WO2021027434A1 - Procédé, dispositif et système de transmission de services - Google Patents

Procédé, dispositif et système de transmission de services Download PDF

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Publication number
WO2021027434A1
WO2021027434A1 PCT/CN2020/100283 CN2020100283W WO2021027434A1 WO 2021027434 A1 WO2021027434 A1 WO 2021027434A1 CN 2020100283 W CN2020100283 W CN 2020100283W WO 2021027434 A1 WO2021027434 A1 WO 2021027434A1
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Prior art keywords
forwarding
field
label
service
network device
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PCT/CN2020/100283
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English (en)
Chinese (zh)
Inventor
李兢涛
向俊凌
卢庆聪
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华为技术有限公司
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Publication of WO2021027434A1 publication Critical patent/WO2021027434A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/16—Time-division multiplex systems in which the time allocation to individual channels within a transmission cycle is variable, e.g. to accommodate varying complexity of signals, to vary number of channels transmitted
    • H04J3/1605—Fixed allocated frame structures
    • H04J3/1652—Optical Transport Network [OTN]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/50—Routing or path finding of packets in data switching networks using label swapping, e.g. multi-protocol label switch [MPLS]
    • H04L45/502—Frame based
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J2203/00—Aspects of optical multiplex systems other than those covered by H04J14/05 and H04J14/07
    • H04J2203/0001—Provisions for broadband connections in integrated services digital network using frames of the Optical Transport Network [OTN] or using synchronous transfer mode [STM], e.g. SONET, SDH
    • H04J2203/0051—Network Node Interface, e.g. tandem connections, transit switching
    • H04J2203/0053—Routing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J2203/00—Aspects of optical multiplex systems other than those covered by H04J14/05 and H04J14/07
    • H04J2203/0001—Provisions for broadband connections in integrated services digital network using frames of the Optical Transport Network [OTN] or using synchronous transfer mode [STM], e.g. SONET, SDH
    • H04J2203/0073—Services, e.g. multimedia, GOS, QOS
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J2203/00—Aspects of optical multiplex systems other than those covered by H04J14/05 and H04J14/07
    • H04J2203/0001—Provisions for broadband connections in integrated services digital network using frames of the Optical Transport Network [OTN] or using synchronous transfer mode [STM], e.g. SONET, SDH
    • H04J2203/0089—Multiplexing, e.g. coding, scrambling, SONET
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/50—Routing or path finding of packets in data switching networks using label swapping, e.g. multi-protocol label switch [MPLS]

Definitions

  • This application relates to the field of communication technology, and in particular to a method, device and system for service transmission.
  • OTN optical transport network
  • time-division multiplexing technology is usually used for data transmission, and the granularity of the traditional tributary slot division method is relatively large, and there is a waste of bandwidth for bearer services.
  • ODUk optical data unit-k
  • the embodiment of the present invention provides a method, device, and system for service transmission, which dynamically classifies small-particle forwarding tags to reduce forwarding complexity and improve bandwidth utilization.
  • an embodiment of the present invention provides a service forwarding method, including: a network device receives a first data frame carrying a customer service, and demaps the first data frame to obtain a forwarding label of the customer service; The network device obtains the level information of the forwarding label, and determines the first field of the forwarding label according to the level information, where the forwarding label includes the first field and the second field, and the first field Indicates the forwarding direction of the customer service, the second field indicates the identifier of the customer service, and the hierarchical information is used to identify the first field; the network device treats the customer service according to the first field Forward it.
  • the network device can forward customer services only by identifying the first field part of the forwarding label, which can reduce the complexity of customer service forwarding and improve bandwidth utilization.
  • the forwarding label can be the incoming label of the local node or the outgoing label of the upstream node.
  • nodes and network devices have the same meaning, but different expressions are used in different scenarios.
  • the application scenario of the technical solution provided by the embodiment of the present application is to directly divide the ODU payload area into n continuous flexible service units (payload blocks), where n can be infinitely large.
  • 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, which helps to make the rate and service rate of the formed flexible tributary unit as completely consistent as possible.
  • the payload block is located in the payload area of the ODU frame, and may include one byte or multiple consecutive bytes, or multiple consecutive bits.
  • the size of a payload block can be an integer multiple of bytes, or an integer multiple of 8 bytes, such as 64 bytes, 128 bytes, 192 bytes, or 256 bytes.
  • the sizes of different payload blocks are the same, and the following specific examples are all described as examples.
  • the payload block can also be called a code block, OSUk, OSUflex or other names, which is not limited in this application.
  • a payload block is the smallest unit (also referred to as the smallest branch unit) that bears customer services, and is also the smallest unit for the service receiving node to forward the data frame after demapping.
  • the rate of a payload block can be a variable rate or a fixed rate.
  • Multiple payload blocks can be combined as a flexible tributary unit for carrying client services of corresponding rates. Different small-particle services are mapped into corresponding payload blocks according to their respective rates, and tags are added to the overhead of the payload blocks to implement end-to-end OAM functions. Among them, multiple payload blocks carrying the same small particle service may be continuous or discontinuous.
  • the method further includes: the network device changes the length of the first field.
  • the change in the number of service forwarding directions on the network device includes an increase in the number of forwarding directions and a decrease in the number of forwarding directions.
  • the increase in the number of forwarding directions means that the network device receives new customer services to a new forwarding direction, or the original customer Services are diverted at the network device, and new forwarding directions are added;
  • a decrease in the number of forwarding directions means that 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 method further includes: the network device acquires new layer information, identifies the new first field of the forwarding label according to the new layer information, and the network device according to the new The first field of forwards the customer service.
  • the length of the first field of the forwarding label is variable.
  • a network device receives a new customer service and goes to a new forwarding direction, or when the original customer service is diverted at the network device, a new forwarding direction is added.
  • the length of the first field is increased.
  • the one-to-one correspondence between the value of the first field and the forwarding direction is ensured, and the dynamic division of forwarding labels is realized.
  • the extra bits can be released by reducing the length of the first field. In this way, the released bits can be used for customer service identification, which improves bandwidth utilization.
  • the network device when the network device obtains new layer information and recognizes the first field of the forwarding label according to the new layer information, the value of the forwarding label of the existing service or the surviving service may remain unchanged. Change, the corresponding forwarding direction is also unchanged. In this way, business damage can be effectively avoided, and the complexity of implementation can be reduced.
  • the method further includes: the network device updates the forwarding label.
  • updating the forwarding label by the network device refers to updating the forwarding label to the outgoing label of the outgoing port.
  • the method further includes: the network device maps the customer service to a second data frame, the second data frame carrying an updated forwarding label, and sending the second data frame .
  • the forwarding label of the customer service may be updated at the ingress port of the downstream forwarding node.
  • the first field is located in the overhead area of the first data frame.
  • the first field may be located in the tag field of the overhead area, may also be located in the 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 understandable that when the first field of the forwarding label has at least two bits, one bit may be in the label field and one bit may be in the label extension field, and the two bits may not be adjacent.
  • the tag extension field refers to the bits located outside the tag field (for example, 14 bits) of the overhead area, and is used as a part of the first field of the tag to identify the forwarding direction after being extended, such as unused bits in the overhead or reserved bits. In this way, the bits in the overhead area can be effectively used, and bandwidth utilization is further improved.
  • the location information of the first field is pre-configured in the network device, or the location information of the first field is carried by the overhead of the first data frame. In this way, the network device can determine the specific location of the first field in the overhead by acquiring the location information of the first field.
  • the label hierarchy of the ingress port of the same network device remains consistent. In this way, the forwarding implementation can be further simplified.
  • the forwarded customer service can be at least one of time division multiplexing (TDM) customer service, fixed rate packet (PKT-CBR) customer service, and variable rate packet (PKT-VBR) customer service.
  • TDM time division multiplexing
  • PTT-CBR fixed rate packet
  • PTT-VBR variable rate packet
  • an embodiment of the present invention provides a service forwarding device, which can be used to execute any method provided by any possible design of the first aspect.
  • the device may be a communication device.
  • the device can be divided into functional modules according to the method provided by any one of the possible designs in the first aspect.
  • each functional module can be divided corresponding to each function, or two or Two or more functions are integrated in one processing module, such as the forwarding module in the embodiment of the present application.
  • the device may include: a receiving module, configured to receive data frames carrying customer services; and a demapping module, configured to demap the data frames to obtain the forwarding label of the customer services;
  • the forwarding module is configured to obtain the level information of the forwarding label, determine the first field of the forwarding label according to the level information, and forward the customer service according to the first field, where the forwarding
  • the label includes the first field and a second field, the first field indicates the forwarding direction of the customer service, the second field indicates the identifier of the customer service, and the level information indicates the first field of the forwarding label.
  • the forwarding module is further configured to change the length of the first field when the number of service forwarding directions on the network device changes.
  • the change in the number of service forwarding directions on the network device includes an increase in the number of forwarding directions and a decrease in the number of forwarding directions.
  • the increase in the number of forwarding directions means that the network device receives new customer services to a new forwarding direction, or the original customer Services are diverted at the network device, and new forwarding directions are added;
  • a decrease in the number of forwarding directions means that 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 forwarding module is further configured to obtain new level information, identify the new first field of the forwarding label according to the new level information, and the forwarding module according to the new first field One field forwards the customer service.
  • the length of the first field of the forwarding label is variable.
  • a network device receives a new customer service and goes to a new forwarding direction, or when the original customer service is diverted at the network device, a new forwarding direction is added.
  • the length of the first field is increased.
  • the one-to-one correspondence between the value of the first field and the forwarding direction is ensured, and the dynamic division of forwarding labels is realized.
  • the extra bits can be released by reducing the length of the first field, so that the released bits can be released Used for customer service identification to improve bandwidth utilization.
  • the network device when the network device obtains new layer information and recognizes the first field of the forwarding label according to the new layer information, the value of the forwarding label of the existing service or the surviving service may remain unchanged. Change, the corresponding forwarding direction is also unchanged. In this way, business damage can be effectively avoided, and the complexity of implementation can be reduced.
  • the forwarding module is further configured to update the forwarding label after forwarding the customer service. Updating the forwarding label refers to updating the forwarding label to the outgoing label of the outgoing port.
  • the forwarding module is further configured to map the customer service to a second data frame, and the second data frame carries an updated forwarding label.
  • the receiving module may also be used to send the second data frame.
  • the first field is located in the overhead area of the first data frame and the second data frame.
  • the location information of the first field is pre-configured in the network device, or the location information of the first field is carried by the overhead of the first data frame.
  • the forwarding module is further configured to obtain the location information of the first field.
  • the client services processed by the forwarding module can be time division multiplexing (TDM) client services, fixed rate packet (PKT-CBR) client services, and variable rate packet (PKT-VBR) client services At least one of.
  • TDM time division multiplexing
  • PTT-CBR fixed rate packet
  • PTT-VBR variable rate packet
  • the label hierarchy of the ingress port of the same network device remains consistent. In this way, the forwarding implementation can be further simplified.
  • an embodiment of the present invention provides a service transmission system, which includes a client service source network device, a service forwarding network device, and a sink network device.
  • the system further includes the above-mentioned customer service transmission device.
  • the embodiments of the present invention provide a computer-readable storage medium for storing instructions that will drive the device to execute the foregoing method when the instructions are executed, wherein the computer-readable storage or computer program product.
  • this application provides a computer program product containing instructions, which when running on a computer, causes the computer to execute the methods described in the above aspects
  • an embodiment of the present invention provides a service forwarding method, including: a network device receives client services from client devices, forwards the client services, and maps the client services to data frames, where the overhead of the data frame carries A forwarding label, the forwarding label includes a first field and a second field, the first field indicates the forwarding direction of the customer service, and the second field indicates the identifier of the customer service.
  • the network device is the source node of the customer service, and the forwarding label is the outgoing label of the outgoing port of the network device, and can also be used as the ingress label of the ingress port of the downstream forwarding node.
  • an embodiment of the present invention provides a network device that is configured to execute any method provided by any possible design in the fifth aspect.
  • the network device can be divided into functional modules according to the method provided by any of the possible designs of the fifth aspect.
  • each functional module can be divided corresponding to each function, or two Or two or more functions are integrated in one processing module.
  • the network equipment may include cross-connect boards, tributary boards, and circuit boards.
  • the tributary boards are used to receive/send client services
  • the cross-connect boards are used to forward client services
  • the circuit boards are used to implement line-side data. Frame multiplexing and demultiplexing, mapping and demapping processing.
  • an embodiment of the present invention provides a service forwarding method, including: a network device receives a first data frame carrying a customer service, and demaps the first data frame to obtain a forwarding label of the customer service; Wherein, the forwarding label includes the first field and the second field, the first field indicates the forwarding direction of the customer service, and the second field indicates the identifier of the customer service; the network equipment customer service Send to the client device.
  • the network device can forward customer services only by identifying the first field part of the forwarding label, which can reduce the complexity of customer service forwarding and improve bandwidth utilization.
  • the network device is a sink node of the client service, and the sink node may also be a forwarding node of other client services.
  • the method further includes: outputting the client service from the out port of the network device.
  • the method further includes: the network device changes the length of the first field.
  • the method further includes: the network device acquires new layer information, identifies the new first field of the forwarding label according to the new layer information, and the network device according to the new The first field of forwards the customer service.
  • the network device when the network device obtains new layer information and recognizes the first field of the forwarding label according to the new layer information, the value of the forwarding label of the existing service or the surviving service may remain unchanged. Change, the corresponding forwarding direction is also unchanged. In this way, business damage can be effectively avoided, and the complexity of implementation can be reduced.
  • the method further includes: the network device updates the forwarding label.
  • the method further includes: the network device maps the remaining customer services into a second data frame, the second data frame carrying the updated forwarding label of the remaining customer services, and sending the second Data Frame.
  • the first field is located in the overhead area of the first data frame.
  • the location information of the first field is pre-configured in the network device, or the location information of the first field is carried by the overhead of the first data frame.
  • the label hierarchy of the ingress port of the same network device remains consistent. In this way, the forwarding implementation can be further simplified.
  • the forwarded customer service can be at least one of time division multiplexing (TDM) customer service, fixed rate packet (PKT-CBR) customer service, and variable rate packet (PKT-VBR) customer service.
  • TDM time division multiplexing
  • PTT-CBR fixed rate packet
  • PTT-VBR variable rate packet
  • an embodiment of the present invention provides a network device, which is configured to execute any method provided by any possible design in the seventh aspect.
  • the network device can be divided into functional modules according to the method provided by any of the possible designs of the seventh aspect.
  • each functional module can be divided corresponding to each function, or two Or two or more functions are integrated in one processing module.
  • the network equipment may include cross-connect boards, tributary boards, and circuit boards.
  • the tributary boards are used to receive/send client services
  • the cross-connect boards are used to forward client services
  • the circuit boards are used to implement line-side data. Frame multiplexing and demultiplexing, mapping and demapping processing.
  • any of the service transmission devices or communication equipment or computer storage media or computer program products in the transmission network provided above can be applied to the corresponding methods provided above, and therefore, what it can achieve For the beneficial effects, please refer to the beneficial effects in the corresponding method, which will not be repeated here.
  • FIG. 1 is a schematic diagram of an OTN frame structure applicable to embodiments of the present application
  • FIG. 2 is a schematic diagram of a payload block with additional overhead applicable to an embodiment of the present application
  • FIG. 3 is a schematic diagram of the correspondence between an ODU frame and n consecutive payload blocks applicable to embodiments of the present application;
  • FIG. 4 is a schematic diagram of a service forwarding node flow diagram applicable to embodiments of the present application.
  • FIG. 5 is a schematic diagram of a hierarchical label processing space structure applicable to embodiments of the present application.
  • FIG. 6 is a schematic flowchart of a method for service transmission in a transport network according to an embodiment of this application.
  • FIG. 7 is a schematic flowchart of another method for service transmission in a transport network according to an embodiment of the application.
  • FIG. 8 is a schematic diagram of a payload block structure of a tag extension in an optical transport network provided by an embodiment of this application;
  • FIG. 9 is a schematic diagram of an MPLS label format in a packet transport network provided by an embodiment of the application.
  • FIG. 10 is a schematic diagram of a method for service transmission in a packet transmission network according to an embodiment of this application.
  • FIG. 11 is a schematic structural diagram of a service transmission apparatus provided by an embodiment of this application.
  • FIG. 12 is a schematic structural diagram of a service transmission device provided by an embodiment of this application.
  • FIG. 13 is a schematic diagram of a service transmission system provided by an embodiment of this application.
  • the technical solutions provided by the embodiments of the present application can be applied to a service transmission network, specifically, can be applied to an optical network, such as OTN, and can also be applied to a packet transmission network, such as PTN.
  • An OTN (or PTN) is usually formed by connecting multiple OTN (or PTN) devices through optical fibers, forming different topological types such as linear, ring, and mesh.
  • the OTN frame processed by the OTN device can adopt the frame format defined by the International Telecommunication Union-Telecommunication Standard Sector (ITU-T).
  • ITU-T International Telecommunication Union-Telecommunication Standard Sector
  • the existing standards have defined multiple rate OTN frames, such as OPUk frames, ODUk frames, and OTUk frames.
  • k 0, 1, 2, 3, 4, Cn and flex respectively indicate that the bit rate is 1.25Gbit/s, 2.5Gbit/s, 10Gbit/s, 40Gbit/s, 100Gbit/s, n*100Gbit/s and n*1.25Gbit/s (n ⁇ 2).
  • the bit rates mentioned above are approximate values.
  • the bit rate of the OPU4 frame is more accurately 104.35597533 Gbit/s. Other examples will not be listed one by one.
  • Figure 1 shows a schematic diagram of the frame structure of an OTUk frame.
  • an OTUk frame has 4 rows * 4080 columns.
  • An OPUk frame may include an OPUk payload area and an OPUk overhead area (i.e. OPUk OH)
  • an ODUk frame may include an OPUk frame and an ODUk overhead area (i.e. ODUk OH)
  • an OTUk frame may include an ODUk frame, an OTUk overhead area (i.e. OTUk OH), Frame alignment signal (frame alignment signal, FAS) and forward error correction (forward error correction, FEC) check area.
  • frame alignment signal frame alignment signal, FAS
  • FEC forward error correction
  • columns 1 to 7 in row 1 are FAS and multiframe alignment signal (MFAS)
  • columns 8 to 14 in row 1 are OTUk OH
  • columns 1 to 14 in rows 2 to 4 are ODUk OH
  • columns 15-16 in rows 1 to 4 are OPUk OH
  • columns 17 to 3824 in rows 1 to 4 are OPUk payload areas
  • columns 3825 to 4080 in rows 1 to 4 are FEC check areas.
  • the ODU payload area is directly divided into n consecutive payload blocks.
  • the value of n can be arbitrary.
  • the rate of a single payload block can be variable.
  • the corresponding flexible tributary unit is formed by one or more payload blocks, which helps make the constituted
  • the rate of the flexible tributary unit and the service rate are as consistent as possible.
  • n may take a fixed value.
  • the rate of a single payload block may also be a fixed value.
  • each payload block may include 192 bytes. In this way, it is helpful for each customer service to occupy the most suitable bandwidth, which helps to minimize bandwidth waste, thereby greatly improving bandwidth resource utilization.
  • Fig. 2 is a schematic diagram of a payload block structure provided by an embodiment of the present invention.
  • a payload block includes overhead and payload, and the overhead can include tags and other overheads.
  • the label field contains n bits, which can identify 2 n services.
  • the first field of the label can be used to indicate the forwarding direction of the service.
  • the forwarding direction can be the outgoing port of the customer service.
  • the payload block is located in the payload area of the ODU frame, and may include one byte or multiple consecutive bytes, or multiple consecutive bits.
  • the size of a payload block can be an integer multiple of bytes, or an integer multiple of 8 bytes, such as 64 bytes, 128 bytes, 192 bytes, or 256 bytes.
  • the sizes of different payload blocks are the same, and the following specific examples are all described as examples.
  • the payload block can be called OSUflex, or OSUk or other names, which is not limited in this application.
  • a payload block is the smallest unit (also referred to as the smallest tributary unit) that carries customer services, and is also the smallest unit for the service receiving node to forward the data frame after demapping.
  • the rate of a payload block can be a variable rate or a fixed rate.
  • Multiple payload blocks can be combined as a flexible tributary unit for carrying client services of corresponding rates. Different small-particle services are mapped into corresponding payload blocks according to their respective rates, and tags are added to the overhead of the payload blocks to implement end-to-end OAM functions. Among them, multiple payload blocks carrying the same customer service may be continuous or discontinuous.
  • Fig. 3 is a schematic diagram of a frame structure provided by an embodiment of the present invention.
  • Figure 3 is based on the ODUk frame contained in the OTUk frame shown in Figure 1.
  • Figure a is the frame structure of the ODUk frame contained in the OTUk frame
  • Figure b is the n consecutive payload blocks and the n consecutive
  • the overhead area in figure b corresponds to (that is, occupies) the ODUk OH and OPUk OH in figure a
  • the n consecutive payload blocks correspond to (that is, occupy) the payload area of the ODU frame in figure a.
  • the client services carried in each payload block are transmitted in the order of "from top to bottom, from left to right" where they are located in the payload area.
  • multiple payload blocks carrying the same small particle service can be continuous or discontinuous.
  • n consecutive payload blocks used to carry multiple small-particle services are referred to as a carrying period.
  • the bearer period can also be referred to as a transmission period, a mapping period, or a data intermediate frame. In this regard, the embodiment of the present application does not limit it.
  • the number of payload blocks included in each bearer period is the same
  • the label described in this application can be located in the overhead area of the payload block, occupies a fixed length and has local significance, and is used to indicate the forwarding direction of the service.
  • the forwarding direction can be indicated by the cross ID or the outgoing port ID of the line board.
  • the location of the tag and the length of the tag may be slightly different.
  • the tag described in this embodiment of the application may divide the payload area of the ODU frame into After n consecutive payload blocks, an identifier located in the overhead of each payload block and occupying a certain bit length.
  • the label refers to the data packet located between the layer 2 message and the layer 3 message, occupying 20 bits in length, and is used to indicate the direction of service forwarding of downstream receiving nodes.
  • the client services that add overhead and are mapped into frames and can directly enter the physical layer for transmission are collectively referred to as data frames.
  • the data frame may be an OTN frame in an optical transport network, or a packet in a packet transport network.
  • the data frame includes overhead and payload.
  • the overhead of the data frame can be used to monitor and manage customer services and carry mapping information.
  • the mapping information can be used to characterize the mapping rules used when mapping customer services to data frames.
  • the overhead of a data frame includes but is not limited to data frame header indication, trail trace identifier (TTI), X bit-interleaved parity (BIP-X), and backward error indication ( backward error indication (BEI), backward defect indication (BD), status indication (status, STAT), time stamp, sequence identification, mapping overhead, etc.
  • TTI trail trace identifier
  • BIP-X X bit-interleaved parity
  • BEI backward error indication
  • BD backward defect indication
  • status indication status indication
  • STAT time stamp
  • sequence identification sequence identification
  • mapping overhead etc.
  • the payload of the data frame is used to carry customer services. .
  • FIG. 4 is a schematic diagram of a flow of a service forwarding node in a transport network provided by an embodiment of the application. As shown in Figure 4, it is a structure of three nodes for service transmission and forwarding in the transport network, including a service source node NE1, a sink node NE3, and a forwarding node NE2. Among them, the source node and the sink node may include a tributary board, a cross board NE, and a line board, and the forwarding node may include a cross board and at least two line boards.
  • Figure 4 is a port-based node structure diagram. A, B1, C1, D1, etc. are all physical ports of the circuit board for receiving or sending customer services.
  • one circuit board of a node may include multiple physical ports.
  • the left and right circuit boards of the forwarding node each include three physical ports for receiving or sending services.
  • a node usually refers to a network device, and the two have the same meaning in the present invention.
  • the control module can obtain the forwarding path of the customer service by calculating the path.
  • the ingress port of the node determines the forwarding direction of the customer service through the first field of the identification label.
  • the forwarding direction can be indicated by the cross ID or the port of the circuit board. logo to indicate.
  • the customer service is accessed by the ingress port A of the source node N1, reaches the egress port B1 of the source node N1 through the indication of the cross ID, writes the outgoing label L1 of the source node and maps it into a frame along with the service, and sends it to Downstream forwarding node N2.
  • the ingress port C1 of the forwarding node N2 receives the data frame, demaps it after framing, and obtains the payload block carrying the client service to be forwarded.
  • the payload block includes overhead and data.
  • the overhead includes a forwarding label, such as the outgoing label L1 of the source node N1 in Table 2.
  • the ingress port C1 of the forwarding node N2 obtains the label L1 in the payload block and recognizes the label L1 as 00.X according to the hierarchical information (such as 2.12).
  • the label L1 may include two fields.
  • the first field 00 is used to indicate the forwarding direction of the customer service (for example, outgoing port), and the second field Y is used to indicate the identification of the customer service (for example, the service ID).
  • the hierarchical information may indicate the division of the first field and the second field, and is used to identify the first field (forwarding direction). For example, the hierarchical information indicates the length or position of the first field, or indicates the length or position of the second field, or the length or position of the first field and the second field at the same time.
  • layer information 2.12 “2" is used to indicate that the first field "00" of the label L1 is 2 bits, and “12” is used to indicate that the second field "X" of the label L1 is 12 bits.
  • the outgoing label L1 on the source node N1 has the same value as the incoming label 01.Y on the forwarding node N2, and both include 14 bits in this embodiment.
  • the outgoing label L1 may not distinguish between the first field and the second field, and the incoming label is identified as 00.X through the hierarchical information 2.12 at the incoming port C1 of the forwarding node NE2.
  • the forwarding node N2 assigns the ingress port C1 to the corresponding cross ID of the payload block as 2, so that it is forwarded to the outgoing port D2 after cross scheduling on the cross board.
  • the payload block updates the outgoing label to L5 at the outgoing port D2 and maps it into a frame and sends it to the incoming port E2 of the sink node.
  • E2 receives the data frame, demaps after framing, and obtains the payload block of the service forwarding unit.
  • the ingress port E2 of node N3 obtains the label in the payload block and divides the label D2 into 1.N according to the hierarchical division information 1.13, determines that the first field of the label is a bit, and then according to the first field 1 and the circuit board outgoing port.
  • the corresponding relationship of F1, the corresponding cross ID allocated to the payload block by the ingress port E2 is 2, and is forwarded to the egress port F1 after cross scheduling on the cross board of the node N3, and the egress port F1 is the end of the service.
  • the outgoing label L1 of the source node N1 and the outgoing label L4 of the forwarding node N2 can also be divided into a first field and a second field. It should be noted that when the client service is specifically transmitted, the forwarding path includes a source node, a sink node, and at least one forwarding node.
  • the relationship between the forwarding label (including one or two of the incoming label and the outgoing label), physical port (outgoing port) and cross ID configured on each node can be represented by the following table:
  • the update of the forwarding label occurs at the outgoing port of the network device, which facilitates the forwarding of client services by the downstream network device.
  • the forwarding label can also be updated at the ingress port of the network device.
  • the customer service is transmitted from the source node N1 to the forwarding node N2, and the label is not updated at the egress port B1 of N1, or a service label is randomly assigned. It is mapped into a data frame and sent to the forwarding node N2.
  • the ingress port C1 of N2 updates the label to L1, and divides it into 00.X according to the level information, and then according to the first field 00 of the forwarding label and the difference between the first field and the egress port The corresponding relationship between the two is assigned to the corresponding cross ID of the customer service and forwarded to the outgoing port.
  • the payload block as the forwarding unit can realize the logical convergence of customer services.
  • the network device can perform overall processing on multiple payload blocks carrying multiple customer services, for example, uniformly encode the payload block according to the first field of the label, and then enter the switching network for implementation Service exchange, this overall processing method can simplify the complexity of service processing while enhancing service reliability.
  • the aggregated customer service is mapped to the cross link for cell exchange (Asynchronous Transfer Mode, ATM)
  • the aggregated customer service rate increases, and the cell buffers the same customer service as the switching unit.
  • the time is shorter, which can reduce the time delay.
  • the length of the exchange cell in this embodiment is variable, which can be an integer multiple of the length of the payload block, or it can be equal to the length of the payload block, such as 192 bytes in this embodiment, which can reduce Cache delay.
  • FIG. 5 is a network architecture diagram of a service transmission method in a transport network provided by an embodiment of the application, which may include a control module and a network node.
  • the control module serves as the service control layer system, and the network to which each node belongs serves as the data bearer layer. With the help of the control layer system, it can not only realize the path calculation function, but also simplify the forwarding process of small-particle services through the hierarchically divided forwarding tags.
  • the control module may include a set of control elements that provide specific functions such as routing and signaling.
  • the control module can dynamically exchange optical network topology information, routing information, and other control signaling by using interfaces, protocols, and signaling systems. , To achieve the establishment and removal of optical channels, and the dynamic distribution of network data. It should be noted that the control module may also be called a controller, a control plane, and so on.
  • the control module can calculate the route according to the source node, sink node, network bandwidth, transmission delay, and traffic distribution of each service, and obtain the label information of each node (for example, incoming label, outgoing label, hierarchical information, etc.).
  • the label information is delivered to each node.
  • the ingress port of the node obtains hierarchical information, which is convenient for identifying the incoming label and forwarding services;
  • the outgoing port of the node obtains the outgoing label, which is used to update the label after cross scheduling/forwarding, and the updated label is used as the incoming label of the downstream node.
  • Port label refers to the correspondence between the first field of the payload block label and the physical port of the line board, where the cross ID may be the number of the outgoing service port of the cross board.
  • the service needs to be forwarded to two directions at node B, and the level that the node obtains from the control module is divided into 1.y, "1" means that there is 1 bit in the label field to indicate the direction of the service, where 0 corresponds to the cross ID 1, 1 corresponds to cross ID 2.
  • the control module assigns forwarding labels 0.0 to 0.49 corresponding to cross ID 1, and 1.0 to 1.49 corresponding to cross ID 2.
  • the binary system used in the first field and the decimal system used in the second field above are used for convenience only, and not a restriction on the expression mode of the first field and the second field of the tag.
  • FIG. 5 shows the hierarchical processing process of the forwarding label by the control module.
  • nodes A, C, and D are service sending ends
  • node B is the service receiving end
  • the customer services carried by the three service sending nodes have two forwarding directions in the receiving node B.
  • the control module sends label level information 1.13 to node B according to the number of directions, and delivers the corresponding forwarding label (outgoing label) to nodes A and D (node C has only a single business direction Therefore, there is no need to distinguish between directions by forwarding labels).
  • Figure 6 only shows the situation where the service pipes carried by the node go to two directions. When there are more service pipes, the analogy can be followed.
  • the label can also be issued by the node through a signaling protocol.
  • FIG. 6 is a schematic flowchart of a service transmission method in a transport network provided by an embodiment of this application. The method shown in FIG. 6 may include the following steps:
  • the source node sends the first data frame.
  • the customer service carried in the first data frame may be at least one of time division multiplexing (TDM) customer service, fixed rate packet (PKT-CBR) customer service, and variable rate packet (PKT-VBR) customer service .
  • TDM time division multiplexing
  • PTT-CBR fixed rate packet
  • PTT-VBR variable rate packet
  • the data frame can be an OTU frame in an optical transport network, or a packet in a packet transport network. This embodiment takes the OTU frame in the optical transport network as an example for introduction.
  • Figure 6 shows the process in which the source node sends the first data frame to the forwarding node, and the forwarding node processes it. It can be understood that the source node can also be the upstream forwarding node of the forwarding node, and the embodiment of this application is incorrect. It is restricted.
  • the outgoing port of the source node writes an outgoing label on the outgoing port before sending the data frame
  • the outgoing label is also the incoming label of the incoming port of the downstream forwarding node and the forwarding label of the forwarding node.
  • the forwarding node receives the first data frame and demaps to obtain the forwarding label of the customer service.
  • the payload block is the smallest unit (also referred to as the smallest branch unit) that carries customer services, and is also the smallest unit for the service receiving node to forward the data frame after demapping.
  • the rate of a payload block can be a variable rate or a fixed rate.
  • Multiple payload blocks can be combined as a flexible tributary unit for carrying client services of corresponding rates. Different customer services are mapped to corresponding payload blocks according to their respective rates, and tags are added to the overhead of the payload blocks. Among them, multiple 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.
  • each payload block has a fixed rate and is used to carry fixed-rate client services and serve as the smallest unit for network equipment to forward.
  • the payload block includes an overhead area and a payload area, and the forwarding label is located in the overhead area of the payload block.
  • the foregoing forwarding label may be the outgoing label of the source node, or the incoming label of the forwarding node.
  • the ingress port of the forwarding node obtains level information, and determines the first field of the forwarding label according to the level information.
  • the ingress port of the node reads the incoming tag in the overhead of the payload block and obtains the hierarchical information of the incoming tag, and divides the incoming tag into a first field and a second field according to the hierarchical information.
  • the first field corresponds to the forwarding direction identifier of the service, and the length is variable, as a basis for the receiving end to forward the service, and this part of the value is determined by the forwarding direction number of the downstream receiving end of the service
  • the second field corresponds to the service identifier of the label, It can contain mapping information, which is used to characterize the mapping rules used when mapping the customer service to the payload block, and is used to identify the service at the sink or destination node and perform other processing; it can also be a service ID to identify the customer business.
  • node A and node D respectively send two services to node B
  • the labels of the two services sent from node A are 0xxxxxxxxxxxxxxx and 1yyyyyyyyyyyyyy
  • the labels of the two services sent from node D are 0nnnnnnnnnnnnnnn And 1zzzzzzzzzzzzzzzzzzzzzzzz.
  • the "0" and "1" in the label prefix are the first field of the label, which is used to identify the forwarding direction of the service in Node B;
  • the label suffix is the service identifier, for example, it can be used to identify the client service in the payload.
  • the specific location of the district In this way, the receiving end only needs to identify the first field to forward the customer service, thereby simplifying the complexity of reading and forwarding.
  • the level information of Node B can be issued by the control module. Specifically, the control module calculates routes based on the service requests of nodes A, C, and D, network bandwidth, transmission delay, and traffic distribution, etc., to obtain each service forwarding path, and then determines that the number of service forwarding directions of node B is 2.
  • the layer information 1.13 of the forwarding label is also issued to node B, where "1" means that the first field of the forwarding label has 1 bit, and "13" means that the second field of the label has 13 bits.
  • the node B divides the label of the received service into two fields, where the first field occupies one bit, which is used to identify the forwarding direction of the service, and can correspond to the outgoing port of the cross board.
  • S104 The ingress port of the forwarding node forwards the customer service according to the first field of the forwarding label.
  • the ingress port (receiving port) of node B matches the egress direction according to the first field of the in-tag of the payload block. Specifically, a value of 0 in the first field corresponds to forwarding direction 1, which can also be egress port 1, and a value of 1 in the first field corresponds to forwarding direction 2, or egress port 2. In this way, the ingress port of the node B can forward the service to the corresponding direction only by identifying the first field of the label, which simplifies the forwarding process.
  • the first field of the tag may be located in the tag field of the overhead.
  • the first field may be located in the first few bits of the tag, or may be located in the last few bits of the tag.
  • the first field of the label may also be located in the label extension field.
  • the label extension field can be unused bits in the overhead or reserved bits.
  • the overhead format version can be unified, and the two bits used to indicate the format version in the overhead of the payload block are used as the label extension field, or , One byte can be reserved for indicating the overhead format version, and the other byte is used as the tag extension field, which works together with the bits in the original tag field.
  • the first field of the forwarding label can be all in the label field, or all in the label extension field, part of the label field, and part of the label extension field. Therefore, for the continuity of the first field of the forwarding label and each byte There is no restriction on whether they are adjacent to each other.
  • the label extension field refers to the bits located outside the original label field (for example, 14 bits) in the overhead, and after extension, the first field of the label identifies the forwarding direction, such as the unused bits in the overhead.
  • the extended bits of the label and the bits used to identify the direction in the original label may be adjacent or non-adjacent. In this way, the bits in the overhead can be effectively used.
  • location information can be inserted into the overhead of the data frame and transmitted with the service.
  • the location information can be used to indicate the location of the first field of the forwarding label in the overhead and the number of bits occupied. In this way, the receiving end can quickly read the first field of the tag and forward it accordingly.
  • the outgoing port updates the incoming label to the outgoing label assigned by the outgoing port to identify the forwarding direction of the downstream node.
  • the updated forwarding label also contains the first field and the second field.
  • the first field is used to identify the forwarding direction
  • the second field is used for service identification.
  • the value of the first field is determined by the number of forwarding directions of the downstream node and the corresponding relationship.
  • the corresponding relationship refers to the relationship between the first field of the forwarding label and the outgoing port of the line board.
  • S106 The sending end maps the client service to the second data frame, and sends the second data frame.
  • the customer service received first by the sending end is sent first, and the customer service received later is sent later.
  • the embodiments of this application do not limit the order in which the sender receives and the sender sends the client services. Based on this, the payload area in the data frame can be transmitted in the order of "from top to bottom, from left to right".
  • FIG. 7 is a schematic flowchart of a service transmission method in a transport network provided by an embodiment of this application. As shown in FIG. 7, the method shown in FIG. 7 may include the following steps:
  • S201 The source node sends a third data frame.
  • the third data frame carries the new customer service to a new forwarding direction, or an original service carried in the third data frame is split at the forwarding node, adding at least one forwarding direction.
  • the control module obtains the forwarding path of the customer service by calculating the path.
  • the new service is forwarded at least once to the B1 egress port according to the forwarding path, and the forwarding label is updated to the B1 egress port.
  • the new service is mapped into a frame along with the existing service and sent from the out port B1 to the in port C1 of the downstream forwarding node.
  • the ingress port of the forwarding node receives the third data frame, and demaps to obtain the forwarding label of the customer service.
  • the payload block is the smallest unit (also referred to as the smallest branch unit) that carries customer services, and is also the smallest unit for the service receiving node to forward the data frame after demapping.
  • the rate of a payload block can be a variable rate or a fixed rate.
  • Multiple payload blocks can be combined as a flexible tributary unit for carrying client services of corresponding rates. Different customer services are mapped to corresponding payload blocks according to their respective rates, and tags are added to the overhead of the payload blocks. Among them, multiple 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.
  • each payload block has a fixed rate and is used to carry fixed-rate client services and serve as the smallest unit for network equipment to forward.
  • the payload block includes an overhead area and a payload area, and the forwarding label is located in the overhead area of the payload block.
  • the aforementioned forwarding label may be the outgoing label of the source node, or the incoming label of the forwarding node.
  • the ingress port obtains the new level information of the forwarding label, and identifies the new first field of the forwarding label according to the new level information.
  • the ingress port of the node obtains the new level information of the forwarding label, and re-divides the label into the first field and the second field according to the new level information.
  • the length of the first field is variable, as the basis for service forwarding by the ingress port, and the value of this part is determined by the number of forwarding directions of the downstream nodes of the service and the corresponding relationship;
  • the second field corresponds to the service identifier of the label, and may contain mapping information , Used to characterize the mapping rules used when mapping client services to payload blocks, and used to identify the service at the sink node or destination node and perform other processing.
  • the second field may remain unchanged during the forwarding process.
  • the service convergence node B has two original forwarding directions, and the level information is 1.13.
  • the first field When the first field is 0, it corresponds to forwarding direction 1, and when the first field is 1, it corresponds to forwarding direction 2.
  • the upstream node adds n customer services to the forwarding direction 3, for example, the C node has n services to be forwarded to the direction 3. Since the three service directions require at least two bits for identification, the original layer information 1.13 cannot meet the current forwarding requirements.
  • the first field of the label needs to be expanded to re-divide the label into 2.12. Wherein 2 indicates that there are 2 bits in the label field for the first field.
  • 00 corresponds to forwarding direction 1
  • 10 corresponds to forwarding direction 2
  • 01 corresponds to forwarding direction 3
  • 11 is temporarily unused.
  • the first field of the label is expanded from 1 bit to 2 bits. This dynamic variability of the length of the first field can simplify the forwarding complexity while meeting new service forwarding requirements.
  • the new hierarchical information and corresponding relationship of node B and the new forwarding labels of the outbound ports of nodes A, C, and D can be issued by the control module.
  • a new service request from node C triggers the refresh, and the control module recalculates the path based on the service request of nodes A, C, and D, network bandwidth, transmission delay, and traffic distribution, etc., to obtain various information including the new service.
  • the service forwarding path is determined to increase the number of service forwarding directions of node B to 3, so the label hierarchy division 2.12 is issued to node B, where “2” means the first field of the label is 2 bits, and 12 means the second forwarding label The field is 12 bits.
  • the value of the surviving forwarding label can remain unchanged, which helps maintain the stability of the service and simplify implementation.
  • the original forwarding directions of the forwarding node are direction 1 and direction 2
  • the label is divided into 1.13, where the first field is 0 corresponding to direction 1, and the first field is 1 corresponds to direction 2.
  • the control module issues new level information 2.12, where 00 corresponds to the original direction 1, 10 corresponds to the original direction 2, 10 corresponds to the newly added direction 3, and 11 is temporarily unused.
  • the value of the relay forwarding label does not change, and the corresponding forwarding direction does not change, but only the label division changes.
  • the specific correspondence is shown in the table below.
  • the ingress port is assigned to the corresponding ID of the customer service, and it is forwarded to the egress port.
  • the first field of the tag may be located in the tag field of the overhead.
  • the first field may be located in the first few bits of the tag, or may be located in the last few bits of the tag.
  • the first field of the label may also be located in the label extension field.
  • the label extension field can be unused bits in the overhead or reserved bits.
  • the overhead format version can be unified, and the two bits used to indicate the format version in the overhead of the payload block are used as the label extension field, or , One byte can be reserved for indicating the overhead format version, and the other byte is used as the tag extension field, which works together with the bits in the original tag field.
  • the first field of the forwarding label can be all in the label field, or all in the label extension field, part of the label field, and part of the label extension field. Therefore, for the continuity of the first field of the forwarding label and each byte There is no restriction on whether they are adjacent to each other.
  • the label extension field refers to the bits located outside the original label field (for example, 14 bits) in the overhead, and after extension, the first field of the label identifies the forwarding direction, such as the unused bits in the overhead.
  • the extended bits of the label and the bits used to identify the direction in the original label may be adjacent or non-adjacent. In this way, the bits in the overhead can be effectively used.
  • location information can be inserted into the overhead of the data frame and transmitted with the service.
  • the location information can be carried in the OPU overhead included in the ODU frame or in the ODU overhead, as shown in OH in Figure 3b.
  • 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 bits occupied. In this way, the receiving end can quickly read the first field of the tag and forward it accordingly.
  • the network device may pre-configure location information to indicate the location of the first field of the forwarding label.
  • the location information does not need to occupy the overhead in the data frame, which helps to improve bandwidth utilization.
  • the egress port updates the forwarding label to the egress label assigned by the egress port to adapt to the forwarding direction of the downstream node.
  • the updated forwarding label also contains the first field and the second field.
  • the first field is used to identify the forwarding direction
  • the second field is used for service identification.
  • the value of the first field is determined by the number of forwarding directions of the downstream node and the corresponding relationship.
  • the corresponding relationship refers to the relationship between the first field of the forwarding label and the outgoing port of the line board.
  • the egress port maps the customer service to the fourth data frame, and sends the fourth data frame.
  • the customer service received first by the sending end is sent first, and the customer service received later is sent later.
  • the embodiments of this application do not limit the order in which the sender receives and the sender sends the client services. Based on this, the payload area in the data frame can be transmitted in the order of "from top to bottom, from left to right".
  • 1 indicates that 1 bit in the forwarding label is used for the first field, specifically, 0 corresponds to forwarding direction 1, and 1 corresponds to forwarding direction 2.
  • the first field of the label is reduced from 2bit to 1bit, and the released 1bit can be used for service identification and improve bandwidth utilization.
  • the dynamic variability of the length of the first field can simplify the forwarding complexity while meeting the constantly changing service forwarding requirements.
  • FIG. 8 is a schematic diagram of a label extension provided by an embodiment of the application.
  • the label described in this application refers to an identifier that is located in the overhead, occupies a certain length and has a local meaning, and is used to identify the forwarding direction. Since the technical solution of the present application can be applied to different transmission networks such as optical transmission network and packet transmission network, the length and position of the label may be slightly different.
  • the tag shown in Figure 8 is located in the overhead part of a payload block and occupies a 14-bit identifier. It should be understood that 14-bit is only a possible setting of the tag length of the payload block and does not constitute a restriction on the length of the tag. .
  • the label refers to a short identifier that is located between the layer 2 message and the layer 3 message and occupies a length of 20 bits, which is used to indicate the forwarding direction of downstream receiving nodes.
  • the types of tags are not limited to the above examples. Any identifier that can simplify the forwarding process through hierarchical division can be used as the label of this application.
  • Fig. 8 is illustrated with a tag field length of 14 bits. It should be understood that with the improvement of the device structure, the tag field length changes accordingly, and the technical solutions provided by the embodiments of the present application are also applicable to similar problems.
  • S801 is an internal structure diagram of a payload block, which mainly includes an overhead area and a payload area. It can be seen from S802 that, in addition to the 14-bit label field in the Label, there are also 2 bits reserved before the label to indicate the overhead format version. Specifically, in order to solve the problem that reserved bits may cause bits to be idle, the above-mentioned bits used to indicate the version of the overhead format may be used as the label extension field. Specifically, the format version can be unified, and these 2 bits can be used as the first field of the tag without affecting the original performance and causing application ambiguity.
  • the label hierarchy is still divided in the form of two fields, and the first field represents the first field, and the second field represents the service identifier, but in this embodiment, the first field is located in the extended part of the label, the original 14bit
  • the label field is all used for business identification.
  • the label allocated for a certain service is 00000000000101
  • the receiving end level of the sink node is divided into 2.12
  • its label is divided into 00.000000000101.
  • the level division is achieved by adding the remaining bits.
  • the expanded label is 0000000000000101
  • the hierarchical division is 2.14, where the 2 bits used for the first field come from the remaining reserved overhead fields.
  • the original 14bit label field may be entirely used as service identifier may identify a total of 214 lines of business.
  • the bits of the expanded first field may or may not be adjacent to each other.
  • the label extension field part can be used as the first field of the label alone, or can be used as the first field of the label together with the original label part bits to identify the forwarding direction.
  • the receiving end can determine that the first field of the label extension is in the overhead according to the same predefined algorithm (such as the sigma-delta algorithm, or the algorithm defined by the receiving end and the sending end, etc.) as used by the sending end. s position. In this way, the sender does not need to transmit location information to the receiver, which helps reduce the complexity of data processing.
  • the same predefined algorithm such as the sigma-delta algorithm, or the algorithm defined by the receiving end and the sending end, etc.
  • the foregoing mainly introduces the application of the solution provided in the embodiments of the present application in the OTN field.
  • the technical solution provided in the present application can also be applied in the field of packet transmission networks.
  • tags can also be hierarchically divided to achieve efficient forwarding of services.
  • the hierarchical division of labels can be applied to multi-protocol label switching (Multi-Protocol Label Switching, MPLS) technology.
  • MPLS Multi-Protocol Label Switching
  • Multi-protocol label switching is located between the link layer and the network layer in the TCP/IP protocol stack, and uses short and fixed-length labels to encapsulate IP packets to achieve fast label forwarding on the data plane.
  • the label in MPLS is an identifier with a fixed length, no topology information, and local meaning, which is used to uniquely identify the forwarding equivalence class (FEC) to which a packet belongs.
  • the forwarding equivalence class refers to the equivalence class generated by MPLS as a classified forwarding technology that classifies data streams with the same characteristic value (the same destination address or the same forwarding level) into one class, usually one device Above, the same label is assigned to a forwarding equivalence class.
  • the packets of the same forwarding equivalence class will get exactly the same treatment in the MPLS network.
  • the label is carried by the header of the message, does not contain topology information, and only has a local meaning.
  • the label length is 4 bytes, and the encapsulation structure is shown in Figure 9.
  • FIG. 9 it is a schematic diagram of an MPLS label format in a packet transport network provided by an embodiment of this application.
  • the tag has 4 fields, occupying 32 bits.
  • label is a label value field, which occupies 20 bits and is used to forward data. This part is the label field that can be hierarchically divided in the technical solution provided in the embodiment of this application.
  • Exp is a reserved field, used for experiment, you can add the priority information of the message;
  • S is the identifier of the bottom of the stack, which occupies 1 bit, MPLS supports the layered structure of labels (ie, multiple labels), when the S value is 1, it is the bottom layer Label;
  • TTL Time To Live
  • the ingress node receives the message and analyzes the content of the message header to determine the forwarding equivalence class to which it belongs, and the control module can assign it to a specific forwarding equivalence class Corresponding to the fixed-length label, establish a corresponding label switching path, encapsulate the label and the message, and forward it to the intermediate node.
  • the intermediate node forwards the message according to the label corresponding to the label forwarding table, and exchanges the label at this node to adapt to the downstream node without performing any layer 3 processing on the label.
  • the egress node removes the label in the message and continues forwarding.
  • the technical solution for hierarchically dividing labels provided in this application can be used.
  • the 20-bit label field in the message header is hierarchically divided into a first field and a second field, and each node can determine the forwarding direction of the message and forward it accordingly by identifying the first field.
  • the label of the service receiving end of the forwarding node is divided into 4.16, 16 service directions can be distinguished, and each service direction can accommodate 64K services.
  • the label value itself does not change, and it is divided into two parts when only forwarding processing is performed.
  • the message label is 00000000000000001100, which becomes 0000.0000000000001100 after being hierarchically divided according to the form of 4.16.
  • the first field 0000 indicates the forwarding direction, and the forwarding node only needs to identify this part to perform corresponding forwarding.
  • FIG. 10 is a schematic diagram of a service transmission method in an MPLS network according to an embodiment of the application.
  • the MPLS network contains multiple label switching routers (indicated by R in the figure) as service forwarding nodes.
  • R2 4 packets need to be forwarded to the service direction corresponding to the label switching path.
  • the first field of 0 corresponds to the direction of R2-R3
  • the first field of 1 corresponds to the direction of R21-R22-R23.
  • One direction. R2 can forward services to different directions by only identifying the first field of the label, without the need for traditional label nesting.
  • the specific forwarding process can refer to the flowchart shown in FIG. 6 and the description of the steps S101-S106 in the foregoing embodiment, which will not be repeated here.
  • the technical solution provided by the embodiments of the present application can not only achieve the same service forwarding result as using label nesting, but also avoid adding new labels to improve bandwidth utilization.
  • the embodiment of the present application may divide the node or the control side into functional modules according to the foregoing method examples.
  • each functional module may be divided corresponding to each function, or two or more functions may be integrated into one processing module.
  • the above-mentioned integrated modules can be implemented in the form of hardware or software functional modules. It should be noted that the division of modules in the embodiments of the present application is illustrative, and is only a logical function division, and there may be other division methods in actual implementation.
  • FIG. 11 a schematic structural diagram of a data transmission device 110 in a transport network provided by an embodiment of this application.
  • the apparatus 110 may be the source and sink node in the foregoing embodiment, or may be the forwarding node in the foregoing embodiment.
  • the device 110 can be used to execute the steps performed by each node in the methods shown in Figs. 6 and 7.
  • the device 110 is in the form of dividing nodes 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: receiving data frames carrying client services.
  • the de-mapping module 1102 is used to de-map the data frame to obtain the forwarding label of the customer service; the forwarding unit is used to obtain the level information of the forwarding label, determine the first field of the forwarding label according to the level information, and perform the analysis on the customer service according to the first field. Forward it.
  • FIG. 1102 is used to de-map the data frame to obtain the forwarding label of the customer service
  • the forwarding unit is used to obtain the level information of the forwarding label, determine the first field of the forwarding label according to the level information, and perform the analysis on the customer service according to the first field. Forward it.
  • FIG. 1102 is used to de-map the data frame to obtain the forwarding label of the customer service
  • the forwarding unit is used to obtain
  • the receiving module 1101 is specifically configured to perform the reception of the first data frame in S102; the demapping module 1102 is specifically configured to perform the demapping of the first data frame in S102 to obtain the forwarding label of the customer service; the forwarding module is configured to Perform S103 to S105.
  • the receiving module 1102 is specifically configured to perform the receiving of the third data frame in S202; the demapping module 1102 is specifically configured to perform the demapping of the third data frame in S202 to obtain the forwarding label of the customer service; the forwarding module is used to Perform S203 to S205.
  • the data transmission device usually has the characteristics of an integrated transceiver, so the receiving module 1101 can also be used to send data frames, and correspondingly, the demapping module can also be used to map client services to data frames.
  • the receiving module 1101 is further configured to: receive location information.
  • the location information is used to indicate the specific location of the first field part of the tag in the tag field.
  • the location information may be carried in the overhead of the data frame, such as in the OPU overhead or ODU overhead, or in the message overhead, and may also be pre-configured.
  • FIG. 12 it is a schematic diagram of the hardware structure of a data transmission device in a transport network provided by an embodiment of this application.
  • a network device may include line boards, cross-connect boards, tributary boards, power supplies, fans, auxiliary boards, and system control and communication boards.
  • a network device as an edge node may have multiple tributary boards. It should be noted that, according to specific needs, the specific types and numbers of boards included in each device may be different. For example, a network device as a core node may not have a tributary board.
  • this schematic diagram is a schematic diagram of the hardware structure of a core forwarding node.
  • the tributary board is not included, and only a crossover board and at least two circuit boards are included.
  • the circuit board can 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 sending data frames.
  • the signal processor is used to implement multiplexing and demultiplexing, or mapping and demapping processing of data frames on the line side.
  • the circuit board 1201 may be replaced by a tributary board.
  • the tributary board is used to realize the reception and transmission of various customer services, such as synchronous digital hierarchy (SDH) services, packet services, Ethernet services, and fronthaul services.
  • the tributary board can be divided into a client-side optical module and a signal processor.
  • the client-side optical module may be an optical transceiver for receiving and/or sending client signals.
  • the signal processor is used to realize the mapping and demapping processing of the client signal to the data frame.
  • the device 120 is a physical structure corresponding to the device 110, and integrates a circuit board, a crossover board, and one or more ports that can be used to implement the foregoing service forwarding function.
  • the line board receiving port can implement the steps of service reception, demapping, receiving level information, determining the first field, and corresponding cross exit in the foregoing embodiment;
  • the line board sending end can implement the label update and mapping in the foregoing embodiment Data frame and the function of sending data frame.
  • the device 120 may include a circuit board 1201, a crossover board 1202, and a circuit board 1203.
  • the circuit boards 1201 and 1203 include multiple physical ports, which correspond to the receiving/sending unit 1102 in the logical device 110; the circuit boards 1201 and 1203 can realize the mapping of customer services and the demapping of data frames, corresponding to The processing unit 1101 in the logic device 110, in addition, the cross board 1202 can implement the service forwarding function of the processing unit 1101.
  • the circuit board 1201 is specifically used to perform S102 to S104; the circuit board 1203 is specifically used to perform S101, S105, and S106.
  • the circuit board 1201 is specifically used to perform S202 to S204; the circuit board 1203 is specifically used to perform S201, S205, and S206.
  • the circuit board 1201 is also used to receive location information, and the circuit board 1203 is also used to send location information.
  • the location information is used to indicate the specific location of the first field part of the tag in the tag field.
  • the location information may be written in the overhead of the data frame, such as in the OPU overhead or ODU overhead, or in the message overhead.
  • FIG. 13 it is a schematic diagram of a system for service transmission in a transport network provided by an embodiment of this application.
  • the system includes a certain number of network devices (represented by nodes in the figure), including at least a source node, a sink node, and a forwarding node.
  • each node may have one or more functions to implement the steps S101 to S106 in FIG. 6 and S201 to S206 in FIG. 7.
  • network equipment is divided into optical layer equipment, electrical layer equipment, and photoelectric hybrid equipment.
  • Optical layer equipment refers to equipment capable of processing optical layer signals, such as optical amplifier (optical amplifier, OA).
  • Electrical layer equipment refers to equipment capable of processing electrical layer signals, for example: equipment capable of processing ODU signals.
  • Optoelectronic hybrid equipment refers to equipment capable of processing optical layer signals and electrical layer signals. It should be noted that, according to specific integration needs, a network device can gather multiple different functions. The technical solutions provided in this application are applicable to network devices of different forms and integration levels.
  • the embodiment of the present application also provides a chip.
  • the chip integrates a circuit and one or more interfaces for realizing the above-mentioned service forwarding function.
  • the chip When the memory is integrated in the chip, the chip is connected to the optical module through the interface, so that the optical module is used to send data frames mentioned in the above method embodiments to other communication devices, or to receive data sent by other communication devices from the optical module. Data Frame.
  • the chip When the chip is not integrated with memory, it can be connected to an external memory through this interface, and the chip implements the internal execution of the communication device (transmitting end or receiving end) in the above-mentioned embodiment according to the program code stored in the external memory. Action, and send and receive data frames by connecting the optical module to it.
  • the functions supported by the chip may include processing actions of the sending end or the receiving end in the embodiments described in FIG. 4, FIG. 5, FIG. 6, FIG. 7 and FIG. 10, which will not be repeated here.
  • the program can be stored in a computer-readable storage medium.
  • the aforementioned storage medium may be a read-only memory, a random access memory, and the like.
  • the above-mentioned processing unit or processor may be a central processing unit, a general-purpose processor, an application specific integrated circuit (ASIC), a microprocessor (digital signal processor, DSP), a field programmable gate array (field programmable gate array, FPGA) or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof.
  • the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware, which are collectively referred to herein as "modules” or “systems.”
  • this application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.
  • the computer program is stored/distributed in a suitable medium, provided with other hardware or as a part of the hardware, and can also be distributed in other forms, such as through the Internet or other wired or wireless telecommunication systems.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Data Exchanges In Wide-Area Networks (AREA)

Abstract

L'invention concerne un procédé de transmission de services. Le procédé comprend les étapes suivantes : un dispositif de réseau reçoit une première trame de données transportant un service de client, et démappe la première trame de données pour obtenir une étiquette de transfert du service de client ; le dispositif de réseau acquiert des informations de hiérarchie de l'étiquette de transfert, et détermine un premier champ de l'étiquette de transfert en fonction des informations de hiérarchie, l'étiquette de transfert comprenant le premier champ et un second champ, le premier champ indiquant la direction de transfert du service de client, le second champ indiquant l'identifiant du service de client, et les informations de hiérarchie étant utilisées pour identifier le premier champ; et le dispositif de réseau transfère le service de client en fonction du premier champ. Cette solution permet de simplifier la complexité du transfert d'un service de client à petites particules, ce qui améliore l'utilisation de la bande passante.
PCT/CN2020/100283 2019-08-14 2020-07-03 Procédé, dispositif et système de transmission de services WO2021027434A1 (fr)

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