WO2014059570A1

WO2014059570A1 - Method, device and system for establishing label switched path

Info

Publication number: WO2014059570A1
Application number: PCT/CN2012/082939
Authority: WO
Inventors: 饶国义; 贺志国
Original assignee: 华为技术有限公司
Priority date: 2012-10-15
Filing date: 2012-10-15
Publication date: 2014-04-24
Also published as: CN103238299A; CN103238299B

Abstract

Provided are a method, device and system, applied in the field of communication, for pre-assigning a label and establishing a label switched path. The method specifically comprises: each node of a network assigns the label sets according to the node identification of the neighboring node of said node, wherein the pre-assigned label sets can be used to establish the label switched path. With the present invention to establish the label switched path in the network pre-assigned the label sets, when a node establishes a forward cross connection, said node does not need to request the downstream node to assign a label but can establish a label switched path using the Path process, through which the access time of business or the recovery time of interrupted business is reduced and the user experience is improved.

Description

Method, device and system for establishing label switching path

The present invention relates to the field of communications technologies, and in particular, to a method, device and system for pre-allocating tags and establishing label switching paths.

Background technique

With the rapid development of the Internet, users are increasingly demanding bandwidth. The tremendous pressure from ever-increasing bandwidth forces operators to choose packet-switched networks that use statistical multiplexing to maximize transmission efficiency.

Multi-protocol label switching (MPLS) is a kind of multi-layer switching technology based on packet switching. When a service request is received, a label switched path (LSP) needs to be established. The new LSP establishment time in the prior art is one of the important reasons for limiting the service access speed. At the same time, in the MPLS network, it is important to ensure the reliability of the transmission path. When the transmission path fails, the transmission path needs to be restored as quickly as possible to reduce the interruption time of the service. When the LSP transmission failure occurs in the network, the main method for recovering the service transmission is to establish a new LSP through the signaling protocol, which is used for rerouting the faulty transmission path. During the entire LSP fault recovery process, the new LSP establishment time often accounts for the majority of the LSP fault recovery time. Improving the recovery LSP establishment speed is the key to improving the LSP fault recovery process.

In an MPLS switching network, the direction of traffic sent from the ingress node to the egress node is called forward, and the cross-connection for forward traffic is called LSP forward cross-connection. Similarly, The direction of traffic sent from the last node to the head node is called reverse, and the cross-connection for reverse traffic is called LSP reverse cross-connection. For the node through which the LSP passes, the neighboring node in the direction of the LSP head node is referred to as the upstream node, and the neighboring node in the direction of the last node is referred to as the downstream node. In the prior art, the steps of establishing a new LSP mainly include: establishing a reverse cross-connection of an LSP in a Path message sent by a first node to a last node; establishing a LSP in a process of sending a RESV message to a first node by a last node Connect to the cross. If the created LSP is a unidirectional positive direction LSP, each node sends a forward label to the downstream node to establish a forward cross-connection, and cannot directly perform the forward direction. The establishment of the cross-connection; in the process of sending the RESV message to the first node, each node performs the forward label assignment and the forward cross-connection establishment; if the created LSP is a bidirectional LSP, the PATH of the last node is sent from the first node. During the message process, the reverse cross-connection is established on each node, and the downstream node is requested to allocate a forward label; in the process of sending the RESV message to the first node, the nodes perform forward label assignment and forward crossover. The connection is established.

Establishing a new MPLS LSP or rerouting MPLS LSP needs to go through the Path process and the RESV process. The cross-connection establishment time of the end-to-end MPLS LSP is the PATH process time plus the RESV process time, resulting in slow service access or service interruption time. Too long, affecting the user experience. An important reason for causing these problems is that the existing label allocation mechanism is imperfect. For each time a new LSP or a reroute LSP is established, a Path message is required to be hop-by-hop on each node, and then a Resv message is sent in reverse. It is requested to allocate a forward label hop by hop to establish a forward cross connection, which results in an LSP establishment time being too long. Summary of the invention

An embodiment of the present invention provides a method, a device, and a system for establishing an LSP, in particular, a first method according to an embodiment of the present invention, in order to overcome the disadvantages of the LSP being established in the prior art because the label allocation mechanism is imperfect. In an aspect, a method for establishing a label switched path LSP is provided, where: the first node calculates an LSP from the first node to the second node according to a network topology of the multi-protocol label switching network, to obtain an LSP of the LSP. a path information; the first node establishes a forward cross-connection by using a first forward outgoing label and a first forward outgoing interface index of the first node in the LSP path information; The outgoing label is an unused label in the label set pre-assigned to the first node by the downstream node adjacent to the first node on the LSP; the downstream node adjacent to the first node is in the An adjacent node downstream of the first node in the forward direction of the LSP; a forward direction along the LSP from the first node to the second node, along the LSP Transmitting the second node to the first node is reversed; the first node sends a first Path message to a downstream node that is adjacent to the first node, where the first Path message carries the LSP The LSP path information of each node downstream of the first node and the first forward outgoing label in the forward direction, where the first Path message is used in the forward direction of the LSP. Each node downstream of a node establishes a positive cross-connection.

In a first possible implementation manner of the first aspect, optionally, after the forward cross connection of the first node is established, and the forward cross connection of the second node is established, Switching the forward traffic to the LSP; or, after receiving the continuity check CCM packet from the second node, the first node switches the forward traffic to the LSP, where the CCM report The message carries information for confirming that the second node has established a positive cross-connection.

In a second possible implementation manner of the first aspect, further, the first node uses a reverse ingress label of the first node and a reverse entry of the first node in the LSP path information The interface index establishes a reverse cross-connection, and the reverse-entry label of the first node is an unused label that is determined by the first node from the label resource pool of the local node; The first path message is further configured to establish a reverse cross-connection at each node downstream of the first node in a forward direction of the LSP. In a third possible implementation manner of the first aspect, further, calculating, by the first node, an LSP from the first node to the second node according to a network topology of the multi-protocol label switching network Before obtaining the LSP path information of the LSP, the first node obtains the label set from a downstream node adjacent to the first node, where the label set is a downstream adjacent to the first node. a set of labels available to the first node determined by the node; and storing the obtained set of labels.

In the method for establishing an LSP according to the embodiment of the present invention, the label resource between the nodes in the MPLS network is allocated in advance before the LSP is established, and the first node can establish a forward cross connection in the Path process, and the first node in the prior art. Compared with the method that the Path process and the Resv process are required to establish an LSP forward cross connection, the LSP establishment time is shortened. At the same time, the forward traffic can be switched after the forward cross-connection is established on the first node to ensure that the new LSP can be used for bearer services. The method disclosed in the embodiment of the present invention shortens the time for establishing an LSP, thereby reducing service access time or service recovery time and improving user experience.

According to a second aspect of the present invention, a method for establishing a label switched path LSP is provided. The LSP is an LSP from a first node to a second node, and the third node is the first node on the LSP. And an intermediate node between the second node and the second node is forward along the LSP, and the LSP is reversed from the second node to the first node, Specifically, the third node receives a second Path message sent by an upstream node adjacent to the LSP path, where the adjacent upstream node is in the forward direction of the LSP. a neighboring node upstream of the three nodes; the third node acquires the path information carried in the second Path message received by the third node and the first forward outgoing label of the upstream node adjacent thereto, and the LSP is positive An unused label in a label set assigned thereto to a downstream node adjacent thereto is used as a second forward outgoing label, and the first forward outgoing label is used as a second forward incoming label, according to the first Two forward tags The second forward ingress label and the obtained path information establish a forward cross connection; the third node sends a third Path message to the downstream node that is adjacent thereto, where the third Path message carries The LSP path information of each node downstream of the third node in the forward direction of the LSP and the second forward outgoing label, where the third Path message is used in the forward direction of the LSP. Each node downstream of the third node establishes a positive cross-connection.

In a first possible implementation manner of the second aspect, the third node acquires a first reverse incoming label of the upstream node that is adjacent to the second Path message that is received by the third node, The first reverse entry label is used as the second reverse outgoing label of the third node, and an unused label determined by the third node from the label resource pool of the local node is used as the third node. And the reverse inbound interface index and the reverse outbound interface index are established according to the second reverse outgoing label, the second reverse incoming label, and the third node in the LSP path information. a reverse cross-connect; the third Path message further carries the second reverse-ingress label, where the third Path message is further used to be downstream of the third node in the forward direction of the LSP. Each node establishes a reverse cross-connection.

In a second possible implementation manner of the second aspect, further, the first node sends Before establishing the LSP, the third node determines, in the label resource pool that can be used by the node, the label set that can be used by the upstream node adjacent to the adjacent upstream node, and An upstream node adjacent thereto sends a message to announce the determined set of labels.

In the method for establishing an LSP according to the embodiment of the present invention, the label resource between the nodes in the MPLS network is allocated in advance before the LSP is established, and the intermediate node can establish a forward cross connection in the Path process, and the intermediate node in the prior art. Compared with the method that the Path process and the Resv process are required to establish an LSP forward cross connection, the LSP establishment time is shortened. The method disclosed in the embodiment of the present invention shortens the time for establishing an LSP, thereby reducing service access time or service recovery time and improving user experience.

According to a third aspect of the present invention, a packet transport network device is provided, including: a processing module, configured to establish a forward cross-connection by using the label switched path LSP path information obtained by the label switching path and the first label from the storage module, The first label is an unused label of a label set pre-assigned to the packet transport network device by a downstream packet transport network device adjacent to the packet transport network device on the LSP path, the downstream The packet transport network device is a packet transport network device that is downstream of the packet transport network device in the forward direction of the LSP path, and a generating module is configured to generate a Path message, where the Path message carries each of the downstream packet transport networks. The LSP path information of the device and the first label, the destination address of the Path message is an address of a downstream packet transport network device adjacent to the packet transport network device on the LSP path, and a sending module, configured to send The message generated by the generation module.

In a first possible implementation manner of the third aspect, the processing module is further configured to: after the forward cross connection establishment of the packet transport network device, the last packet transport network device in the forward direction of the LSP Before the forward cross-connection is established, the forward traffic is switched to the LSP; or the processing module is further configured to: after receiving the continuity check CCM message sent by the last packet transport network device, Switching to the LSP, the CCM message carries information for confirming that the last packet transport network device has established a forward cross-connection.

In a second possible implementation manner of the third aspect, the processing module is further configured to establish a reverse cross-connection by using the obtained LSP path information and the second label from the storage module as a reverse incoming label, where The second label is an unused label in the label resource pool of the packet transport network device itself. The generating module is further configured to carry the second label in the Path message.

The packet transport network device disclosed in the embodiment of the present invention allocates the label resource between the packet transport network devices in the MPLS network in advance before establishing the LSP, so that the allocated label can be directly utilized when the new LSP is established without re-allocation. The forward cross-connection can be established in the Path process. Compared with the prior art method that requires the Path process and the Resv process to establish an LSP forward cross-connection, the time for establishing a new LSP is reduced. At the same time, the packet transmission network device at the LSP head node establishes a forward cross-connection, that is, the forward traffic is switched, and the new LSP can be used to carry the service for the first time, which shortens the service access time or service recovery time. , improved user experience. According to a fourth aspect of the present invention, a packet transport network device is provided, including: a receiving module, configured to receive a message; a parsing module, configured to parse a message received by the receiving module; and a processing module, configured to: The forward outgoing label of the upstream packet transport network device adjacent to the packet transport network device of the parsing module is used as a forward inbound label of the packet transport network device, and the first label from the storage module is used as the a forward outgoing label of the packet transport network device, based on the forward incoming label of the packet transport network device, the forward outgoing label of the packet transport network device, and the path information of the label switched path LSP from the parsing module To a cross-connect, wherein the packet transport network device is a packet transport network device on the LSP, and the first tag is a downstream packet transport network device adjacent to the packet transport network device on the LSP path Pre-assigned to an unused tag in the set of labels of the packet transport network device, the downstream packet transport network device being at the LSP a packet transport network device downstream of the packet transport network device in direction; further configured to determine, according to a device identifier from the storage module or from the parsing module, a label set usable by the packet transport network device having the device identifier The device identifier is a device identifier of an upstream packet transport network device that is adjacent to the packet transport network device in the forward direction of the LSP. The generating module is configured to generate a Path message, where the Path message carries An LSP path information of each packet transport network device downstream of the packet transport network device on the LSP, and the first label, where the destination address of the Path message is in the forward direction of the LSP and the packet transport network device The address of the adjacent downstream packet transport network device is further configured to generate an advertisement message according to the device identifier and the label set determined by the processing module, where the advertisement message carries the device identifier, and the packet transport network device itself The device identifier and the label set determined by the processing module, where the destination address of the advertisement message is in the forward direction of the LSP The packet transfer network device adjacent upstream packet transmission network equipment; transmitting means for transmitting a message generated by the generating module.

In a first possible implementation manner of the fourth aspect, the processing module is further configured to: use a reverse ingress label of an upstream packet transport network device adjacent to the packet transport network device from the parsing module a reverse outgoing label of the packet transport network device, using an unused label determined by the packet transport network device from its own label resource pool as a reverse incoming label of the packet transport network device, and transmitting by using the packet a reverse outgoing label of the network device, a reverse incoming label of the packet transport network device, and the LSP path information establishes a reverse cross-connection; the generating module is further configured to reverse the incoming packet network device The tag is carried in the Path message.

The packet transport network device disclosed in the embodiment of the present invention allocates the label resource between the packet transport network devices in the MPLS network in advance before establishing the LSP, so that the allocated label can be directly utilized when the new LSP is established without re-allocation. The forward cross-connection can be established in the Path process. Compared with the previous method in which the Path process and the Resv process are required to establish an LSP forward cross-connection, the time for establishing a new LSP is reduced, and the service access time is shortened. Business recovery time improves the user experience.

According to a fifth aspect of the embodiments of the present invention, a network system is provided, including: the network system includes at least a first packet transport network device, a second packet transport network device, and a third packet transport network device, the first packet The transport network device and the second packet transport network device transmit through the third packet The network device is connected; the direction from the first packet transport network device to the second packet transport network device is forward, and the direction from the second packet transport network device to the first packet transport network device is reversed; a first packet transport network device, configured to calculate an LSP from the first packet transport network device to the second packet transport network device according to a network topology of the network system, to obtain path information of the LSP, a forward outgoing label and the path information establish a forward cross connection, and send a first Path message to a downstream packet transport network device adjacent to the first packet transport network device in a forward direction of the LSP, where a forward outgoing label is an unused label of a set of labels pre-assigned to the first packet transport network device by a downstream packet transport network device adjacent to the first packet transport network device in the forward direction of the LSP The third packet transport network device is configured to receive a second Path message sent by the upstream packet transport network device adjacent to the LSP in the forward direction, and the obtained second path is obtained. The forward outgoing label carried in the information is used as the forward ingress label of the third packet transport network device, and the path information carried in the second Path message obtained by the third packet transport network device is used. a forward inbound label of the three packet transport network device and a forward outgoing label of the third packet transport network device establish a forward cross connect and are adjacent to the third packet transport network device in a forward direction of the LSP The downstream packet transport network device sends a third Path message, and the forward outgoing label of the third packet transport network device is a downstream packet transport network device adjacent to the third packet transport network device in the forward direction of the LSP. Pre-assigned to an unused tag in the tag set of the third packet transport network device; the second packet transport network device, configured to receive, by the upstream packet transport network device adjacent to the LSP in the forward direction a fourth Path message, and the forward outgoing label carried in the obtained fourth Path message is used as a forward ingress label of the second packet transport network device, and is transmitted by using the second packet The forward inbound label of the network device establishes a forward cross connection with the path information carried in the obtained fourth path message.

In a first possible implementation manner of the fifth aspect, optionally, the first packet transport network device is further configured to: after the forward cross connection establishment of the first packet transport network device, the second Before the forward cross-connection of the packet transport network device is established, the forward traffic is switched to the LSP; or, after receiving the continuity check CCM packet sent by the second packet transport network device, The traffic is switched to the LSP, and the CCM packet carries information that can confirm that the second packet transport network device has established a forward cross-connection.

In a second possible implementation manner of the fifth aspect, the first packet transport network device is further configured to determine that an unused label in the label resource pool of the first packet transport network device itself is a reverse ingress label of the first packet transport network device, establishing a reverse cross connection by using a reverse inbound label of the first packet transport network device and the obtained LSP path information, and transmitting the reverse packet of the first packet transport network device The reverse packet is carried in the first Path message; the third packet transport network device is further configured to: reverse the third packet transport network carried in the received second Path message, and determine An unused label in the label resource pool of the third packet transport network device itself is a reverse incoming label of the third packet transport network device, and the reverse incoming label of the third packet transport network device and the The obtained LSP path information establishes a reverse cross connection, and the first The reverse packet of the third packet transport network device is carried in the third Path message; the second packet transport network device is further configured to send the second packet transport network carried in the received fourth Path message Deviating the label, determining that an unused label in the label resource pool of the second packet transport network device itself is a reverse incoming label of the second packet transport network device, and using the second packet transport network device The reverse incoming label and the obtained LSP path information establish a reverse cross-connection.

In the network system disclosed in the embodiment of the present invention, the label resource between nodes in the MPLS network is allocated in advance before the LSP is established, and the packet transport network device in the network can establish a positive cross-connection in the Path process, and the prior art Compared with the method in which the first node needs the Path process and the Resv process to establish an LSP forward cross connection, the time for establishing the LSP is shortened. At the same time, the packet transport network device at the head node on the LSP can switch the forward traffic after establishing the forward cross-connection, and the packet transport network device at the last node switches the reverse traffic after the reverse cross-connection. The new LSP can be used to carry the service for the first time. The method disclosed in the embodiment of the present invention shortens the time for establishing an LSP, thereby reducing service access time or service recovery time and improving user experience.

DRAWINGS

In order to more clearly illustrate the invention and related embodiments, the following figures are provided:

1 is a flowchart of a method for pre-allocating tags between nodes according to Embodiment 1 of the present invention;

2 is a flowchart of a method for establishing a label switching path according to Embodiment 2 of the present invention;

3 is a flowchart of a method for establishing a label switching path according to Embodiment 3 of the present invention;

4 is a structural diagram of a packet transport network device according to Embodiment 4 of the present invention;

5 is a structural diagram of a packet transport network device according to Embodiment 5 of the present invention;

FIG. 6 is a structural diagram of a network device according to Embodiment 6 of the present invention.

Specific embodiment

In order to make the objects, the technical solutions and the advantages of the present invention more comprehensible, the present invention will be further described in detail below with reference to the embodiments and drawings. The illustrative embodiments of the present invention and the description thereof are intended to be illustrative of the invention, and are not intended to limit the invention.

Embodiment 1 The embodiment of the present invention provides a method for pre-allocating labels between nodes before establishing an LSP. As shown in FIG. 1, the method includes:

Step S101: Before establishing the LSP, the first node determines, according to the node identifier of each neighbor node, a label set that can be used by each neighbor node for each neighbor node, where each neighbor node is a node adjacent to the first node. , the set of tags includes one or more tags. Each tag can be a corresponding number, such as tags can be 100, 101, 102, and the like. The first node is a packet transmission in the MPLS network. Packet transmission network (PTN) equipment refers to equipment that uses packet switching technology to transmit data, such as label switching routers (LSRs) and label switching edge routers (labe l). Swi tching edge router ( LER ), switch, packet switching device, packet transport network device, etc., such a packet transport network device is called a node, and other nodes adjacent to it are neighbor nodes of the node. Optionally, if the first node does not know the node identifier of each neighbor node, the internal gateway protocol (IGP) message may be used to interact with the network topology information to obtain the node identifier of the neighbor node. Optionally, the node identifier may be a device identifier of the node device, or may be an Internet Protocol address of the node, or may be an integer. In short, the first node may be used to identify a neighbor node adjacent to the first node. Other identifiers that may be used by the first node to identify different neighbor nodes adjacent thereto. After obtaining the node identifier of the neighboring node, the first node allocates an unused and idle label set from the label range supported by the node as a label set pre-allocated to the neighbor, and establishes a corresponding entry to save each neighbor node. , the set of labels assigned to it, and the correspondence between the two. The labels in the set of labels assigned to the neighbor nodes are no longer used for the establishment of cross-connections of other neighbor nodes until they are released for recycling. Optionally, the assigned tag sets or tags may be marked as allocated, and other neighbor nodes do not use the tags in the tag set when establishing the cross-connection, and are marked as the assigned tag set before being released for recycling. Or the label can only be used to establish a service connection between the neighbor node assigned to the label set or the label and the first node.

Step S1 02, the first node sends a message to each neighbor node, and the message sent to any one of the neighbor nodes carries the node identifier of the neighbor node, the node identifier of the first node, and the first The set of labels that the node assigns to the neighbor node. The first node generates a message according to the above-mentioned established entry or directly according to the allocation of the label set by the first node to the neighboring node, and the message may be an extended IGP protocol message, or an extended Ethernet packet, or It is another message type, as long as it can be used for carrying the node identifier of the destination neighbor node, the node identifier of the first node, and the label set allocated by the first node to the destination neighbor node. The destination address of the message may be a unicast address, and the sent content may be a node identifier of the destination neighbor node, a node identifier of the first node, and a label set allocated by the first node to the destination neighbor node, and the sent content may also be a table. Item, the entry includes the node identifier of the first node, the node identifier of all the neighbor nodes of the first node, and the label set allocated by the first node to the neighbor nodes, and the neighbor node that receives the message can identify by itself Find the set of labels assigned to yourself in the table entry. The message may also be a broadcast address, and the sent content may be the above-mentioned node identifier including the first node, the node identifier of all the neighbor nodes of the first node, and the label set of the label set allocated by the first node to the neighbor nodes. Thus, the first node can have its neighbor nodes get the set of available labels that they have assigned to them. Optionally, after the neighbor node receives and saves the first node, the label set allocated by the first node, and the corresponding relationship between the two nodes, the neighbor node may reply to the message to confirm that the message sent by the first node is received, and the label is confirmed. The assignment is complete.

Optionally, the first node may also receive the message sent by each neighbor node, and the message sent by each neighbor node carries the node identifier of the first node and the node identifier of the source node. And a label set allocated by the source node to the first node, where the source node is a node that sends the message adjacent to the first node; the first node stores a node identifier of the source node, and the source node is assigned to the first node The label set of the node and the correspondence between the node identifier of the source node and the label set assigned by the source node to the first node. Through this step, the first node can obtain the set of tags to which its neighbor nodes are assigned.

Optionally, the label set allocated by a node to its neighbor node may include multiple sub-tag sets, and may also allocate a label set multiple times to the same neighbor node. Optionally, all the nodes in the MPLS network can use the foregoing steps to implement label pre-allocation with their neighbor nodes.

Optionally, the allocated label can be reclaimed through a certain process. Specifically, if the node allocates multiple label sets to a neighbor node, it finds that all labels in a label set allocated to a neighboring node are If the tag is in the idle state, and the tag in the other tag set is not used yet, the message can be sent to the neighbor node for revocation. After receiving the confirmation message sent by the neighbor node, the tag set can be recovered.

The label pre-allocation method disclosed in the embodiment of the present invention can allocate the label resources between the nodes in the MPLS network in advance before the LSP is established, and overcomes the requirement that the LSPs must be allocated hop by hop every time a new LSP is established in the prior art. The forward label and the hop-by-hop allocation of the forward label according to the request, so that when the new LSP or the original LSP fails to be established, the re-routed LSP needs to be established, and the allocated label can be directly used without having to re-allocate each time. , greatly reducing the time for establishing a new LSP, shortening the service access time or service recovery time, and improving the user experience.

Embodiment 2: The embodiment of the present invention provides a method for establishing a label switching path LSP, where

The LSP is an LSP from the first node to the second node, and the LSP is forward from the first node to the second node along the LSP, and the LSP is from the second node to the first node. Reverse, as shown in Figure 2.

Step S201, optionally, before the first node initiates establishment of the LSP, that is, the first node calculates, according to a network topology of the multi-protocol label switching network, a path from the first node to the Before the LSP of the second node obtains the LSP path information of the LSP, the first node obtains the determined by the downstream node adjacent to the first node from a downstream node adjacent to the first node The set of tags available to the first node and stores the obtained set of tags. If the first node has stored a set of available labels to which adjacent downstream nodes on the LSP are assigned, this step may be omitted. The method of allocating the label set may be the method in the first embodiment, and will not be described again. Optionally, other nodes in the network can also use the same method to pre-allocate labels with their neighbor nodes. It should be noted that the pre-allocation label between the nodes may be the time when the network is initialized, or may be other times, but must be before the request to establish the LSP, that is, before the establishment of the LSP. That is to say, the embodiment of the present invention has already allocated the labels between the nodes before initiating the establishment of the LSP, so it is not necessary to request the downstream nodes to allocate the forward outgoing labels when establishing the LSP, and can be established in the Path process. Forward cross connection. Optionally, the pre-allocation of the label may be pre-allocating an alternate label set for each node in each existing LSP for use in a fault; or may be a virtual LSP in the network system in advance. Assign the corresponding label, and directly use when the signaling of establishing the LSP arrives. A label assigned to a virtual LSP; or all nodes in the system may assign labels to their neighbor nodes.

Step S202: The first node calculates an LSP from the first node to the second node according to the network topology of the multi-protocol label switching network, and obtains LSP path information of the LSP. The path information includes a node identifier of each node on the path, a first forward outbound interface index of the first node, a second forward inbound interface index of the second node, and an intermediate node between the first node and the second node. Forward inbound interface index and forward outbound interface index. The first node is the ingress node of the LSP, and the second node is the egress node of the LSP.

Step S203: The first node establishes a forward cross-connection by using a first forward outgoing label and a first forward outgoing interface index of the first node in the LSP path information, where the first forward outgoing label An unused label of the label set in the first node that is pre-allocated by the first node on the LSP to the first node, where a downstream node of a node refers to a forward direction of the LSP. The node in the direction behind the node. The first node determines, according to the node identifier of the adjacent downstream node of the first node included in the path information, to find a label set allocated by the downstream node to the first node, and then uses an unused label in the label set as the first Forward the label. Optionally, if the LSP is configured with the bandwidth requirement, the first node performs the resource check and the bandwidth allocation before the cross-connection is established. If the bandwidth allocation fails, the LSP fails to be established, and the process ends.

Optionally, if a bidirectional LSP is established, the first node may further establish a reverse direction by using the first reverse ingress label and the first reverse inbound interface index of the first node in the LSP path information. A cross-connect, the first reverse-entry label is an unused label allocated by the first node from a label resource pool of the node. An unused label allocated in the label resource pool of the node may be an unused label in a label set that has been pre-assigned to the adjacent downstream node of the node, or may be an unused label that is not assigned to any neighbor node. , but not the label in the label set assigned to the node by the neighboring node, nor the label in the label set that the node has assigned to other neighbor nodes, nor the adjacent downstream node assigned to the node. The label is in use. Optionally, when the LSP is established, the forward outgoing interface index used by a node to establish the cross-connection of the LSP may be the same as the reverse incoming interface index, and the reverse outgoing interface index may be forwarded to the forward interface index. The same can be said in the following embodiments, and will not be described again.

Step S204: The first node sends a Path message to a downstream node that is adjacent to the first node on the LSP, where the Path message is used to establish a positive manner on each downstream node of the first node on the LSP. Connect to the cross. The Path message causes a node other than the second node downstream of the first node on the LSP to use an unused label of its label set pre-assigned to its neighboring downstream node, adjacent thereto The path information carried in the Path message sent by the upstream node establishes a forward cross-connection with the forward outgoing label, so that the second node establishes a positive crossover by using the path information carried in the Path message sent by the neighboring upstream node and the forward outgoing label. connection. Specifically, the Path message sent by the first node carries the forward outgoing label of the first node and the path information of the node identifier, the inbound interface, and the outbound interface of all the downstream nodes on the LSP behind the first node. If the first node and the first There is one or more intermediate nodes between the two nodes, and the intermediate node receives the Path message sent by the upstream node on the LSP and obtains the forward outgoing label of the upstream node carried in the Path message, and the intermediate node Forward inbound interface index and forward outbound interface index, using the forward outgoing label of the intermediate node and the forward outgoing label of the upstream node obtained by the intermediate node, the forward inbound interface index of the intermediate node, and the forward outbound interface index Establishing a forward cross-connection of the LSP in the intermediate node, the intermediate node sending a Path message to the downstream node adjacent to the intermediate node on the LSP, where the forward outgoing label of the intermediate node is on the LSP and the intermediate node The downstream node of the neighbor is pre-assigned to an unused tag in the set of labels of the intermediate node. The intermediate node determines, according to the node identifier of the adjacent downstream node of the intermediate node included in the path information, to find a label set allocated by the downstream node to the intermediate node, and then uses an unused label in the label set as the middle The forward outgoing label of the node. The intermediate node forwards the forward label of the upstream node (the first node of the first intermediate node, the upstream node is the first node, and the upstream node is an intermediate node to other intermediate nodes) carried in the Path message. Set as the forward ingress label of the LSP at the local node, because the forward outgoing label of the upstream node is an unused label pre-allocated by the intermediate node, so the label is definitely available for use at the intermediate node, so Set it to the forward ingress label to establish a positive cross connect. The Path message sent by the intermediate node to the downstream carries the forward outgoing label of the intermediate node and the path information such as the node identifier, the outbound interface, and the inbound interface of all the downstream nodes of the intermediate node on the LSP. If there are multiple intermediate nodes between the first node and the second node, these intermediate nodes repeat the above steps. Optionally, if the LSP is configured with the bandwidth requirement, the intermediate node performs resource check and bandwidth allocation before establishing the cross-connection. If the bandwidth allocation fails, the LSP fails to be established, and the LSP fails to be sent to the adjacent upstream node. The message ends, and the Path message is no longer sent to the downstream node. The second node receives the Path message sent by the upstream node adjacent to the LSP, and obtains the second forward outgoing label of the upstream node and the second forward incoming interface index of the second node carried in the Path message, because the The second forward outgoing label is an unused label that the second node pre-allocates to its upstream node, so it is definitely idle, so the second forward outgoing label can be directly set as the forward incoming label of the node, and the second positive Establishing a forward cross-connection of the LSP at the second node to the ingress label and the second forward ingress interface index. Optionally, each node on the LSP behind the first node may also establish a forward cross connection and a reverse cross connection by using an established LSP in the prior art, so that the LSP is shortened compared with the prior art. The time that the adjacent node of the first node allocates label resources to the downstream node can also shorten the time for establishing the LSP to some extent.

Optionally, if the bidirectional LSP is established, the Path message sent by the first node to the downstream node that is adjacent to the first node on the LSP is further caused by the first node on the LSP. The downstream node other than the second node establishes a reverse crossover by using an unused label allocated from the label resource pool of the local node, path information carried in the Path message sent by the adjacent upstream node, and a reverse incoming label. The connection further causes the second node to establish a reverse cross-connection by using the path information carried in the Path message sent by the neighboring upstream node and the reverse incoming label, and switch the reverse traffic to the reverse cross-connection successfully. On the LSP. If there is one or more intermediate nodes between the first node and the second node, the intermediate node may also receive the Path message received by the intermediate node. Carrying the reverse ingress label of the upstream node, the reverse outbound interface index of the intermediate node, and the reverse inbound interface index, may utilize the reverse ingress label of the intermediate node and the reverse entry label of the upstream node obtained by the intermediate node, The reverse outbound interface index and the reverse inbound interface index of the intermediate node establish a reverse cross connection of the LSP in the intermediate node, and the intermediate node sends a Path message to the downstream node adjacent to the intermediate node on the LSP. The forward outgoing label of the intermediate node is an unused label in the label set pre-assigned to the intermediate node by the downstream node adjacent to the intermediate node on the LSP. The intermediate node sets the reverse ingress label of the upstream node that is carried in the Path message with the neighboring node to the reverse outgoing label of the LSP, thereby establishing a reverse cross connection. The Path message sent by the intermediate node to the downstream carries the forward outgoing label of the intermediate node, the reverse incoming label, and the path information of the node identifier, the outbound interface, and the inbound interface of all the downstream nodes of the intermediate node on the LSP. If there are multiple intermediate nodes between the first node and the second node, these intermediate nodes repeat the above steps. Optionally, if the LSP is configured with the bandwidth requirement, the intermediate node performs resource check and bandwidth allocation before establishing the cross-connection. If the bandwidth allocation fails, the LSP fails to be established, and the LSP fails to be sent to the adjacent upstream node. The message ends, and the Path message is no longer sent to the downstream node. The second node may also obtain a second reverse incoming label of the upstream node and a second reverse outgoing interface index of the second node carried in the Path message received by the second node, and use the second reverse outgoing label and the second reverse The outbound interface index establishes a reverse cross-connection of the LSP at the second node. Optionally, after the second node establishes the reverse cross-connection of the LSP on the node, the reverse traffic may be switched to the LSP.

Step S205, optionally, after the forward cross connection of the first node is established, before the forward cross connection of the second node is established, although the LSP is not finally completed, the first node may cut the forward traffic first. Go to the LSP. When the LSP has not been finalized, if the node receiving the traffic has not established the forward cross-connection of the node, it can cache data traffic or discard the data traffic. After the node receiving the traffic is established, the forward traffic is transmitted to the downstream node. If there is buffered data traffic, the corresponding data traffic is released and transmitted to the downstream node. In this way, the LSP can be used to transmit forward traffic for the first time after it is built. Optionally, you can enable LSP operation, administration, and maintenance (OAM) before switching forward traffic or reverse traffic. "Life check, it is good to determine the positive direction path at the first node and the last node, and then switch forward traffic or reverse traffic. The method of continuity check is to send a continuity check (CCM) message in the CCM message. Carrying information that can confirm that the second node has established a forward cross-connection, such as carrying a specific identifier, a specific CCM transmission interval, etc., so that the first node identifies the identifier and determines that the forward cross-connection of the second node has been If it is established, the forward traffic is switched. Because the time for enabling OAM and sending CCM messages is very short compared to the time of the Path process and the Resv process, the time for establishing the LSP is generally saved, and the service access is shortened. Time or business recovery time.

Optionally, the second node may send a Resv message to initiate a Resv process to check the cross-connection status of the LSP.

Optionally, other types of messages can be used to establish LSPs if they can be used to carry corresponding LSP path information and label information. In the method for establishing an LSP according to the embodiment of the present invention, the label resource between the nodes in the MPLS network is allocated in advance before the LSP is established, and the first node can establish a forward cross connection in the Path process, and the first node in the prior art. Compared with the method that the Path process and the Resv process are required to establish an LSP forward cross connection, the LSP establishment time is shortened. If all the nodes on the entire LSP are assigned labels before the LSP is set up, all nodes can establish a forward cross-connection in the Path process, which can greatly shorten the LSP establishment time. At the same time, the forward traffic can be switched after the forward cross-connection is established on the first node, and the reverse traffic is switched after the reverse-cross connection of the last node, which ensures that the new LSP can be used for bearer services after being established. The method disclosed in the embodiment of the present invention shortens the time for establishing an LSP, thereby reducing service access time or service recovery time and improving user experience.

Embodiment 3: Embodiments of the present invention provide a method for establishing a label switching path LSP, where

The LSP is an LSP from the first node to the second node, and the third node is an intermediate node between the first node and the second node on the LSP, along the LSP from the first node to the The second node is forward, and the LSP is reversed from the second node to the first node along the LSP, as shown in FIG.

Step S301, optionally, before the first node initiates establishment of the LSP, that is, the first node calculates, according to a network topology of the multi-protocol label switching network, a path from the first node to the Before the LSP of the second node obtains the LSP path information of the LSP, the third node obtains the determined by the downstream node adjacent to the third node from a downstream node adjacent to the third node The set of tags that the third node can use, and stores the obtained set of tags. If the third node has stored a set of available labels assigned to adjacent downstream nodes on the LSP, the free labels in the set of labels can be directly utilized. Optionally, the third node allocates, to the adjacent upstream node on the LSP, a set of labels that can be used by the upstream node, so that it establishes a forward cross-connection in the Path process, if the upstream node has received the After the assigned tag set has been reached and there are free tags in the tag set, the third section can be used again. The method of assigning a label set; ^ method may be pre-allocation of labels between the nodes in the first embodiment. It should be noted that the pre-allocation label between the nodes may be the time when the network is initialized, or may be other time, but must be before the request to establish the LSP, that is, before the establishment of the LSP. That is to say, the embodiment of the present invention has already allocated the labels between the nodes before initiating the establishment of the LSP, so it is not necessary to request the downstream nodes to allocate the forward outgoing labels when establishing the LSP, and can be established in the Path process. Forward cross connection. Optionally, the pre-allocation of the label may be pre-allocating an alternate label set for each node in each existing LSP for use in a fault; or may be a virtual LSP in the network system in advance. The corresponding label is allocated, and the label allocated for the virtual LSP can be directly used when the signaling for establishing the LSP arrives; or all the nodes in the system allocate labels to the neighbor nodes.

Step S302, the third node receives a Path message sent by an upstream node adjacent to the LSP path, and the adjacent upstream node is in the third node in a forward direction of the LSP. Adjacent nodes upstream. The Path message is a message that is sent after the first node establishes a forward cross-connection and is forwarded by a node between the first node and the third node after establishing a forward cross-connection, where one node The downstream node is in the forward direction of the LSP. The node behind the node. The manner in which the first node establishes a forward cross-connection is the same as the manner in which the first node in the second embodiment establishes a forward cross-connection, and the intermediate node between the first node and the third node establishes a positive cross-connection. The manner in which the intermediate nodes establish a forward cross-connection is the same in the second embodiment, and details are not described herein again. Optionally, if the establishment is a bidirectional LSP, each node may also establish a reverse cross connection, which is also the same as the method in the second embodiment.

Step S303, the third node acquires the path information carried in the Path message received by the third node and the forward outgoing label of the upstream node adjacent thereto, and the downstream node adjacent to the LSP in the forward direction An unused label in the label set assigned thereto is used as the second forward outgoing label, and the obtained forward outgoing label of the upstream node adjacent thereto is used as the second forward incoming label, according to the second forward direction The outgoing label, the second forward incoming label, and the obtained path information establish a positive cross-connection. Optionally, if a bidirectional LSP is established, the third node may also use the information carried in the obtained Path message to establish a reverse cross connection. The method for establishing the forward cross connection and the reverse cross connection of the third node is the same as the method for establishing the forward cross connection and the reverse cross connection respectively with the intermediate node in the second embodiment, and details are not described herein again.

Step S304, the third node sends a Path message to the downstream node that is adjacent to the neighboring node, where the Path message carries the LSP path information of the downstream nodes of the third node and the second forward outgoing label. The Path message is used to establish a forward cross-connection for each downstream node of the third node on the LSP. The Path message causes a node other than the second node downstream of the third node on the LSP to use an unused tag of its label set pre-assigned to its neighboring downstream node, adjacent thereto The path information carried in the Path message sent by the upstream node establishes a forward cross-connection with the forward outgoing label, so that the second node establishes a positive crossover by using the path information carried in the Path message sent by the neighboring upstream node and the forward outgoing label. connection. Optionally, if a bidirectional LSP is established, a reverse cross connection can also be established at each node. The method for establishing a forward cross connection and the reverse cross connection between the node other than the second node and the second node downstream of the third node is the same as the method of the intermediate node and the second node in the second embodiment, respectively. Let me repeat.

Optionally, after the forward cross-connection of the first node is established, although the LSP is not finally completed, the first node may cut the forward traffic to the LSP, and receive the traffic when the LSP has not been finally completed. The node can buffer data traffic or discard data traffic. This ensures that the LSP can be used to transmit forward traffic for the first time after it is built. Optionally, if the LSP is configured with the bandwidth requirement, the first node performs the resource check and the bandwidth allocation before the cross-connection is established. If the bandwidth allocation fails, the LSP fails to be established, the process ends, and the Path message is not sent to the downstream node. .

Optionally, other types of messages can be used to establish an LSP if they can be used to carry the corresponding LSP path information and label information.

Optionally, after the forward cross connection of the first node is established, before the forward cross connection of the second node is established, although the LSP is not finally completed, the first node can cut the forward traffic first. The LSP comes up. When the LSP has not been finally built, if the node receiving the traffic has not established the forward cross-connection of the node, it can cache data traffic or discard the data traffic. After the node receiving the traffic is established, the forward traffic is transmitted to the downstream node. If there is buffered data traffic, the corresponding data traffic is released and transmitted to the downstream node. In this way, the LSP can be used to transmit forward traffic for the first time after being built. Optionally, each node except the third node on the LSP can also establish a forward cross connection and a reverse cross connection by using an established LSP in the prior art, so that the LSP is shortened compared with the prior art. The time for the adjacent downstream node of the third node to allocate the label resource to it can also shorten the time for establishing the LSP to some extent.

Optionally, the LSP operation, management, and maintenance (OAM) can be enabled before the forward traffic or the reverse traffic is switched, and the continuity check is performed to determine the positive direction at the first node and the last node. The path is good, then switch forward traffic or reverse traffic. The method of continuity check is to send a continuity check (CCM) message, the CCM message carrying information that can confirm that the second node has established a forward cross-connection, such as carrying a specific identifier, so that the first After the node identifies the identifier and determines that the forward cross-connection of the second node has been established, the forward traffic is switched. Because the time for enabling OAM and sending CCM messages is very short compared to the time of the Path process and the Resv process, the time for establishing an LSP is generally saved, and the service access time or service recovery time is shortened.

In the method for establishing an LSP according to the embodiment of the present invention, the label resource between nodes in the MPLS network is allocated in advance before the LSP is established, and the intermediate node on the LSP can establish a forward cross connection in the Path process, and the prior art Compared with the method that the intermediate node needs the Path process and the Resv process to establish an LSP forward cross connection, the LSP establishment time is shortened. If all the nodes on the entire LSP are assigned labels before the LSP is set up, all nodes can establish a forward cross-connection in the Path process, which can greatly shorten the LSP establishment time. At the same time, the forward traffic can be switched after the forward cross-connection is established on the first node, and the reverse traffic is switched after the reverse-cross connection of the last node, which ensures that the new LSP can be used for bearer services for the first time. The method disclosed in the embodiment of the present invention shortens the time for establishing an LSP, thereby reducing service access time or service recovery time and improving user experience.

Embodiment 4: An embodiment of the present invention provides a packet transport network device, as shown in FIG.

The device includes: a processing module, configured to establish a forward cross connection by using the label switching path LSP path information obtained by the label switching path and the first label from the storage module, where the first label is on the LSP path and the a downstream packet transport network device adjacent to the packet transport network device is pre-assigned to an unused tag in the tag set of the packet transport network device, the downstream packet transport network device; a generating module, configured to generate a Path message, The Path message carries the LSP path information of each packet transport network device downstream of the packet transport network device on the LSP, and the first label, where the destination address of the Path message is the LSP path and the packet An address of a downstream packet transport network device adjacent to the transport network device; a sending module, configured to send a message generated by the generating module; A storage module for storing information from the processing module. Optionally, after the forward cross-connection of the packet transport network device is established, the packet transport network device forward traffic before the forward cross-connection of the last packet transport network device in the forward direction of the LSP On the LSP that is switched; or, after receiving the continuity check CCM message sent by the last packet transport network device, the packet transport network device switches the forward traffic to the LSP, where the CCM report The message carries information for confirming that the last packet transport network device has established a forward cross-connection. Optionally, the processing module is further configured to establish, by using the LSP path information obtained by the LSP path information and the second label from the storage module, as a reverse ingress label, where the second label is the grouping An unused label in the label resource pool of the transport network device itself; the Path message also carries the second label. Optionally, the processing module is further configured to allocate, according to the device identifier, a label set to each of the packet transport network devices adjacent to the packet transport network device, where the device identifier is a device identifier of the neighboring packet transport network devices; The generating module is further configured to send, according to the result of the processing module allocation, a message to the neighboring packet transport network devices by using the allocated label set, where the message carries the device identifier of the packet transport network device, the device identifier of the device pointed by the message, and The set of labels assigned to the device with the device ID.

Specifically, the processing module may be configured to establish a forward cross connection by using path information of the label switched path LSP obtained by the label switching path and an unused label, where the LSP path information may be obtained by using the packet transmission network. The network topology of the MPLS network where the device is located is calculated and obtained. The unused tag is an unused tag pre-assigned to the packet transport network device's tag set in the downstream packet transport network device adjacent to the packet transport network device. Optionally, if the packet transport network device is an ingress node on the LSP, the device identifier of the network device of the neighboring downstream device may be used to query the neighbor information stored in the storage module. a label set pre-assigned to the packet transport network device, establishing an forward cross-connection by using an unused label in the label set and an outbound interface included in the LSP path information, and sending a Path message to the adjacent downstream packet transport network device . Optionally, if the packet transport network device is the first node of the LSP, after the forward cross connection of the first node is established, before the forward cross connection of the last node is established, although the LSP has not been finally completed, the packet is transmitted. The network device can cut the forward traffic to the LSP first. When the LSP has not been finalized, the packet transport network device receiving the traffic may cache the data traffic or discard the data traffic if it finds that the forward cross-connection on the device has not been established yet. After the packet transmission network device receiving the traffic is established, the forward traffic is transmitted to the downstream device. If there is buffered data traffic, the corresponding data traffic is released and transmitted to the downstream device. Optionally, the LSP operation, management, and maintenance (OAM) may be enabled before the forward traffic or the reverse traffic is switched, and the continuity check is performed on the packet transmission network device at the first node. The packet transport network device of the last node determines that the established LSP is good, and then switches forward traffic or reverse traffic. The method of continuity check is to send a continuity check (CCM) message, which carries the last packet transport network device on the LSP path, that is, the last node of the LSP has established a forward cross connection. Information, such as carrying a specific identifier, such that the packet transport network device can recognize the identifier After determining that the forward cross-connection of the last packet transport network device has been established, the forward traffic is switched. Because the time for enabling OAM and sending CCM messages is very short compared to the time of the Path process and the Resv process, the time for establishing an LSP is generally saved, and the service access time or service recovery time is shortened. In this way, the LSP can be used to transmit forward traffic for the first time after being built. Optionally, the method for establishing a reverse cross-connection is also performed by using the packet-transport network device. For example, the method for establishing a reverse cross-connection by the first node in Embodiment 2 is not described herein.

Optionally, the processing module is further configured to determine, according to a device identifier of each neighbor packet transport network device from the storage module or from the parsing module, a label set that is applicable to each neighbor packet transport network device, where the packet is The neighbor packet transport network device of the transport network device is a packet transport network device adjacent to the packet transport network device. The device identifier of the packet transport network device may be the device identifier of the device, or may be an Internet Protocol address of the device, or may be an integer. In short, it may be used for identifying by the first packet transport network device, or may be other An identifier that can be used for identification by the first packet transport network device. Optionally, the device identifier of the neighbor packet transport network device may be stored by the storage module. If the first packet transport network device does not know the device identifier of each neighbor packet transport network device, the internal gateway protocol may also be adopted. IGP) The message interacts with the network topology information and parses the corresponding message through the parsing module to obtain the device identifier of the neighbor packet transport network device. Determining the set of labels that can be used by the neighboring packet transport network device means assigning a label set to each device identifier in a locally available label resource pool, the label set including at least one label. For example, the device identifier of the neighbor packet transport network device may be used as a key to establish a corresponding entry, and the key set is assigned to the key. After the label set is allocated, it is sent to the storage module for storage. Optionally, the tag or tag set that has been assigned may be marked as assigned, and the tag or tag set marked as being allocated is only used by the neighbor packet transport network device assigned to the tag or tag set, before being released. Other neighbor packet transport network devices are not available.

Specifically, the generating module, the path information carried by the generated Path message includes, but is not limited to, a device identifier, an outbound interface, and an inbound interface index of each packet transport network device on the LSP after the packet transport network device, and the packet transmission The forward label of the network device. Optionally, when a reverse cross-connection is established, the Path message also carries a reverse-entry label. Optionally, the generating module is further configured to generate, according to the device identifier of the neighbor packet transmission network device from the storage module or the processing module, and the label set of the neighbor packet transmission network device determined by the processing module. And a message carrying the device identifier of the packet transport network device, the device identifier of the neighbor packet transport network device, and a label set allocated by the processing module to the neighbor packet transport network device. The message may be an extended IGP protocol message, an extended Ethernet packet, or other message type, as long as it can be used to carry the device identifier of the destination neighbor packet transport network device, and the first packet transport network device. The device identifier and the label set assigned by the first node to the destination neighbor node are sufficient. The destination address of the message may be a unicast address, and the content sent may be a device identifier of the destination neighbor packet transport network device, a device identifier of the first packet transport network device, and a first packet transport network device allocated to the destination neighbor packet transport network device. The label set, the sent content may also be an entry, where the entry includes the packet transport network device identifier of the first packet transport network device, and the first packet transport network device The packet transport network device identifier of the neighbor packet transport network device and the label set allocated by the first packet transport network device to the neighbor packet transport network devices, and the neighbor packet transport network device receiving the message may identify the network device through its own packet transport network device. Find the set of labels assigned to yourself in the table entry. The message may also be a broadcast address, and the sent content may be the above-mentioned packet transport network device identifier including the first packet transport network device, the packet transport network device identifier of all neighbor packet transport network devices of the first packet transport network device, and An entry of a label set assigned by the first packet transport network device to the neighbor packet transport network devices.

Optionally, the packet transport network device may include a parsing module, configured to parse the message received by the receiving module from the neighbor packet transport network device, and obtain the neighbor packet transport network device carried in the message The device identification and the set of tags assigned by the neighbor packet transport network device to the packet transport network device.

The storage module is configured to store information from the parsing module and the processing module. The stored content may include, but is not limited to, a device identifier of a neighbor packet transport network device, a label set assigned to its neighbor packet device by the packet transport network device, a correspondence between the two, and usage of the label set label. Information from the processing module includes, but is not limited to, information that modifies the usage status of the tag, tag set information, tag information, device identification information, and the like.

The Packet Transpor Network (PTN) device in the embodiment refers to a device that transmits data by using a packet switching technology, including but not limited to a label swi tching router (LSR) and a label swi tching edge. Router , LER ), switches, packet switching equipment, packet transport network equipment, etc.

The packet transport network device disclosed in the embodiment of the present invention allocates the label resource between the packet transport network devices in the MPLS network in advance before establishing the LSP, so that the allocated label can be directly utilized when the new LSP is established without re-allocation. The forward cross-connection can be established in the Path process. Compared with the previous method in which the Path process and the Resv process are required to establish an LSP forward cross-connection, the time for establishing the LSP is reduced. At the same time, the packet transmission network device at the LSP head node establishes a forward cross-connection, that is, the forward traffic is switched, and the new LSP can be used to carry the service for the first time, which shortens the service access time or service recovery time. , improved user experience.

Embodiment 5: Embodiments of the present invention provide a packet transport network device, as shown in FIG. 5.

The device includes: a receiving module, configured to receive a message; a parsing module, configured to parse the message received by the receiving module; and a processing module, configured to: forward the packet transport network from the parsing module to the label, and the The first label of the storage module serves as a forward outgoing label of the packet transport network device, according to a forward incoming label of the packet transport network device, a forward outgoing label of the packet transport network device, and a obtained label The path information of the switching path LSP establishes a forward cross-connection, wherein the packet transport network device is a packet transport network device on the LSP, and the first label is on the LSP path and the packet transport network device An adjacent downstream packet transport network device is pre-assigned to an unused tag in the set of labels of the packet transport network device, the downstream packet transport The processing module is further configured to determine, according to the device identifier from the storage module or the device identifier from the parsing module, a label set that can be used by the packet transport network device that has the device identifier, where the device identifier is the LSP. a device identifier of the upstream packet transport network device adjacent to the packet transport network device in the forward direction; a generating module, configured to generate a Path message, where the Path message carries the packet transport network device downstream on the LSP The LSP path information of each packet transport network device and the address of the downstream packet transport network device adjacent to the network device; the generating module is further configured to generate an advertisement message according to the device identifier and the label set determined by the processing module The notification message carries the device identifier, the device identifier of the packet transport network device itself, and the upstream packet transport network device that the processing module sends the network device adjacent to; the sending module is configured to send the generating module a generated message, configured to store information from the parsing module and the processing module Optionally, the processing module is further configured to: forward the packet transport network from the parsing module to an outgoing label, and use an unused label determined by the packet transport network device from its own label resource pool. a reverse ingress label of the packet transport network device, establishing a reverse cross connection by using a reverse outgoing label of the packet transport network device, a reverse incoming label of the packet transport network device, and the LSP path information; The Path message also carries a reverse incoming label of the packet transport network device.

Specifically, the method for the processing module to obtain the path information of the forward outgoing label and the label switched path LSP of the upstream packet transport network device adjacent to the packet transport network device may be, by receiving and parsing, sending, by the upstream packet transport network device The Path message is obtained. Optionally, if the packet transport network device is an intermediate node on the LSP, the neighboring packet transport network device may be queried according to the related information stored in the storage module of the device identifier of each of the adjacent downstream transport network devices. The set of labels pre-assigned to it, using an unused label in the set of labels and the incoming and outgoing interface indexes carried in the Path message sent by the neighboring upstream packet transport network device and the forward outgoing label establishment Forward cross-connect and send Path messages to neighboring downstream packet transport network devices. An unused label in the label set may be searched in the stored label set according to the device identifier of the next LSP transport network device carried in the Path message. Optionally, the method for establishing a reverse cross-connection is also performed by using the packet transport network device. For example, the method for establishing a reverse cross-connection between the intermediate nodes in the second embodiment is not described herein.

The method for the processing module to determine the available label set of the upstream packet transport network device adjacent to the packet transport network device, such as the method for implementing the label allocation in the first embodiment, is not described again. a processing module, configured to determine, according to a device identifier of each neighbor packet transport network device from the storage module or from the parsing module, a label set usable by each of the neighbor packet transport network devices, where the neighbor of the packet transport network device The packet transport network device is a packet transport network device adjacent to the packet transport network device. The device identifier of the packet transport network device may be the device identifier of the device, or may be the network of the device The protocol address may also be an integer. In short, it may be used for identification by the first packet transport network device, or may be other identifiers that can be used for identification by the first packet transport network device. Optionally, the device identifier of the neighbor packet transport network device may be stored by the storage module. If the first packet transport network device does not know the device identifier of each neighbor packet transport network device, the internal gateway protocol may also be used. IGP) The message interacts with the network topology information and parses the corresponding message through the parsing module to obtain the device identifier of the neighbor packet transport network device. Determining the set of labels that can be used by the neighboring packet transport network device means assigning a label set to each device identifier in a locally available label resource pool, the label set including at least one label. For example, the device identifier of the neighboring packet transport network device may be used as a key to establish a corresponding entry, and the key set is assigned to the key. After the label set is allocated, it is sent to the storage module for storage. Optionally, the tag or tag set that has been assigned may be marked as assigned, and the tag or tag set marked as being allocated is only used by the neighbor packet transport network device assigned to the tag or tag set, before being released. Other neighbor packet transport network devices are not available.

Specifically, the generating module, the path information carried by the generated Path message includes, but is not limited to, a device identifier, an outbound interface, and an inbound interface index of each packet transport network device on the LSP after the packet transport network device, and the packet transmission The forward label of the network device. Optionally, when a reverse cross-connection is established, the Path message also carries a reverse-entry label. Optionally, the generating module is further configured to generate, according to the device identifier of the neighbor packet transmission network device from the storage module or the processing module, and the label set of the neighbor packet transmission network device determined by the processing module. And a message carrying the device identifier of the packet transport network device, the device identifier of the neighbor packet transport network device, and a label set allocated by the processing module to the neighbor packet transport network device. The message may be an extended IGP protocol message, an extended Ethernet packet, or other message type, as long as it can be used to carry the device identifier of the destination neighbor packet transport network device, and the first packet transport network device. The device identifier and the label set assigned by the first node to the destination neighbor node are sufficient. The destination address of the message may be a unicast address, and the content sent may be a device identifier of the destination neighbor packet transport network device, a device identifier of the first packet transport network device, and a first packet transport network device allocated to the destination neighbor packet transport network device. The set of labels may also be an entry, where the entry includes the packet transport network device identifier of the first packet transport network device, and the packet transport network of all neighbor packet transport network devices of the first packet transport network device. The device identifier and the set of labels allocated by the first packet transport network device to the neighbor packet transport network devices, and the neighbor packet transport network device receiving the message may look up the label set assigned to itself in the entry by its own packet transport network device identifier. . The message may also be a broadcast address, and the sent content may be the above-mentioned packet transport network device identifier including the first packet transport network device, the packet transport network device identifier of all neighbor packet transport network devices of the first packet transport network device, and An entry of a label set assigned by the first packet transport network device to the neighbor packet transport network devices.

The parsing module is configured to parse a message received by the receiving module from the neighbor packet transport network device, and obtain a device identifier of the neighbor packet transport network device carried in the message, and the neighbor packet transport network A set of labels assigned by the device to the packet transport network device. At the same time, the parsing module is further configured to parse the sending of the adjacent upstream device of the packet transport network device received by the receiving module Path message, and get the information carried in it. Optionally, the packet transport network device may include a storage module, configured to store information from the parsing module and the processing module. The stored content may include, but is not limited to, a device identifier of a neighbor packet transport network device, a label set allocated by the packet transport network device to its neighbor packet device, a correspondence between the two, and a usage of the label in the label set.

The Packet Transpor Network (PTN) device in the embodiment refers to a device for transmitting data by using a packet switching technology, including but not limited to a label switching router (LSR) and a label switching edge router (labe l swi). Tching edge router, LER ), switches, packet switching equipment, packet transport network equipment, etc.

The packet transport network device disclosed in the embodiment of the present invention allocates the label resource between the packet transport network devices in the MPLS network in advance before establishing the LSP, so that the allocated label can be directly utilized when the new LSP is established without re-allocation. The forward cross-connection can be established in the path process. Compared with the previous method in which the path process and the Resv process are required to establish an LSP forward cross-connection, the time for establishing the LSP is reduced, and the service access time or service is shortened. Recovery time has improved the user's body.

Embodiment 6: Embodiments of the present invention further provide a network device, as shown in FIG. 9, including a processor, a memory, a receiver, and a transmitter, wherein the receiver is coupled to the processor and the memory, the transmitter and the processor, and Memory coupling. The network device can be used to perform the methods as in the first, second and third embodiments. Specifically, the receiver is configured to receive a message from outside the network device; the memory is configured to store corresponding information; the transmitter is configured to send a message to the outside of the network device; the processor parses and processes the received message, and can be used to generate Corresponding messages are sent by the sender. Specifically, the processor has the functions of the processing module, the generating module, and the parsing module in Embodiments 4 and 5. The processor may be a general-purpose processor, such as an integrated circuit IC, and the program executed by the processor may be stored in a memory; the processor may also be an application specific integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable gate array) ), or other class 4 to functional devices.

The packet transport network device disclosed in the embodiment of the present invention allocates the label resource between the packet transport network devices in the MPLS network in advance before establishing the LSP, so that the allocated label can be directly utilized when the new LSP is established without re-allocation. The forward cross-connection can be established in the path process. Compared with the previous method in which the path process and the Resv process are required to establish an LSP forward cross-connection, the time for establishing the LSP is reduced, and the service access time or service is shortened. Recovery time improves the user experience.

Embodiment 7 The embodiment of the present invention further provides a network system, where the network system includes: the network system includes at least a first packet transport network device, a second packet transport network device, and a third packet transport network device, where a packet transport network device is connected to the second packet transport network device by the third packet transport network device; from the first packet transport network device to the second packet transport network device In the forward direction, the direction from the second packet transport network device to the first packet transport network device is reversed; the first packet transport network device is configured to calculate a network according to the network topology of the network system Obtaining path information of the LSP from the LSP of the first packet transport network device to the second packet transport network device, establishing a forward cross connection by using the first forward outgoing label and the path information, and performing positive forward cross connection to the LSP Transmitting, by the downstream packet transport network device adjacent to the first packet transport network device, a first Path message, where the first forward outgoing label is in the forward direction of the LSP and the first packet transport network a downstream packet transport network device adjacent to the device is pre-assigned to an unused tag in the tag set of the first packet transport network device; the third packet transport network device is configured to receive the LSP in the forward direction thereof a second Path message sent by the adjacent upstream packet transport network device, and the forward outgoing label carried in the second Path message is obtained as a forward label of the third packet transport network device, The path information carried in the second Path message acquired by the third packet transport network device, the forward inbound label of the third packet transport network device, and the forward outgoing label of the third packet transport network device Establishing a forward cross-connection, and sending a third Path message to the downstream packet transport network device adjacent to the third packet transport network device in the forward direction of the LSP, where the third packet transport network device forwards a tag is an unused tag of a tag set pre-assigned to the third packet transport network device by a downstream packet transport network device adjacent to the third packet transport network device in a forward direction of the LSP; a second packet transport network device, configured to receive a fourth Path message sent by the upstream packet transport network device adjacent to the LSP in the forward direction, and obtain the forward outgoing label carried in the obtained fourth Path message As a forward inbound label of the second packet transport network device, and using the forward inbound label of the second packet transport network device and the obtained path information carried in the fourth Path message It is connected to the cross. Optionally, the first packet transport network device is further configured to: after the forward cross-connection connection of the first packet transport network device is established, before the forward cross-connection of the second packet transport network device is established, Switching to the LSP on the LSP; or, after receiving the continuity check CCM message sent by the second packet transport network device, switching the forward traffic to the LSP, the CCM packet There is information that can confirm that the second packet transport network device has established a forward cross-connection. Optionally, the first packet transport network device is further configured to determine that an unused label in the label resource pool of the first packet transport network device itself is a reverse incoming label of the first packet transport network device. Establishing a reverse cross-connection by using the reverse-entry label of the first packet transport network device and the obtained LSP path information, and carrying the reverse-entry label of the first packet transport network device in the first Path message The third packet transport network device is further configured to use, as the third packet, a reverse incoming label of an upstream packet transport network device adjacent to the third packet transport network device that is carried in the received second Path message. a reverse outgoing label of the transport network device, determining that an unused label in the label resource pool of the third packet transport network device itself is a reverse incoming label of the third packet transport network device, using the third packet The reverse incoming label of the transport network device and the obtained LSP path information establish a reverse cross-connection, and carry the reverse incoming label of the third packet transport network device in the third Path message. The second packet transport network device is further configured to use, as the second packet, a reverse incoming label of an upstream packet transport network device adjacent to the second packet transport network device that is carried in the received fourth Path message. a reverse outgoing label of the transport network device, determining an unused standard in the label resource pool of the second packet transport network device itself The reverse incoming label of the second packet transport network device is signed, and the reverse cross-connect is established by using the reverse incoming label of the second packet transport network device and the obtained LSP path information.

Specifically, the first packet transport network device is connected to the second packet transport network device by using the third packet transport network device, and may be directly connected, or may be indirectly connected through other packet transport network devices. For example, between the first packet transport network device and the third packet transport network device, there may be a packet transport network device between the second packet transport network device and the third packet transport network device. Optionally, the network device may be the packet transport network device in Embodiment 5. Optionally, the method for allocating the label pre-allocation by each packet transport network device in the network system may be: pre-assigning an alternate label set to each node in each existing LSP for use in the event of a fault; or The virtual LSP is allocated a corresponding label in the network system. When the signaling of establishing the LSP arrives, the label allocated for the virtual LSP may be directly used; or all nodes in the system may assign labels to the neighbor nodes. The method of specific allocation is as described in the first embodiment. |Optional, the first packet transport network device is the same, and will not be described again. Optionally, the method for establishing the forward and reverse crossover of the third packet transport network device may be the same as the method for establishing the third node in the third embodiment, and details are not described herein. Optionally, the method for establishing the second node is the same and will not be described again. Optionally, on the LSP, another packet transport network device other than the third packet transport network device between the first packet transport network device and the first packet transport network device establishes a forward crossover and a reverse crossover. The method is the same as the method of the third packet transport network device.

Each packet transport network device in the network system allocates a set of labels usable by each of the neighbor packet transport network devices for each neighbor packet transport network device, and transmits a message announcement to each of the neighbor packet transport network devices a set of labels that can be used to implement label pre-allocation between each packet transport network device in the system, wherein a neighbor packet transport network device of a packet transport network device refers to a packet transport network device adjacent to the packet transport network device The label set includes at least one label, and a message sent to any one of the neighbor packet transport network devices carries a device identifier of the neighbor packet transport network device, and sends a packet transmission of the message The device identifier of the network device and the set of labels assigned by the packet transport network device that sent the message to the neighbor packet transport network device. The method for allocating a label set by each packet transport network device in the system is the allocation method introduced in the first embodiment of the present invention, and details are not described herein again.

Optionally, the first packet transport network device switches the forward traffic to the LSP before the forward cross-connection of the second packet transport network device is established; or the first packet transport network device After receiving the continuity check CCM message sent by the second packet transport network device, the forward traffic is switched to the LSP, and the CCM packet carries the device that can confirm that the second packet transport network device is established. Positive cross-connect information. When the bidirectional LSP is established, when the second packet transport network device establishes a reverse cross connection, the reverse traffic can be switched to the established LSP. The method for the specific forward traffic and the reverse traffic switching may be the method described in the second embodiment or the third embodiment, and details are not described herein again. The network system disclosed in the embodiment of the present invention allocates label resources between the packet transport network devices in the MPLS network in advance before establishing the LSP, so that the newly allocated LSP can directly utilize the allocated label without re-allocation. The Path process can establish a forward cross-connection. Compared with the prior art method that requires a Path process and a Resv process to establish an LSP forward cross-connection, the time for establishing an LSP is reduced. At the same time, the forward packet traffic is switched after the packet transport network device at the LSP head node establishes the forward cross-connection, and the reverse traffic is switched after the packet transport network device at the end node of the LSP establishes the reverse cross-connection. After the new LSP is established, it can be used to carry services for the first time, which shortens the service access time or service recovery time and improves the user experience. Through the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented in hardware, firmware implementation, or a combination thereof. When implemented in software, the functions described above may be stored in or transmitted as one or more instructions or code on a computer readable medium. Computer readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one location to another. A storage medium may be any available media that can be accessed by a computer. By way of example and not limitation, computer readable media may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage media or other magnetic storage device, or can be used for carrying or storing in the form of an instruction or data structure. The desired program code and any other medium that can be accessed by the computer. Also. Any connection may suitably be a computer readable medium. For example, if the software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable , fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, wireless, and microwaves are included in the fixing of the associated media. As used in the present invention, a disk and a disc include a compact disc (CD), a laser disc, a compact disc, a digital versatile disc (DVD), a floppy disc, and a Blu-ray disc, wherein the disc is usually magnetically copied, and the disc is The laser is used to optically replicate the data. Combinations of the above should also be included within the scope of the computer readable media.

In summary, the above description is only a preferred embodiment of the technical solution of the present invention, and is not intended to limit the scope of the present invention. Any modifications, equivalents, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Claim

A method for establishing a label switched path LSP, which is characterized by:

The first node calculates an LSP from the first node to the second node according to the network topology of the multi-protocol label switching network, and obtains LSP path information of the LSP;

The first node establishes a forward cross-connection by using a first forward outgoing label and a first forward outgoing interface index of the first node in the LSP path information, where the first forward outgoing label is a downstream node adjacent to the first node on the LSP is pre-assigned to an unused label in a label set of the first node; a downstream node adjacent to the first node is in the LSP a neighboring node downstream of the first node in a forward direction; a forward direction from the first node to the second node along the LSP, and a second along the LSP from the second node to the first node The first node sends a first Path message to the downstream node that is adjacent to the first node, where the first Path message carries the in the forward direction of the LSP. The LSP path information of each node downstream of the first node and the first forward outgoing label, where the first Path message is used to establish a positive node in each of the nodes downstream of the first node in the forward direction of the LSP. Connect to the cross.

2. The method according to claim 1, wherein the method comprises:

The first node switches the forward traffic to the LSP after the forward cross-connection of the first node is established and before the forward cross-connection of the second node is established;

Or, after receiving the continuity check CCM message from the second node, the first node switches the forward traffic to the LSP, where the CCM message carries a confirmation that the second node has been used. Establish information about positive cross-connections.

The method according to claim 1 or 2, wherein the method further comprises: the first node utilizing a reverse ingress label of the first node and the first one of the LSP path information The reverse inbound interface of the node establishes a reverse cross-connection, and the reverse ingress label of the first node is an unused label determined by the first node from the label resource pool of the local node; The message further carries a reverse ingress label of the first node, where the first Path message is further configured to establish a reverse cross connection at each node downstream of the first node in a forward direction of the LSP.

The method according to any one of claims 1 to 3, further comprising:

Calculating, by the first node, an LSP from the first node to the second node according to a network topology of the multi-protocol label switching network, before obtaining the LSP path information of the LSP, the first node Obtaining the label set at a downstream node adjacent to the first node, where the label set is a label set that is available to the first node determined by a downstream node adjacent to the first node; The set of tags obtained.

5. A method for establishing a label switched path LSP, where the LSP is from a first node to a second node The LSP of the point, the third node is an intermediate node between the first node and the second node on the LSP, and the LSP is forward from the first node to the second node along the LSP, along the The LSP is reversed from the second node to the first node, and is characterized by:

The third node receives a second Path message sent by an upstream node adjacent to the LSP path, and the upstream node adjacent thereto is in the forward direction of the LSP. Adjacent node

Obtaining, by the third node, the path information carried in the second Path message that is received by the third node, and the first forward outgoing label of the upstream node that is adjacent to the LSP, and the downstream of the LSP in the forward direction An unused label in the label set assigned to the node as the second forward outgoing label, and the first forward outgoing label as the second forward incoming label, according to the second forward outgoing label, Forming a positive cross-connection by the second forward-in label and the obtained path information;

The third node sends a third Path message to the downstream node that is adjacent to the third path message, where the third Path message carries an LSP path of each node that is downstream of the third node in the forward direction of the LSP. The information and the second forward outgoing label, the third Path message is used to establish a forward cross connection at each node downstream of the third node in the forward direction of the LSP.

The method according to claim 5, wherein the method further comprises:

Obtaining, by the third node, a first reverse incoming label of the upstream node that is adjacent to the second Path message that is received by the third node, and using the first reverse incoming label as the third node a second reverse outgoing label, the unused label determined by the third node from the label resource pool of the local node is used as the second reverse incoming label of the third node, according to the second reverse Establishing a reverse cross-connection by the label, the second reverse-entry label, and the reverse-input interface index and the reverse-out-interface index of the third node in the LSP path information;

The third Path message further carries the second reverse ingress label, where the third Path message is further used to establish a reverse direction with each downstream node adjacent to the third node in the forward direction of the LSP. Cross connection.

The method according to claim 6, wherein the method further comprises:

Before the first node initiates the establishment of the LSP, the third node determines, in the label resource pool that can be used by the node, the label that can be used by the upstream node adjacent to the neighboring node And transmitting a message to the upstream node adjacent thereto to announce the determined set of tags.

A packet transport network device, wherein the packet transport network device comprises: a processing module, configured to establish a forward cross connection by using the label switched path LSP path information obtained by the label switching path and the first label from the storage module. The first label is an unused label of a label set pre-assigned to the packet transport network device by a downstream packet transport network device adjacent to the packet transport network device on the LSP path, The downstream packet transport network device is a packet transport network device downstream of the packet transport network device in a forward direction of the LSP path; a generating module, configured to generate a Path message, where the Path message carries the LSP path information of each of the downstream packet transport network devices and the first label, where the destination address of the Path message is the LSP path and the An address of a downstream packet transport network device adjacent to the packet transport network device;

a sending module, configured to send a message generated by the generating module;

The storage module is configured to store information from the processing module.

The packet transmission network device according to claim 8, further comprising: the processing module is further configured to: after the forward cross connection of the packet transport network device is established, in a forward direction of the LSP Before the forward cross-connection of the last packet transport network device is established, the forward traffic is switched to the LSP;

Or the processing module is further configured to: after receiving the continuity check CCM message sent by the last packet transport network device, switch the forward traffic to the LSP, where the CCM packet carries The last packet transport network device has established information for a forward cross-connect.

10. The packet transport network device according to claim 9, wherein:

The processing module is further configured to establish, by using the LSP path information obtained by the LSP path information and the second label from the storage module, as a reverse incoming label, where the second label is the packet transport network device itself. An unused tag in the tag resource pool;

The generating module is further configured to carry the second label in the Path message.

A packet transport network device, wherein the packet transport network device comprises: a receiving module, configured to receive a message;

a parsing module, configured to parse the message received by the receiving module;

a processing module, configured to forward a forward outgoing label of an upstream packet transport network device adjacent to the packet transport network device from the parsing module as a forward incoming label of the packet transport network device, from the storage module a first label as a forward outgoing label of the packet transport network device, a forward incoming label according to the packet transport network device, a forward outgoing label of the packet transport network device, and a label switch from the parsing module The path information of the path LSP establishes a forward cross-connection, wherein the packet transport network device is a packet transport network device on the LSP, and the first label is on the LSP path and the packet transport network device a downstream downstream packet transport network device pre-assigned to an unused tag in the set of labels of the packet transport network device, the downstream packet transport network device; further for identifying a device identifier from the storage module or from the parsing module Determining a set of labels usable by the packet transport network device having the device identifier, where the device identifier is the L a device identifier of an upstream packet transport network device adjacent to the packet transport network device in the forward direction of the SP;

a generating module, configured to generate a Path message, where the Path message carries the part on the LSP The LSP path information of each packet transport network device downstream of the group transport network device and the first label, the address of the downstream packet transport network device; and the method further configured to generate an advertisement according to the device identifier and the label set determined by the processing module a message, the advertisement message carrying the device identifier, the device identifier of the packet transport network device, and a label set determined by the processing module, where the destination address of the advertisement message is in the forward direction of the LSP An upstream packet transport network device adjacent to the packet transport network device;

The storage module is configured to store information from the parsing module and the processing module.

12. The packet transport network device according to claim 11, wherein:

The processing module is further configured to use a reverse inbound label of an upstream packet transport network device adjacent to the packet transport network device from the parsing module as a reverse outgoing label of the packet transport network device, An unused label determined by the packet transport network device from its own label resource pool as a reverse incoming label of the packet transport network device, utilizing a reverse outgoing label of the packet transport network device, the packet transport network device Reverse inbound label and the LSP path information establish a reverse cross connection;

The generating module is further configured to carry a reverse ingress label of the packet transport network device in the Path message.

13. A network system, characterized by:

The network system includes at least a first packet transport network device, a second packet transport network device, and a third packet transport network device, and the first packet transport network device and the second packet transport network device pass the third packet transport network device The devices are connected; the direction from the first packet transport network device to the second packet transport network device is forward, and the direction from the second packet transport network device to the first packet transport network device is reversed;

The first packet transport network device, configured to calculate an LSP from the first packet transport network device to the second packet transport network device according to a network topology of the network system, to obtain path information of the LSP, Transmitting a forward cross-connection by using the first forward outgoing label and the path information, and sending a first Path message to a downstream packet transport network device adjacent to the first packet transport network device in a forward direction of the LSP. The first forward outgoing label is an unused one of the label sets pre-assigned to the first packet transport network device by the downstream packet transport network device adjacent to the first packet transport network device in the forward direction of the LSP. s Mark;

The third packet transport network device is configured to receive a second Path message sent by the upstream packet transport network device adjacent to the LSP in the forward direction, and the forward direction carried in the acquired second Path message Using the label as the forward inbound label of the third packet transport network device, using the path information carried in the second Path message obtained by the third packet transport network device, and the third packet transport network device Forward forwarding label and forward outgoing label of the third packet transport network device establish forward communication a fork connection, and sending a third Path message to the downstream packet transport network device adjacent to the third packet transport network device in the forward direction of the LSP, where the forward outgoing label of the third packet transport network device is Determining, by the downstream packet transport network device adjacent to the third packet transport network device in the forward direction of the LSP, an unused label in a label set of the third packet transport network device;

The second packet transport network device is configured to receive a fourth Path message sent by the upstream packet transport network device adjacent to the LSP in the forward direction of the LSP, and the positive result carried in the acquired fourth Path message The outgoing label is used as the forward inbound label of the second packet transport network device, and is established by using the forward inbound label of the second packet transport network device and the path information carried in the acquired fourth Path message. Forward cross connection.

14. The network system of claim 13 wherein:

The first packet transport network device is further configured to switch the forward traffic to after the forward cross-connection establishment of the first packet transport network device and before the forward cross-connection of the second packet transport network device is established On the LSP;

Or, after receiving the continuity check CCM message sent by the second packet transport network device, switching the forward traffic to the LSP, where the CCM packet carries the second The packet transport network device has established information for a positive cross-connect.

15. A network system according to claim 13 or 14, characterized in that:

The first packet transport network device is further configured to determine that an unused label in the label resource pool of the first packet transport network device itself is a reverse incoming label of the first packet transport network device, by using the first a reverse ingress label of the packet transport network device and the obtained LSP path information establishes a reverse cross connection, and carries the reverse ingress label of the first packet transport network device in the first Path message;

The third packet transport network device is further configured to determine, in the received label packet network device, a reverse outgoing label of the packet transport network device, where the third packet transport network device itself is in a label resource pool. An unused tag is a reverse ingress label of the third packet transport network device, and a reverse cross-link is established by using the reverse incoming label of the third packet transport network device and the obtained LSP path information, and the The reverse ingress label of the three packet transport network device is carried in the third Path message;

The second packet transport network device is further configured to determine, in the received packet header network device, a reverse outgoing label of the packet transport network device, where the second packet transport network device itself is in a label resource pool. An unused tag is a reverse incoming tag of the second packet transport network device, and a reverse cross-connect is established using the reverse incoming tag of the second packet transport network device and the obtained LSP path information.