20 bits, and is used for forwarding data, and this part is a label domain that can be hierarchically divided in the technical scheme provided in the embodiment of the present application. Exp is a reserved field used for testing and can be added with priority information of the message; s is a stack bottom mark, occupies 1 bit, supports the layered structure (namely multiple labels) of the label by MPLS, and is indicated as the bottom label when the S value is 1; ttl (time To live) is the survival time, and has the same meaning as in the IP packet, and occupies 8 bits. Specifically, when a packet enters the MPLS network, an ingress node (edge router) receives the packet and analyzes the header content of the packet to determine the forwarding equivalence class to which the packet belongs, and the control module may allocate a label of a fixed length corresponding to a specific forwarding equivalence class to the packet, establish a corresponding label switching path, encapsulate the label and the packet together, and forward the packet to an intermediate node. The intermediate node forwards the packet according to the label forwarding table corresponding to the label of the packet, and switches the label at the node to adapt to the downstream node without performing any third-layer processing on the label. The egress node (edge router) removes the label in the message and continues to forward the message.

In this process, the technical scheme of hierarchical label division provided by the present application may be adopted when the packet is forwarded in the MPLS network. Specifically, a 20-bit label domain in a message header is hierarchically divided into a first field and a second field, and each node can determine the forwarding direction of the message to perform corresponding forwarding by identifying the first field. For example, assuming that the label of the forwarding node traffic receiving end is divided into 4.16, 16 traffic directions can be distinguished, and each traffic direction can accommodate 64K traffic amount. It should be noted that after the label is hierarchically divided, the label value itself does not change, and the forwarding processing is only divided into two parts, for example, the packet label is 00000000000000001100, and the form is 0000.0000000000001100 after hierarchical division according to the form of 4.16. Wherein, the first field 0000 represents the forwarding direction, and the forwarding node can perform corresponding forwarding only by identifying the part.

As shown in fig. 10, fig. 10 is a schematic view of a service transmission method in an MPLS network according to an embodiment of the present application. The MPLS network includes a plurality of label switching routers (denoted by R in the figure) as traffic forwarding nodes. At a forwarding node R2, 4 packets need to be forwarded to a traffic direction corresponding to a label switched path thereof, where a first field is 0 corresponding to the direction of R2-R3, and a first field is 1 corresponding to the direction of R21-R22-R23. R2 only identifies the first field of the label to forward traffic to different directions separately without the need for traditional label nesting. Since the implementation processes of the specific scheme in the MPLS network and the OTN are very similar, the specific forwarding process may refer to the flowchart shown in fig. 6 and the description of the steps S101 to S106 in the foregoing embodiment, which is not described herein again. By the technical scheme provided by the embodiment of the application, the service forwarding result which is the same as that of label nesting can be realized, and new labels can be prevented from being added, so that the bandwidth utilization rate is improved.

The technical effects of the technical solutions provided by this embodiment can refer to the advantageous effects of the embodiments shown in fig. 6 and fig. 7. And will not be described in detail herein.

The scheme provided by the embodiment of the application is mainly introduced from the perspective of a method. To implement the above functions, it includes hardware structures and/or software modules for performing the respective functions. Those of skill in the art would readily appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as hardware or combinations of hardware and computer software. Whether a function is performed as hardware or computer software drives hardware depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

In the embodiment of the present application, functional modules may be divided on a node or a control side according to the above method, for example, each functional module may be divided corresponding to each function, or two or more functions may be integrated into one processing module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. It should be noted that, in the embodiment of the present application, the division of the module is schematic, and is only one logic function division, and there may be another division manner in actual implementation.

Fig. 11 is a schematic structural diagram of a data transmission apparatus 110 in a transport network according to an embodiment of the present disclosure. As an example, the apparatus 110 may be a source-sink node in the foregoing embodiment, or may be a forwarding node in the foregoing embodiment. As an example, the apparatus 110 may be configured to perform the steps performed by each node in the methods shown in fig. 6 and 7.

The apparatus 110 is in the form of dividing a node into functional modules, and may include a receiving module 1101, a demapping module 1102, and a forwarding module 1103. The receiving module 1101 is configured to perform the following steps: and receiving a data frame carrying client service. The demapping module 1102 is configured to demap the data frame to obtain a forwarding tag of the client service; the forwarding unit is used for acquiring the hierarchy information of the forwarding label, determining a first field of the forwarding label according to the hierarchy information, and forwarding the client service according to the first field. For example, in conjunction with fig. 6, the receiving module 1101 is specifically configured to perform receiving the first data frame in S102; the demapping module 1102 is specifically configured to perform demapping on the first data frame in S102 to obtain a forwarding tag of the customer service; the forwarding module is used for executing S103-S105. For example, with reference to fig. 7, the receiving module 1102 is specifically configured to perform receiving the third data frame in S202; the demapping module 1102 is specifically configured to perform demapping of the third data frame in S202 to obtain a forwarding tag of the customer service; the forwarding module is used for executing S203-S205. It will be appreciated that the data transmission apparatus generally has a transceiver-integrated feature, so the receiving module 1101 can also be used for transmitting data frames, and correspondingly, the demapping module can also be used for mapping the client services to the data frames.

Optionally, the receiving module 1101 is further configured to: location information is received. The location information is used to indicate the specific location of the first field portion in the tag field. Specifically, the location information may be carried in an overhead of the data frame, such as in an OPU overhead or an ODU overhead, or in a packet overhead, and may also be configured in advance.

For the detailed description of the above alternative modes, reference is made to the foregoing method embodiments, which are not described herein again. In addition, for the explanation and the description of the beneficial effects of any of the apparatuses 110 provided above, reference may be made to the corresponding method embodiments described above, and details are not repeated.

Fig. 12 is a schematic diagram of a hardware structure of a data transmission device in a transport network according to an embodiment of the present application. As an example, a network device may include a circuit board, a cross board, a branch circuit board, and may further include a power supply, a fan, an auxiliary board, and a system control and communication board. A network device that is an edge node may have multiple tributary boards. It should be noted that the type and number of plates specifically included in each device may vary according to specific needs. For example, a network device as a core node may not have a tributary board, as shown in fig. 12, which is a hardware structure diagram of a core forwarding node, and does not include a tributary board, and only includes a cross board and at least two circuit boards. Specifically, the wiring board may be divided into a line side optical module and a signal processor. The line side optical module may be a line side optical transceiver for receiving and/or transmitting data frames. The signal processor is used for realizing multiplexing and de-multiplexing or mapping and de-mapping processing of data frames on the line side.

As an example, when device 120 represents a source node, the line card 1201 may be replaced by a branch card. The branch board is used for receiving and transmitting various client services, such as Synchronous Digital Hierarchy (SDH) services, packet services, ethernet services, and fronthaul services. Further, the branch board may be divided into a client-side light module and a signal processor. The client side optical module may be an optical transceiver for receiving and/or transmitting client signals. The signal processor is used for realizing the mapping and de-mapping processing of the client signal to the data frame.

The device 120 is a physical structure corresponding to the apparatus 110, and integrates a circuit board, a cross board, and one or more ports that can be used to implement the service forwarding function. The receiving port of the circuit board can realize the steps of receiving, demapping, receiving the hierarchical information, determining the first field, corresponding to the cross exit and the like in the embodiment; the sending end of the circuit board can implement the functions of updating, mapping into data frames and sending data frames in the above embodiments.

Device 120 may include wiring board 1201, cross board 1202, and wiring board 1203. The

circuit boards

1201 and 1203 include a plurality of physical ports corresponding to the receiving/sending unit 1102 in the logic device 110; the

line boards

1201 and 1203 may implement mapping of client services and demapping of data frames, corresponding to the processing unit 1101 in the logic device 110, and in addition, the cross board 1202 may implement a service forwarding function of the processing unit 1101. Specifically, with reference to fig. 6, the wiring board 1201 is specifically configured to execute S102 to S104; the wiring board 1203 is specifically configured to execute S101, S105, and S106. With reference to fig. 7, the wiring board 1201 is specifically configured to perform S202 to S204; the wiring board 1203 is specifically configured to execute S201, S205, S206.

Optionally, the wiring board 1201 is further configured to receive the position information, and the wiring board 1203 is further configured to transmit the position information. The location information is used to indicate the specific location of the first field portion in the tag field. Specifically, the location information may be written in an overhead of the data frame, such as in an OPU overhead or an ODU overhead, or in a packet overhead.

For the detailed description of the above alternative modes, reference is made to the foregoing method embodiments, which are not described herein again. In addition, for the explanation and the description of the beneficial effects of any one of the apparatuses 120 provided above, reference may be made to the corresponding method embodiments described above, and details are not repeated.

Fig. 13 is a schematic diagram of a system for transmitting traffic in a transport network according to an embodiment of the present application. As shown, the system includes a number of network devices (represented by nodes in the figure), including at least a source node, a sink node, and a forwarding node. According to actual needs, each node may have one or more functions to implement the steps of S101 to S106 in fig. 6 and S201 to S206 in fig. 7. Generally, network devices are classified into optical layer devices, electrical layer devices, and opto-electrical hybrid devices. Optical layer device refers to a device capable of processing optical layer signals, such as: optical Amplifiers (OA). An electrical layer device refers to a device capable of processing electrical layer signals, such as: apparatus capable of processing ODU signals. An opto-electric hybrid device refers to a device that has the capability to process both optical layer signals and electrical layer signals. It should be noted that a network device may integrate a plurality of different functions according to specific integration needs. The technical scheme provided by the application is suitable for network equipment with different forms and integration levels.

The embodiment of the application also provides a chip. The chip integrates a circuit and one or more interfaces for realizing the service forwarding function. When the chip is integrated with a memory, the chip is connected with the optical module through the interface, so that the optical module is used for transmitting the data frame mentioned in the above method embodiment to other communication devices or receiving the data frame transmitted by other communication devices from the optical module. When the chip does not have an integrated memory, the chip can be connected with an external memory through the interface, and the chip realizes the internal execution of the communication device (a sending end or a receiving end) in the embodiment according to the program codes stored in the external memory, and sends and receives data frames by connecting the optical module with the chip. Optionally, the functions supported by the chip may include processing actions of the transmitting end or the receiving end in the embodiments described based on fig. 4, fig. 5, fig. 6, fig. 7, and fig. 10, which are not described herein again.

Those skilled in the art will appreciate that all or part of the steps for implementing the above embodiments may be implemented by a program instructing the associated hardware to perform the steps. The program may be stored in a computer-readable storage medium. The storage medium mentioned above may be a read-only memory, a random access memory, or the like. The processing unit or processor may be a central processing unit, a general purpose processor, an Application Specific Integrated Circuit (ASIC), a microprocessor (DSP), a Field Programmable Gate Array (FPGA) or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof.

The terms "first," "then," "last," and the like in the description and claims of the embodiments of the present application and in the drawings described above are not used to describe a particular order or sequence. It will be appreciated that the data so used may be interchanged under appropriate circumstances such that the embodiments described herein may be practiced otherwise than as specifically illustrated or described herein. Furthermore, the terms "comprises," "comprising," or "having," and any variations thereof, are intended to cover non-exclusive alternatives, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

While the present application has been described in connection with various embodiments, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed application, from a review of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the word "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, apparatus (device), or computer program product. Accordingly, this application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects that may all generally be referred to herein as a "module" or "system. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein. A computer program stored/distributed on a suitable medium supplied together with or as part of other hardware, may also take other distributed forms, such as via the Internet or other wired or wireless telecommunication systems.

The present application has been described with reference to methods, apparatus (devices) and method flow diagrams and/or block diagrams of embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

While the invention has been described in conjunction with specific features and embodiments thereof, it will be evident that various modifications and combinations can be made thereto without departing from the spirit and scope of the invention. Accordingly, the specification and figures are merely exemplary of the invention as defined in the appended claims and are intended to cover any and all modifications, variations, combinations, or equivalents within the scope of the invention. It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A method for forwarding traffic, the method comprising:

the method comprises the steps that network equipment receives a first data frame carrying customer service, and the first data frame is subjected to demapping to obtain a forwarding label of the customer service;

the network equipment acquires the level information of the forwarding label, and determines a first field of the forwarding label according to the level information, wherein the forwarding label comprises the first field and a second field, the first field indicates the forwarding direction of the customer service, the second field indicates the identification of the customer service, and the level information is used for identifying the first field; the forwarding direction is an output port of the client service; the hierarchy information indicates a length or a position of the first field;

and the network equipment forwards the client service according to the first field.

2. The method of claim 1, wherein when the number of traffic forwarding directions on the network device changes, the method further comprises: the network device changes a length of the first field.

3. The method of claim 2, further comprising:

And the network equipment acquires new layer information, identifies a new first field of the forwarding label according to the new layer information, and forwards the client service according to the new first field.

4. The method of claim 1, wherein after the network device forwards the customer traffic, the method further comprises:

and the network equipment updates the forwarding label.

5. The method of claim 4, further comprising:

and the network equipment maps the client service to a second data frame, and the second data frame carries the updated forwarding label and sends the second data frame.

6. The method of claim 1, wherein the first field is located in an overhead area of the first data frame.

7. The method of claim 6, wherein the location information of the first field is pre-configured at the network device, or wherein the location information of the first field is carried by an overhead of the first data frame.

8. A traffic forwarding apparatus, comprising:

The receiving module is used for receiving a first data frame carrying client business;

a demapping module, configured to demap the first data frame to obtain a forwarding tag of the client service;

a forwarding module, configured to obtain hierarchy information of the forwarding tag, determine a first field of the forwarding tag according to the hierarchy information, and forward the client service according to the first field, where the forwarding tag includes the first field and a second field, the first field indicates a forwarding direction of the client service, the second field indicates an identifier of the client service, the hierarchy information indicates the first field of the forwarding tag, the forwarding direction is an egress port of the client service, and the hierarchy information indicates a length or a position of the first field.

9. The apparatus of claim 8, wherein the forwarding module is further configured to:

changing the length of the first field when the number of traffic forwarding directions on the device changes.

10. The apparatus of claim 9, wherein the forwarding module is further configured to obtain new layer information, identify a new first field of the forwarding tag according to the new layer information, and forward the customer service according to the new first field.

11. The apparatus of claim 8, wherein the forwarding module is further configured to update the forwarding label after forwarding the customer service.

12. The apparatus of claim 11, wherein the demapping module is further configured to map the customer traffic to a second data frame, and wherein the second data frame carries an updated forwarding label.

13. The apparatus of claim 12, wherein the receiving module is further configured to send the second data frame.

14. The apparatus of claim 8, wherein the first field is located in an overhead area of the first data frame.

15. The apparatus of claim 8, wherein the location information of the first field is pre-configured at the apparatus, or wherein the location information of the first field is carried by an overhead of the first data frame.

16. The apparatus of claim 15, wherein the forwarding module is further configured to obtain location information of the first field.

17. A traffic transmission system, characterized in that the system comprises a client traffic source network device, a traffic forwarding device according to any of claims 8-16 and a sink network device.

18. A computer-readable storage medium storing instructions that, when executed, cause an apparatus to perform the method of any one of claims 1 to 7.