WO2016090950A1

WO2016090950A1 - Label request message control method and system and upstream and downstream label switching router

Info

Publication number: WO2016090950A1
Application number: PCT/CN2015/087541
Authority: WO
Inventors: 陈尔严; 刘闯; 郭纯宝
Original assignee: 中兴通讯股份有限公司
Priority date: 2014-12-11
Filing date: 2015-08-19
Publication date: 2016-06-16
Also published as: CN105743787A; CN105743787B

Abstract

The present invention relates to the field of communications, and disclosed are a label request message control method and system and upstream and downstream label switching router. The method comprises: in a downstream on-demand label release mode, firstly transmitting a label request message to a downstream label switching router; then receiving a first notification message fed back by the downstream label switching router if the downstream label switching router does not satisfy the label request message of the upstream label switching router, the first notification message comprising a first control message of the label request message and being used to control the transmission of the label request message; parsing the first notification message and controlling subsequent transmission of the label request message according to the parsed first control message.

Description

Control method and system for label request message and upstream and downstream label switching router

Technical field

This application relates to, but is not limited to, a communication domain tag request message.

Background technique

MPLS (Multiprotocol Label Switching) originated from IPv4 (Internet Protocol version 4) and was originally proposed to improve forwarding speed. Its core technology can be extended to a variety of network protocols, including IPv6 ( Internet Protocol version 6, Internet Protocol version 6), IPX (Internet Packet Exchange), Appletalk, and CLNP (Connectionless Network Protocol). The "M" in MPLS refers to supporting multiple network protocols.

MPLS provides a way to map IP addresses to simple fixed-length labels for different packet forwarding and packet switching techniques. Compared with the traditional IP routing method, it analyzes the IP packet header only at the edge of the network during data forwarding, instead of analyzing the IP packet header at each hop; the fixed length label is inserted into the beginning of each packet or cell. It can be used by hardware to quickly exchange packets between two links, saving processing time. MPLS has the following advantages: 1) MPLS encapsulates network layer packets by using fixed-length labels. Routers in the MPLS network no longer look up routes according to the destination IP address, but forward packets according to labels, speeding up the forwarding speed. 2) Each node on the packet forwarding path establishes a virtual channel for packet forwarding by assigning labels, thereby providing a connection-oriented service for the network layer. 3) Support multiple link layer protocols and network layer protocols. MPLS is located between the link layer and the network layer. It can be built on multiple link layer protocols (such as PPP, ATM, Frame Relay, Ethernet, etc.) for multiple network layers (IPv4, IPv6, IPX, etc.). ) Provides connection-oriented services. 4) It not only supports multiple routing protocols, but also supports policy-based constrained routing, which can meet the requirements of many new applications for the network. 5) MPLS was originally proposed as a protocol to improve the forwarding speed of routers, but its use is not limited to this. MPLS can also be used to build VPN (Virtual Private Network) networks, implement traffic engineering, and provide QoS (Quality of Service) guarantees are favored by large-scale IP networks.

The specification and processing description of the label request message in the DOD mode is in the DOD mode, for a certain For a specific FEC, the upstream LSR explicitly sends a label request message to the LSR of the FEC next hop to notify the downstream LSR to allocate a label for the FEC. When the downstream LSR meets the protocol requirements, the FEC is assigned a label and a label mapping message is sent to advertise the binding of the label to the FEC. If the downstream LSR does not meet the requirements of the protocol (for example, the routing table of the downstream LSR does not match the entry of the FEC address prefix, or the other non-label resources are insufficient), the downstream LSR replies with a status code to the upstream LSR. "No route" notification message. According to the requirements of RFC3031, the upstream LSR will resend the label request message to the downstream LSR for the FEC. When the upstream LSR has a large number of such FECs that need to send the request label message, and the downstream LSR cannot satisfy the condition to send the label mapping message to the upstream LSR, the same process will continue over and over again, and the system will always consume more resources to process. These messages, which affect device performance.

Summary of the invention

The following is an overview of the topics detailed in this document. This Summary is not intended to limit the scope of the claims.

This document provides a method and system for controlling a label request message and an upstream and downstream label switching router, which solves the problem that the related technology repeatedly transmits a label request message to waste resources.

A method for controlling a label request message includes:

Sending a label request message to the downstream label switching router in a downstream on-demand label issuing manner, the label request message includes an identifier of a forwarding equivalence class, and the label request message is used by the downstream label switching router. Forward the equivalence class to assign labels;

Receiving, by the downstream label switching router, a first notification message that is fed back by the downstream label switching router, where the first notification message includes a first control message of the label request message, where the first label switching router does not meet the label request message of the upstream label switching router. A notification message is used to control the sending of the label request message;

The first notification message is parsed, and the subsequent transmission of the label request message is controlled according to the parsed first control message.

In an embodiment of the present invention, the first control message includes stopping a message for the forwarding equivalence class, and/or stopping a message for all forwarding equivalence classes; the control obtained according to the parsing The sending of the label request message after the message control includes: if the parsing is to stop the forwarding equivalence class, stop sending the label request message to the forwarding equivalence class; if the parsing is to stop all forwarding equivalents The class message stops sending tag request messages to all forwarding equivalence classes.

In an embodiment of the present invention, after the sending of the label request message after the control according to the first control message obtained by the parsing, when the downstream label switching router satisfies the label request message of the upstream label switching router, receiving the downstream label And a second notification message sent by the switching router, where the second notification message includes a second control message of the label request message, where the second control message includes restoring the message to the forwarding equivalence class, and/or restoring to all forwarding Equivalence class message; parsing the second notification message, if the parsing is to recover the message of the forwarding equivalence class, resending the tag request message to the forwarding equivalence class; if the parsing is to recover all Forwards the message of the equivalence class and resends the tag request message to all forwarding equivalence classes.

In an embodiment of the present invention, the first control message is a message extended to an extended state value of the first notification message, and/or the second control message is extended to the second notification The message in the extended status value of the message.

A method for controlling a label request message includes:

Receiving, in a downstream on-demand label issuing manner, a label request message sent by an upstream label switching router, where the label request message includes an identifier of a forwarding equivalence class, and the label request message is used to allocate the forwarding equivalence class. label;

When the label request message of the upstream label switching router is not satisfied, the first notification message fed back to the upstream label switching router, the first notification message includes a first control message of the label request message, where the first notification message is used The control tag requests the sending of a message.

In an embodiment of the present invention, the label request message that does not satisfy the upstream label switching router includes failing to allocate labels for all forwarding equivalence classes of the upstream label switching router, and/or cannot exchange for the upstream label. The forwarding equivalence class assignment label of the router; the first notification message fed back to the upstream label switching router includes: when the label cannot be allocated for all forwarding equivalence classes of the upstream label switching router, The upstream label switching router feedback includes a first control message for stopping forwarding of all messages of the equivalence class; when the label cannot be allocated for the forwarding equivalence class of the upstream label switching router, the feedback to the upstream label switching router includes Stopping the first control message for the message forwarding the equivalence class.

In an embodiment of the present invention, after the first notification message fed back to the upstream label switching router, when the downstream label switching router satisfies the label request message of the upstream label switching router, the sending is sent to the upstream label switching router. a second notification message, where the second notification message includes a second control message of the label request message, determining whether the feedback includes stopping the first control message for all the messages of the forwarding equivalence class, and if the feedback is All the second control information of the message forwarding the equivalence class; if not fed back, determining whether the first control message including stopping the message of the forwarding equivalence class is fed back, and if the feedback is over, the sending includes restoring the The second control information of the message forwarding the equivalence class.

In an embodiment of the present invention, the first notification message is extended, the first control message is extended to an extended state value of the first notification message, and/or the second notification is The message is extended to extend the second control message to an extended status value of the second notification message.

A method for controlling a label request message includes:

In the downstream on-demand label issuing mode, the upstream label switching router sends a label request message to the downstream label switching router, and the label request message includes an identifier of a forwarding equivalence class, and the label request message is used for the downstream label switching. The router allocates a label to the forwarding equivalence class;

Receiving, by the downstream label switching router, a label request message sent by the upstream label switching router;

When the label request message of the upstream label switching router is not satisfied, the downstream label switching router feeds back a first notification message to the upstream label switching router, where the first notification message includes a first control message of the label request message. The first notification message is used to control sending of the label request message;

The upstream label switching router receives the first notification message fed back by the downstream label switching router, parses the first notification message, and controls transmission of the label request message after the first control message obtained by the parsing.

An upstream label switching router includes a label request sending module and a notification message receiving module:

The label request sending module is configured to send a label request message to the downstream label switching router in a downstream on-demand label issuing manner, where the label request message includes an identifier of a forwarding equivalence class, and the label request message is used for The downstream label switching router allocates a label to the forwarding equivalence class;

The notification message receiving module is configured to: when the downstream label switching router does not satisfy the label request message of the upstream label switching router, receive the first notification message fed back by the downstream label switching router, where the first notification message includes a label request message The first control message, the first notification message is used to control the sending of the label request message; and the first notification message is parsed, and the label after the label request sending module is notified according to the first control message obtained by the parsing The request message is sent.

In an embodiment of the present invention, the first control message includes stopping a message for the forwarding equivalence class, and/or stopping a message for all forwarding equivalence classes; the notification message receiving module is further configured to If the notification message receiving module parses the message that stops the forwarding equivalence class, notifying the tag request sending module to stop sending the tag request message to the forwarding equivalence class; if the parsing is to stop all Forwarding the message of the equivalence class, notifying the tag request sending module to stop sending the tag request message to all forwarding equivalence classes.

In an embodiment of the present invention, after the notification message receiving module notifies the label request message after the label request sending module controls the first control message obtained by the parsing, the downstream label switching router satisfies the upstream label. When the label request message of the router is exchanged, the notification information receiving module is further configured to: receive a second notification message sent by the downstream label switching router, where the second notification message includes a second control message of the label request message, The second control message includes restoring the message to the forwarding equivalence class, and/or restoring the message to all forwarding equivalence classes; the notification information receiving module is further configured to: parse the second notification message, if parsed Recovering the message of the forwarding equivalence class, notifying the tag request sending module to resend the tag request message to the forwarding equivalence class; if the parsing is to recover all the forwarding equivalence class messages, Notifying the tag request sending module to resend the tag request message to all forwarding equivalence classes.

A downstream label switching router includes a label request receiving module and a notification message sending module:

The tag request receiving module is configured to: receive, in a downstream on-demand label issuing mode, a label request message sent by an upstream label switching router, where the label request message includes an identifier of a forwarding equivalence class, and the label request message is set. To: assign a label to the forwarding equivalence class;

When the label request message of the upstream label switching router is not satisfied, the notification message sending module is configured to: a first notification message fed back to the upstream label switching router, where the first notification message includes a first control of the label request message The message, the first notification message is used to control the sending of the label request message.

In an embodiment of the present invention, the label request message that does not satisfy the upstream label switching router includes failing to allocate labels for all forwarding equivalence classes of the upstream label switching router, and/or cannot exchange for the upstream label. The forwarding equivalence class assigning a label of the router; the notification message sending module is further configured to: when the label cannot be allocated for all the forwarding equivalence classes of the upstream label switching router, the feedback to the upstream label switching router includes stopping a first control message for all messages forwarding the equivalence class; when the label cannot be assigned to the forwarding equivalence class of the upstream label switching router, the feedback to the upstream label switching router includes stopping the forwarding of the forwarding equivalent The first control message of the class's message.

In an embodiment of the present invention, after the first notification message fed back to the upstream label switching router, when the downstream label switching router satisfies the label request message of the upstream label switching router, the notification message sending module further sets And sending a second notification message to the upstream label switching router, where the second notification message includes a second control message of the label request message, and determining whether the feedback includes stopping the first control message for all the messages of the forwarding equivalence class. And if the feedback is over, sending the second control information including restoring the message to all forwarding equivalence classes; if not, determining whether the first control message including stopping the message of the forwarding equivalence class is fed back, If feedback is passed, second control information including a message to restore the forwarding equivalence class is transmitted.

A control system for tag request messages, including an upstream label switching router and a downstream label switching router:

The upstream label switching router is configured to send a label request message to the downstream label switching router in a downstream on-demand label issuing manner, where the label request message includes an identifier of a forwarding equivalence class, and the label request message is used for The downstream label switching router is equivalent to the forwarding Class assignment label;

The downstream label switching router is configured to: receive a label request message sent by the upstream label switching router;

When the label request message of the upstream label switching router is not satisfied, the downstream label switching router is further configured to: a first notification message fed back to the upstream label switching router, where the first notification message includes a label request message a first control message, where the first notification message is used to control transmission of a label request message;

The upstream label switching router is further configured to: receive a first notification message fed back by the downstream label switching router, parse the first notification message, and control transmission of the label request message after the first control message obtained by the parsing.

A computer readable storage medium storing computer executable instructions for performing the method of any of the above.

The embodiment of the present invention provides a method and a system for controlling a label request message, and an upstream and downstream label switching router. The method for controlling the label request message in the present application is to send a label request message to the downstream in a downstream label-on-demand label distribution mode. The label switching router, the label request message includes an identifier of the forwarding equivalence class, and the label request message is used by the downstream label switching router to allocate a label for the forwarding equivalence class, and then when the downstream label switching router does not satisfy the label request message of the upstream label switching router Receiving a first notification message fed back by the downstream label switching router, where the first notification message includes a first control message of the label request message, where the first notification message is used to control the sending of the label request message, and the first notification message is parsed according to the parsing The first control message controls the sending of the label request message; when the downstream label switching router satisfies the label request message of the upstream label switching router, the downstream label switching router receives the label mapping message of the forwarding equivalent class. Compared with the related art, when the downstream label switching router fails to meet the label request message of the upstream label switching router, the first label notification message is sent according to the feedback first notification message, so that the upstream label repeatedly sends the label request. Messages reduce the system's resource consumption in processing these messages, conserve resources, and improve system processing performance.

Other aspects will be apparent upon reading and understanding the drawings and detailed description.

BRIEF abstract

1 is a schematic flowchart of a method for controlling a label request message according to Embodiment 1 of the present invention;

2 is a schematic flowchart 1 of a method for controlling a label request message according to Embodiment 2 of the present invention;

3 is a second schematic flowchart of a method for controlling a label request message according to Embodiment 2 of the present invention;

4 is a schematic diagram of a topology structure of an upstream and downstream label switching router in a method for controlling a label request message according to Embodiment 3 of the present invention;

5 is a schematic flowchart 1 of a method for controlling a label request message according to Embodiment 3 of the present invention;

6 is a second schematic flowchart of a method for controlling a label request message according to Embodiment 3 of the present invention;

FIG. 7 is a schematic flowchart 3 of a method for controlling a label request message according to Embodiment 3 of the present invention;

8 is a schematic flowchart 4 of a method for controlling a label request message according to Embodiment 3 of the present invention;

9 is a schematic flowchart 5 of a method for controlling a label request message according to Embodiment 3 of the present invention;

10 is a schematic flowchart 6 of a method for controlling a label request message according to Embodiment 3 of the present invention;

11 is a schematic structural diagram of an upstream label switching router according to Embodiment 4 of the present invention;

12 is a schematic structural diagram of a downstream label switching router according to Embodiment 4 of the present invention;

FIG. 13 is a schematic structural diagram of a control system of a label request message according to Embodiment 4 of the present invention.

Embodiments of the invention

Embodiment 1

The concepts of the related MPLS (Multiprotocol Label Switching) technology are as follows: 1) FEC (Forwarding Equivalence Class) is an important concept in MPLS. MPLS is actually a classification and forwarding technology. It classifies packets with the same forwarding processing method (same destination, same forwarding path or with the same service level, etc.) as a forwarding equivalence class. Packets belonging to the same forwarding equivalence class will get exactly the same processing in the same MPLS network. 2) The label is a fixed length and only has a local An identifier of meaning that uniquely identifies the FEC to which a packet belongs. A tag can only represent one FEC. The tag length is 4 bytes. 3) The LSP (Label Switched Path) is a path formed by the LSR that the forwarding equivalence class passes through in the MPLS network. That is, a unidirectional path from the ingress LSR to the egress LSR is called an LSP. 4) LSR (Label Switching Router) is a device with label publishing capability and label switching capability, and is a basic element in an MPLS network. All LSRs have MPLS capabilities. A network composed of LSRs is called an MPLS domain. On the packet forwarding path, the sender router of the data packet is the upstream LSR of an LSP, and the receiver router is the downstream LSR. 5) Label publishing method: Label publishing means that the label assigned to the FEC is advertised to other LSRs. There are two types of label advertisements used in MPLS: Downstream Unsolicited (DU): For a specific FEC, the downstream LSR allocates labels to the FEC and proactively advertises the labels to the upstream LSR. Downstream on-demand (DOD): For a specific FEC, the upstream LSR requests the downstream LSR to assign a label to the FEC. After receiving the request, the downstream LSR allocates a label to the FEC and advertises the label to the upstream LSR. label. 6) The label allocation control mode refers to the method of establishing an LSP for the FEC. There are two types of label allocation control methods: independent label control mode (Independent): The LSR can advertise label mapping to the LSR connected to it at any time. Ordered label control mode (Ordered): The LSR notifies the label mapping of the FEC to its upstream LSR only if it receives the label assigned by its downstream LSR to an FEC or the LSR is the egress node of the FEC. 7) Label publishing protocol: The label publishing protocol is a signaling protocol of MPLS, which is responsible for dividing FEC, issuing labels, and establishing maintenance LSPs. There are many types of label distribution protocols. There are protocols for label distribution, such as LDP (Label Distribution Protocol), and protocols that support label distribution after extension, such as BGP and RSVP-TE. The technologies of the embodiments of the present invention are all implemented based on LDP specified in RFC 5036.

The method for controlling the label request message in this embodiment, as shown in FIG. 1, includes the following steps:

Step S101: Send a label request message to the downstream label switching router in the downstream on-demand label issuing mode;

In this step, the label request message includes an identifier for forwarding the equivalence class, and the label request message is used by the downstream label switching router to allocate a label for the forwarding equivalence class; the upstream LSR sends a label request to a certain FEC that has not yet assigned the label. Downstream LSR. In the DOD mode, for one has not yet There is a forwarding equivalence class FEC that obtains a label from the downstream LSR, and the upstream LSR sends a label request message to the downstream LSR; and records related content of the label request message, so that when the first notification message of the feedback is received later, The corresponding FEC is identified.

Step S102: Receive a first notification message fed back by the downstream label switching router when the downstream label switching router does not satisfy the label request message of the upstream label switching router;

In this step, the first notification message includes a first control message of the label request message, and the first notification message is used to control the sending of the label request message. When the downstream LSR receives the label request message of the upstream LSR for a certain FEC, it is determined. When the label request message of the upstream LSR is not satisfied, the first notification message is fed back to the upstream LSR. The first notification message is used to control the sending of the label request message. It should be understood as the first notification message, which can be used to inform the upstream LSR. The LSR cannot satisfy the information of the label request message message and causes it to stop the transmission of the subsequent label request message. The result of the determination that the downstream LSR cannot satisfy the label request message of the upstream LSR includes two cases: 1. The FEC allocation label and the binding label of the advertisement label and the FEC cannot be allocated for the label request message. For example, the downstream LSR learns that the route is incomplete, and there is no entry in the routing table that matches the FEC address prefix. 2. The next hop of the upstream LSR cannot be used to assign labels and advertisement labels to the FEC of the LSR. For example, the downstream LSR has configured a policy to prohibit the advertisement of the label to the upstream LSR; or the downstream LSR uses the ordered label control mode and has not received the label mapping message from its downstream LSR. When receiving the label request message of the upstream LSR for an FEC, the downstream LSR needs to record the related content of the label request message, so that when the "no route" notification message is sent subsequently, the related fields required by the protocol can be correctly filled.

Step S103: Parsing the first notification message, and controlling transmission of the subsequent label request message according to the parsed first control message.

In this step, after receiving the first notification message fed back by the downstream LSR, the upstream LSR parses the content of the first notification message, that is, parses the first control message, and controls the label request message according to the content of the first control message. The sending, where the control tag request message is sent, includes stopping the sending of a request for the FEC tag request message, and further includes stopping sending all unassigned FEC tag request messages.

Optionally, the first control message includes stopping the message of the forwarding equivalence class, and/or stopping the message for all forwarding equivalence classes; and controlling, according to the parsed control message, in the foregoing step S103 The sending of the subsequent label request message includes: if the parsing is to stop forwarding the equivalence class message, the sending of the label request message to the forwarding equivalence class is stopped; if the parsing is to stop the message of all forwarding equivalence classes, the message is stopped. A label request message is sent for all forwarding equivalence classes. Optionally, the first notification message includes an extended status value, and parsing the first notification message includes parsing an extended status value of the first notification message, and controlling transmission of the label request message according to the parsed extended status value. For example, the first notification message can be an extended "no route" notification message. The first control message includes a message that stops the forwarding equivalence class and can be correspondingly set to a first preset extended state value, and the message for stopping all forwarding equivalence classes can be correspondingly set to a third preset extended state value. The sending of the label request message according to the extended state value obtained by the parsing comprises: if the parsed extended status value is the first preset extended status value, stopping sending the label request message to the forwarding equivalence class, and continuing to the other forwarding equivalence class Sending a label request message; if the parsed extended status value is a third preset extended status value, stopping sending a label request message to all forwarding equivalence classes. When the first notification message is an extended "no route" notification message, the extended "no route" notification message extension status value is parsed to control the transmission of the label request message. For example, when the downstream LSR receives the label request message of the upstream LSR for a certain FEC, and determines that the label request message of the upstream LSR cannot be satisfied, the downstream LSR is notified by sending an extended “no route” notification message. The label request message is repeatedly sent; the upstream receives the "no route" notification message of the extension to stop sending the label request message, and controls the sending of the label request message according to the extended status value in the "no route" notification message that parses the extension. This can prevent the upstream LSR from repeatedly sending label request messages, reducing the resource consumption of the system in processing these messages, and improving the processing performance of the system. When the downstream label switching router satisfies the label request message of the upstream label switching router, the downstream label switching router receives the label mapping message of the forwarding equivalent class. For example, when the downstream LSR meets the protocol requirements, the FEC is assigned a label and a label mapping message is sent to advertise the label's binding to the FEC.

After the foregoing step S103, that is, after the transmission of the label request message after the control according to the first control message obtained by the parsing, when the downstream label switching router satisfies the label request message of the upstream label switching router, the receiving of the label sent by the downstream label switching router a second notification message, the second notification message comprising a second control message of the label request message, the second control message comprising: restoring the message to the forwarding equivalence class, and/or restoring the message to all forwarding equivalence classes; parsing the second notification message If the parsing is to restore the forwarding equivalence class message, the label request message is sent again to the forwarding equivalence class; if the parsing is to recover all the forwarding equivalence class messages, the forwarding is equivalent to all forwarding. The class sends a tag request message. Optionally, the second notification message includes an extended status value, and parsing the second notification message includes parsing an extended status value of the second notification message, and controlling transmission of the label request message according to the parsed extended status value. For example, the second notification message can be an extended "no route" notification message. The second control message includes a message that restores the forwarding equivalence class, and can be correspondingly set to a second preset extended state value, and the message for restoring all forwarding equivalence classes can be correspondingly set to a fourth preset extended state value. The sending of the label request message according to the extended state value obtained by the parsing comprises: if the parsed extended status value is the second preset extended status value, resuming sending the label request message to the forwarding equivalence class; if the parsed extended status value is obtained If the state value is extended for the fourth preset, the label request message is resumed for all forwarding equivalence classes. When the second notification message is an extended "no route" notification message, the extended "no route" notification message extension status value is parsed to control the transmission of the label request message. For example, when the downstream LSR re-learns or recovers the fault, and determines that the label request message of the upstream LSR is satisfied, the upstream LSR is notified to resend the label request message by sending an extended “no route” notification message; The extended "no route" notification message resumes sending the tag request message, and controls the transmission of the tag request message based on the extended status value in the "no route" notification message parsing the extension. In this way, the upstream LSR can know the downstream LSR situation, and control the sending of the label request message according to the situation, thereby improving the processing performance of the system.

Embodiment 2

The method for controlling the label request message in this embodiment, as shown in FIG. 2, includes the following steps:

Step S201: Receive a label request message sent by an upstream label switching router in a downstream label-on-demand label issuing manner;

In this step, the label request message includes an identifier for forwarding the equivalence class, and the label request message is used by the downstream label switching router to allocate labels for the forwarding equivalence class.

Step S202: When the label request message of the upstream label switching router is not met, the first notification message fed back to the upstream label switching router;

In this step, the first notification message includes a first control message of the label request message, and the first notification message is used to control the transmission of the label request message. When meeting the label of the upstream label switching router, please When requesting a message, the label is assigned to the forwarding equivalence class, and the upstream label switching router feeds back the label mapping message of the equivalence class.

In step S202, the label request message that does not satisfy the upstream label switching router includes that the forwarding equivalence class of the upstream label switching router cannot be assigned a label, and/or the forwarding equivalence class of the upstream label switching router cannot be assigned a label; The first notification message fed back by the label switching router includes: when the label cannot be allocated to all forwarding equivalence classes of the upstream label switching router, feeding back to the upstream label switching router a first control message including stopping the forwarding of all the messages of the equivalence class; When the label cannot be assigned to the forwarding equivalence class of the upstream label switching router, the first label control message including the stop of the forwarding of the equivalence class message is fed back to the upstream label switching router.

After the step S202, that is, after the transmission of the label request message after the control according to the first control message obtained by the parsing, when the downstream label switching router satisfies the label request message of the upstream label switching router, the second notification is sent to the upstream label switching router. The second notification message includes a second control message of the label request message, and determines whether the feedback includes stopping the first control message for all the messages of the forwarding equivalence class. If the feedback is sent, the sending includes restoring all forwarding equivalence classes. The second control information of the message; if there is no feedback, determine whether the first control message including stopping the message of the forwarding equivalence class is fed back, and if the feedback is over, transmitting the message including restoring the message to the forwarding equivalence class Two control information.

The first notification message may be extended to extend the first control message to an extended status value of the first notification message and/or to extend the second notification message to extend the second control message to an extension of the second notification message In the status value.

This embodiment further provides a method for controlling another label request message, as shown in FIG. 3, including the following steps:

Step S301: In the downstream on-demand label issuing mode, the upstream label switching router sends a label request message to the downstream label switching router.

Step S302: The downstream label switching router receives the label request message sent by the upstream label switching router.

Step S303: When the label request message of the upstream label switching router is not met, the downstream label switching router feeds back the first notification message to the upstream label switching router;

In this step, the first notification message includes a first control message of the label request message, and the first notification message is used to control the sending of the label request message;

Step S304: The upstream label switching router receives the first notification message fed back by the downstream label switching router, parses the first notification message, and controls the sending of the label request message after the first control message obtained by the parsing; when the label of the upstream label switching router is satisfied When requesting a message, the downstream label switching router allocates a label to the forwarding equivalence class, and feeds back the label mapping message of the equivalence class to the upstream label switching router; the upstream label switching router receives the label mapping message of the downstream label switching router feedback forwarding equivalence class .

Embodiment 3

A method for reducing a label request message in the DOD mode according to an embodiment of the present invention is described below. In this embodiment, the first notification message and the second notification message are “no route” notification messages carrying the extended status TLV, and the first notification message and the second notification message are not limited to such other messages that can be used to control the label request. The first control message and the second control message are respectively an extended state value in the first notification message and an extended state value in the second notification message. The first notification message and the second notification message may be defined as a "no route" notification message containing an extended status value. For example, the extended state TLV structure is carried in the optional parameter of the LDP notification message defined in RFC 5036, and the extended LSR is used to indicate whether the upstream LSR continues to send the label request message. The U-bit of the extended state TLV structure described in the embodiment of the present invention needs to be set to 1; the F-bit needs to be set to 0. The extended status value is a value of 4 bytes in length. For convenience of description, the value used by the extended status value herein may be defined as follows: 0x3F000001: indicating that the label request message does not need to be sent for the FEC; 0x3F000002: indicating that the label request message needs to be continuously sent for the FEC; 0x3F000003: indicating that it is not needed Continuing to send a label request message for all FECs whose next hop is the downstream LSR and has not received the label from it; 0x3F000004: indicates that all FECs that need to re-send the downstream LSR for the downstream LSR and have not received the label from it yet Tag request message. Of course, it is not limited to the definition of the above extended state value, and the value here can be defined according to the situation. After the upstream LSR sends a label request message to a certain FEC, it receives a "no route" from the downstream LSR. When the message is notified, it is judged whether there is an extended state TLV structure, and if it exists, the extended state value is continuously judged. If the value is 0x3F000001, the label request message of the FEC is not retransmitted to the downstream LSR; if the value is 0x3F000003, then the next hop is no longer the next LSR and the label has not been received yet. All FECs continue to send tag request messages. When the configuration of the downstream LSR or the route learning is changed, the label request message sent by the upstream LSR can be satisfied. The downstream LSR resends only the extended status value according to the previously sent “no route” notification message. Routing" notification message. If a "no route" notification message with an extended status value of 0x3F000003 has occurred before, a "no route" notification message with the extended status value changed to 0x3F000004 is resent. If the "no route" notification message with the extended status value of 0x3F000003 has not been sent before, then all the FECs that have satisfied the condition and have previously sent the "no route" notification message with the extended status value of 0x3F000001 resend the extended status. The value is changed to the "no route" notification message of 0x3F000002. If the upstream LSR receives the "no route" notification message retransmitted by the downstream LSR, if the extended state value is 0x3F000004, the upstream LSR starts to re-take the next hop as the downstream LSR and has not received all the labels from it. The FEC sends a label request message. If the value is 0x3F000002, the upstream LSR sends a label request message only for the FEC corresponding to the message.

The method for reducing the label request message in the DOD mode of the MPLS network in the embodiment of the present invention is coordinated by the upstream LSR and the downstream LSR.

The processing steps of the upstream LSR are as shown in Figure 4, including:

Step S401: In the DOD mode, for a specific FEC that has not obtained a label from the downstream LSR, the upstream LSR sends a label request message to the downstream LSR; and records related content of the label request message;

Step S402: When receiving the "no route" notification message replied by the downstream LSR, determine whether there is an extended state TLV structure; if the TLV structure exists, proceed to step S403, otherwise, according to the original process specified by the LDP protocol;

Step S403: Continue to judge the extended state value in the TLV structure. If the value is 0x3F000003, the label request message is no longer sent for all the FECs whose next hop is the downstream LSR and has not received the label from the downstream LSR. If the value is 0x3F000001, the subsequent LSR is no longer attached to the downstream LSR. Send a label request message for this FEC and continue processing other FECs; if the value is 0x3F000004, proceed to step S404; if the value is 0x3F000002, proceed to step S405; and if the value is a value other than 0x3F000001 to 0x3F000004 defined in the embodiment of the present invention, then it is necessary to continue to send the downstream LSR FEC tag request message.

Step S404: The upstream LSR starts to resend the label request message for all the FECs whose next hop is the downstream LSR and has not received the label from it;

Step S405: The upstream LSR sends a label request message only for the FEC corresponding to the message.

The processing of the downstream LSR is as shown in Figure 5, including:

Step S501: When the downstream LSR receives the label request message of the upstream LSR for a certain FEC, the related content of the label request message is recorded;

Step S502: determining whether the label request message of the upstream LSR is satisfied and assigning a label to the FEC; if the label is not available for the FEC corresponding to the label request message, the method further determines whether the current LDP connection is DOD mode; if it is the DOD mode, the process proceeds to step S503; otherwise, it is processed according to the original process specified by the LDP protocol;

Step S503: determining whether the downstream LSR cannot allocate the label and the label of the notification label and the FEC to the FEC of the LSR for the next hop of the upstream LSR; if yes, proceed to step S504; otherwise, perform the process of step S505;

Step S504: Send a “No Route” notification message carrying the extended status TLV to the upstream LSR. The U-bit of the extended status TLV is set to 1, the F-bit is set to 0, and the extended status value is set to 0x3F000003. Then, the process proceeds to step S506. ;

Step S505: Send a "No Route" notification message carrying the extended state TLV to the upstream LSR; wherein, the U-bit of the extended state TLV is set to 1, the F-bit is set to 0, and the extended state value is set to 0x3F000001;

When the configuration of the downstream LSR or the route learning changes, the label request message sent by the upstream LSR can be resent, and the "no route" notification message with different extended state values is resent; if the extended status value is 0x3F000003 If there is no route notification message, the "no route" notification message with the extended status value changed to 0x3F000004 is resent. If the downstream LSR has not sent a "no route" notification message with an extended status value of 0x3F000003, then the condition has been met and the extended status value of 0x3F000001 has been sent before. All FECs of the notification message resend the "no route" notification message with the extended status value changed to 0x3F000002.

The following is a detailed description with reference to Figures 6-9:

As shown in Figure 6, the arrow indicates an indication of the next hop direction of all FECs on each LSR. For a certain FEC, two LSPs are formed between the two LSRs, R1 and R6, which are LSP1: R1->R2->R4->R6 and LSP2: R1->R3->R5->R6. The label distribution mode between R1 and R2 and R3 is DOD mode, and R2 and R3 are both downstream devices of the R1 device. Normally, the data traffic corresponding to the FEC is forwarded on LSP1 and LSP2. After the R4 node fails, R2 can be revoked as the label of all FECs allocated by R1 to prevent the quantity traffic from being forwarded on the LSP1 path that has failed. Before the R4 node is troubleshooting, if the current protocol stipulates, R1 needs to send a label request message to R2 for all FECs whose next hop is R2 but has not yet obtained a label from it.

The implementation of the technical solution on R1 and R2 will be further described in detail below with reference to the accompanying drawings:

As shown in Figure 7, after receiving the label request message, the upstream LSR receives the response of the downstream LSR replying to the "no route" notification message, including the following steps:

In step S701, R1, which is the upstream LSR, sends a label request message of a certain FEC to R2 downstream thereof. After waiting for the reply information of R2, the process proceeds to step S702.

As shown in FIG. 8, in step S801, after receiving the label request message sent by R1, R2 records the related content of the message; in step S802, it is determined that the label request message of the R1 cannot be satisfied; in step S803, it is determined that the current The LDP connection is in the DOD mode; and in step S804, it is determined that R2 has been unable to assign a label to the FEC of the LSR for all the next hops on the R1; then, in step S805, the "no route carrying the extended status TLV is sent to the R1. The notification message has an extended status value of 0x3F000003. If it is determined in step S803 that the current LDP connection is not the DOD mode, step S807 is performed to process according to the flow specified by the label distribution protocol. If the result of the determination is no at step 804, a "no route" notification message carrying the extended status TLV is sent to R1 with an extended status value of 0x3F000001.

Step S702, R1 receives R2 reply "no route" notification message, after determining that the received "no route" notification message contains the extended state TLV, proceeds to step S703;

Step S703, R1 determines that the extended state value in the extended state TLV belongs to the scope defined by the embodiment of the present invention, proceeds to step S704;

Step S704, after determining that the extended state value is 0x3F000003, proceeds to step S705; after determining that the extended state value is 0x3F000001, proceeds to step S706;

In step S705, R1 no longer sends a label request message for all FECs whose next hop is R2, and the process ends.

In step S706, R1 does not resend the label request message of the FEC to R2, and the process ends.

As shown in Figure 9, after the R4 node is faulty, R2 finds that the LSPs corresponding to R1->R2->R4->R6 can be restored for these FECs, and only the "no route" notification with different extended state values is resent. The message includes the following steps:

Step S901, after confirming that R4 is restored, R2 can satisfy the label request message sent by the previous upstream LSR, and proceeds to step S902;

Step S902, if R2 determines that the "no route" notification message of the extended state value 0x3F000003 has been sent before, proceeds to step S903; if R2 determines that the "no route" notification message of the extended state value 0x3F000001 has been previously sent, proceeds to step S904;

In step S903, R2 resends the "no route" notification message whose extension status value is changed to 0x3F000004 to R1, and ends the flow.

Step S904, the FEC resends the "no route" notification message whose extension state value is changed to 0x3F000002 for the FEC that has satisfied the condition and has previously sent the "no route" notification message of the extended state value 0x3F000001, and ends the flow.

As shown in Figure 10, after receiving the "no route" notification message with the extended status TLV sent by R2, R1 restarts sending the label request message to R2, including the following steps:

Step S1001, R1 re-receives the "no route" notification message containing the extended state TLV sent by R2, proceeds to step S1002;

Step S1002, if R1 determines that the extended state value is 0x3F000004, proceeds to step S1003; if R1 determines that the extended state value is 0x3F000001, proceeds to step S1004;

In step S1003, R1 starts to resend the label request message for all FECs whose next hop is R2 and has not received the label binding from the same, and the process ends.

In step S1004, R1 sends a label request message to the FEC corresponding to the message, and the process ends.

Embodiment 4

The present embodiment provides an upstream label switching router 1101. As shown in FIG. 11, the label request sending module 1111 and the notification message receiving module 1112 are provided. The label request sending module 1111 is configured to send a label request message to the downstream label switching router 1201. The label request message includes an identifier of a forwarding equivalence class, and the label request message is used by the downstream label switching router 1201 to allocate a label for the forwarding equivalence class; when the downstream label switching router 1201 does not satisfy the label request message of the upstream label switching router 1101, the notification is notified. The message receiving module 1112 is configured to: receive a first notification message fed back by the downstream label switching router 1201, where the first notification message includes a first control message of the label request message, the first notification message is used to control the sending of the label request message, and the notification message is received. The module 1112 is further configured to: parse the first notification message, and notify the label request sending module 1111 to send the label request message according to the parsed first control message.

The first control message includes stopping the message to the forwarding equivalence class, and/or stopping the message for all forwarding equivalence classes; the notification message receiving module 1112 is further configured to: if the parsing is to stop forwarding the equivalence class message, The notification tag request sending module 1111 stops sending the tag request message to the forwarding equivalence class; if the parsing is to stop the message of all forwarding equivalence classes, the notification tag request sending module 1111 stops sending the tag request message to all forwarding equivalence classes.

After the notification message receiving module 1112 notifies the label request message after the label request sending module 1111 controls the first control message obtained by the parsing, the downstream label switching router 1201 satisfies the label request message of the upstream label switching router 1101, and notifies the information. The receiving module is further configured to: receive a second notification message sent by the downstream label switching router 1201, where the second notification message includes a second control message of the label request message, where the second control message includes restoring the message to the forwarding equivalence class, and/or Recovering the message for all forwarding equivalence classes; the notification message receiving module 1112 is further configured to: parse the second notification message, and if the parsing is to restore the forwarding equivalence class, the notification tag request sending module 1111 re-orients the forwarding The class sends a tag request message; if the parsing is to recover all the messages of the forwarding equivalence class, the notification tag request sending module 1111 resends the tag request message to all forwarding equivalence classes.

The first control message is a message extended to an extended status value of the first notification message, and/or a second The control message is a message that is extended to the extended status value of the second notification message.

The present embodiment provides a downstream label switching router 1201. As shown in FIG. 12, the label request receiving module 1211 and the notification message sending and receiving module 1212 are provided. The label request receiving module 1211 is configured to receive the label request sent by the upstream label switching router 1101. The message request message includes an identifier of a forwarding equivalence class, and the tag request message is used to allocate a tag to the forwarding equivalence class; when the tag request message of the upstream label switching router 1101 is not satisfied, the notification message sending and receiving module 1212 is configured to: The first notification message fed back to the upstream label switching router 1101, the first notification message includes a first control message of the label request message, and the first notification message is used to control the sending of the label request message.

The label request message that does not satisfy the upstream label switching router 1101 includes that the label cannot be assigned to all forwarding equivalence classes of the upstream label switching router 1101, and/or the label cannot be assigned to the forwarding equivalence class of the upstream label switching router 1101; The module 1212 is further configured to: when the label cannot be assigned to all forwarding equivalence classes of the upstream label switching router 1101, feed back to the upstream label switching router 1101 a first control message including stopping the forwarding of all the messages of the equivalence class; When the forwarding equivalence class of the upstream label switching router 1101 allocates a label, the upstream label switching router 1101 feeds back a first control message including stopping the forwarding of the equivalence class message.

After the first notification message fed back to the upstream label switching router, when the downstream label switching router 1201 meets the label request message of the upstream label switching router 1101, the notification message sending and receiving module 1212 is further configured to: forward the label switching router 1101 Sending a second notification message, where the second notification message includes a second control message of the label request message, determining whether the feedback includes stopping the first control message for all the messages of the forwarding equivalence class, and if the feedback is Forwarding the second control information of the message of the equivalence class; if there is no feedback, determining whether the first control message including stopping the message of the forwarding equivalence class is fed back, if the feedback is over, sending the retrieving pair forwarding equivalence class The second control information of the message.

Extending the first notification message, extending the first control message to an extended state value of the first notification message, and/or extending the second notification message to extend the second control message to an extended state of the second notification message In the value.

This embodiment provides a control system for a label request message, as shown in FIG. 13, including an upstream label switching router 1101 and a downstream label switching router 1201: an upstream label switching router 1101. The method is configured to: send a label request message to the downstream label switching router 1201, the label request message includes an identifier of a forwarding equivalence class, the label request message is used by the downstream label switching router 1201 to allocate a label for the forwarding equivalence class; and the downstream label switching router 1201 sets The receiving the label request message sent by the upstream label switching router 1101; when the label request message of the upstream label switching router 1101 is not satisfied, the downstream label switching router 1201 is further configured to: the first notification message fed back to the upstream label switching router 1101, The first notification message includes a first control message of the label request message, and the first notification message is used to control the sending of the label request message. The upstream label switching router 1101 is further configured to: receive the first notification message fed back by the downstream label switching router 1201, and analyze The first notification message controls the sending of the label request message after the first control message obtained by the parsing.

One of ordinary skill in the art will appreciate that all or a portion of the steps of the above-described embodiments can be implemented using a computer program flow, which can be stored in a computer readable storage medium, such as on a corresponding hardware platform (eg, The system, device, device, device, etc. are executed, and when executed, include one or a combination of the steps of the method embodiments.

Alternatively, all or part of the steps of the above embodiments may also be implemented by using an integrated circuit. These steps may be separately fabricated into individual integrated circuit modules, or multiple modules or steps may be fabricated into a single integrated circuit module. achieve.

The devices/function modules/functional units in the above embodiments may be implemented by a general-purpose computing device, which may be centralized on a single computing device or distributed over a network of multiple computing devices.

When the device/function module/functional unit in the above embodiment is implemented in the form of a software function module and sold or used as a stand-alone product, it can be stored in a computer readable storage medium. The above mentioned computer readable storage medium may be a read only memory, a magnetic disk or an optical disk or the like.

Industrial applicability

When the downstream label switching router fails to meet the label request message of the upstream label switching router, the embodiment of the present invention stops sending the label request message to the downstream label switching router by using the first notification message that is fed back, which can prevent the upstream label from repeatedly sending the label request message. Reduce the system's resource consumption in processing these messages, save resources, and improve system processing performance.

Claims

A method for controlling a label request message includes:

Sending a label request message to the downstream label switching router in a downstream on-demand label issuing manner, the label request message includes an identifier of a forwarding equivalence class, and the label request message is used by the downstream label switching router. Forward the equivalence class to assign labels;

Receiving, by the downstream label switching router, a first notification message that is fed back by the downstream label switching router, where the first notification message includes a first control message of the label request message, where the first label switching router does not meet the label request message of the upstream label switching router. A notification message is used to control the sending of the label request message;

The first notification message is parsed, and the subsequent transmission of the label request message is controlled according to the parsed first control message.
The method for controlling a tag request message according to claim 1, wherein the first control message comprises stopping a message for the forwarding equivalence class, and/or stopping a message for all forwarding equivalence classes; The sending of the label request message after the control message is controlled comprises: if the parsing is to stop the forwarding equivalence class, stopping sending the label request message to the forwarding equivalence class; if the parsing is stopped, All messages forwarding the equivalence class stop sending tag request messages to all forwarding equivalence classes.
The method for controlling a tag request message according to claim 2, wherein after the downstream tag switching router satisfies the tag request message of the upstream tag switching router after the transmission of the tag request message after the control according to the first control message obtained by the parsing Receiving, by the downstream label switching router, a second notification message, where the second notification message includes a second control message of the label request message, where the second control message includes restoring the message to the forwarding equivalence class, and And resuming the message for all forwarding equivalence classes; parsing the second notification message, if the parsing is to recover the message of the forwarding equivalence class, resending the tag request message to the forwarding equivalence class; The parsing result is to restore all the forwarding equivalence class messages, and then re-send the label request message to all forwarding equivalence classes.
The method for controlling a tag request message according to any one of claims 1 to 3, wherein the first control message is a message extended to an extended status value of the first notification message, and/or The second control message is a message that is extended to an extended status value of the second notification message.
A method for controlling a label request message includes:

Receiving, in a downstream on-demand label issuing manner, a label request message sent by an upstream label switching router, where the label request message includes an identifier of a forwarding equivalence class, and the label request message is used to allocate the forwarding equivalence class. label;

When the label request message of the upstream label switching router is not satisfied, the first notification message fed back to the upstream label switching router, the first notification message includes a first control message of the label request message, where the first notification message is used The control tag requests the sending of a message.
The method for controlling a label request message according to claim 5, wherein the label request message that does not satisfy the upstream label switching router includes failing to allocate labels for all forwarding equivalence classes of the upstream label switching router, and/or cannot Allocating a label for the forwarding equivalence class of the upstream label switching router; the first notification message fed back to the upstream label switching router includes: failing to allocate all forwarding equivalence classes for the upstream label switching router And transmitting, to the upstream label switching router, a first control message including stopping the forwarding of the message of the forwarding equivalence class; when the label cannot be allocated for the forwarding equivalence class of the upstream label switching router, The upstream label switching router feedback includes a first control message that stops the message of the forwarding equivalence class.
The method for controlling a tag request message according to claim 6, wherein, after the first notification message fed back to the upstream label switching router, when the downstream label switching router satisfies the label request message of the upstream label switching router, The upstream label switching router sends a second notification message, where the second notification message includes a second control message of the label request message, and determines whether the feedback includes stopping the first control message for all the messages of the forwarding equivalence class, if the feedback is Transmitting, by the second control information, including recovering the message for all forwarding equivalence classes; if not, determining whether the first control message including stopping the message of the forwarding equivalence class is fed back, if the feedback is And transmitting second control information including restoring the message to the forwarding equivalence class.
The method for controlling a tag request message according to any one of claims 5 to 7, wherein the first notification message is extended to extend the first control message to an extended state value of the first notification message And/or expanding the second notification message to extend the second control message to an extended status value of the second notification message.
A method for controlling a label request message includes:

In the downstream on-demand label issuing mode, the upstream label switching router sends a label request message to the downstream label switching router, and the label request message includes an identifier of a forwarding equivalence class, and the label request message is used for the downstream label switching. The router allocates a label to the forwarding equivalence class;

Receiving, by the downstream label switching router, a label request message sent by the upstream label switching router;

When the label request message of the upstream label switching router is not satisfied, the downstream label switching router feeds back a first notification message to the upstream label switching router, where the first notification message includes a first control message of the label request message. The first notification message is used to control sending of the label request message;

The upstream label switching router receives the first notification message fed back by the downstream label switching router, parses the first notification message, and controls transmission of the label request message after the first control message obtained by the parsing.
An upstream label switching router includes a label request sending module and a notification message receiving module:

The label request sending module is configured to send a label request message to the downstream label switching router in a downstream on-demand label issuing manner, where the label request message includes an identifier of a forwarding equivalence class, and the label request message is used for The downstream label switching router allocates a label to the forwarding equivalence class;

The notification message receiving module is configured to: when the downstream label switching router does not satisfy the label request message of the upstream label switching router, receive the first notification message fed back by the downstream label switching router, where the first notification message includes a label request message The first control message, the first notification message is used to control the sending of the label request message; and the first notification message is parsed, and the label after the label request sending module is notified according to the first control message obtained by the parsing The request message is sent.
The upstream label switching router of claim 10, wherein said first control message comprises stopping a message for said forwarding equivalence class, and/or stopping a message for all forwarding equivalence classes; said notification message receiving The module is set to: if the notification message receiving module parses Stopping the message of the forwarding equivalence class, notifying the tag request sending module to stop sending a tag request message to the forwarding equivalence class; if the parsing is to stop all forwarding equivalence classes, the notification station The tag request sending module stops sending a tag request message to all forwarding equivalence classes.
A downstream label switching router includes a label request receiving module and a notification message sending module:

The tag request receiving module is configured to: receive, in a downstream on-demand label issuing mode, a label request message sent by an upstream label switching router, where the label request message includes an identifier of a forwarding equivalence class, and the label request message is used by the label request message. Allocating a label for the forwarding equivalence class;

When the label request message of the upstream label switching router is not satisfied, the notification message sending module is configured to: a first notification message fed back to the upstream label switching router, where the first notification message includes a first control of the label request message The message, the first notification message is used to control the sending of the label request message.
The downstream label switching router of claim 12, wherein the label request message that does not satisfy the upstream label switching router includes failing to allocate labels for all forwarding equivalence classes of the upstream label switching router, and/or cannot The forwarding equivalence class allocation label of the upstream label switching router; the notification message sending module is further configured to: when the label cannot be allocated for all forwarding equivalence classes of the upstream label switching router, exchange the label with the upstream label The router feedback includes a first control message that stops all messages forwarding the equivalence class; when the label cannot be assigned to the forwarding equivalence class of the upstream label switching router, the feedback to the upstream label switching router includes stopping the A first control message for forwarding a message of an equivalence class.
A control system for tag request messages, including an upstream label switching router and a downstream label switching router:

The upstream label switching router is configured to send a label request message to the downstream label switching router in a downstream on-demand label issuing manner, where the label request message includes an identifier of a forwarding equivalence class, and the label request message is used for The downstream label switching router allocates a label to the forwarding equivalence class;

The downstream label switching router is configured to: receive the sending by the upstream label switching router Tag request message;

When the label request message of the upstream label switching router is not satisfied, the downstream label switching router is further configured to: a first notification message fed back to the upstream label switching router, where the first notification message includes a label request message a first control message, where the first notification message is used to control transmission of a label request message;

The upstream label switching router is further configured to: receive a first notification message fed back by the downstream label switching router, parse the first notification message, and control transmission of the label request message after the first control message obtained by the parsing.
A computer readable storage medium storing computer executable instructions for performing the method of any of claims 1-9.