WO2009009992A1 - A method, system, source end and destination end for indexing the label switching path by means of a label - Google Patents

Abstract

A method, system, source end and destination end for indexing the Label Switching Path (LSP) by means of a label are disclosed. In the present invention, a message is received that carries the Operation Administration and Maintenance (OAM) label and an inner-layer label for identifying the forward LSP, and the forward LSP with failure is indexed in accordance with the inner-layer label. Therefore, according to the present invention, in case of the backward channel being shared, Multiple Point to Point (Mp2p) LSP or Penultimate Hop Popping (PHP), the end which has received the message can index the forward LSP with failure in accordance with the label carried in the message. Thus, it is possible to support the OAM functionality in the case of the backward channel being shared, Mp2p LSP or PHP, so as to extend the application field of label indexing.

Description

 Method, system, source and sink for exchanging paths using label index labels

 The present invention relates to the field of communications, and more particularly to techniques for using a label index label switched path. Background technique

 OAM (Operation, Administration & Maintenance) functions simplify network operations, monitor network performance, and reduce network operating costs. It is especially important in networks that provide QoS (Quality of Service) assurance. MPLS (Multiple Protocol Label Switching) technology is a key technology for scalable next-generation networks. It supports QOS and multiple network services. It also requires OAM functions, called MPLS OAM functions.

 When the MPLS OAM function is implemented, the source periodically sends MPLS OAM packets, such as CV.

(Connected Verification, Connected '1' Health Verification), FFD (Fast Failure Detection) message; The sink performs connectivity detection based on the MPLS OAM packet, such as whether the CV or FFD packet can be detected. Regularly received, the content of the message is correct, etc., and the type of defect generated is determined according to the detection result; when the sink detects the defect, the BDI is sent through the reverse channel.

(Backward Defect Indicator) message is sent to the source end; the source end indexes the Label LSP (Label Switched Path) that is defective according to the label (label) carried in the BDI packet, and captures Corresponding switching measures. The format of the MPLS OAM packet is as shown in Figure 1:

 It can be seen that the outer label of the MPLS OAM is MPLS label, which can be used as the outgoing label of the LSP. The inner label value of the packet is 14 ( OAM Route alert label ), and the rest is OAM Payload ( OAM payload).

 In the process of implementing the present invention, the inventors have found that at least the following technical problems exist in the prior art:

When an LSP that is defective by the label index is used, it can be applied in the case of exclusive back channel. In this case, you need to configure a reverse LSP for the LSP that is enabled with the OAM function. If the LSP is faulty, the BDI message is sent to the configured LSP. After the source end receives the BDI, the source device can uniquely index the LSP that is defective by using the label value of the outer label in the packet, thereby performing operations such as switching the LSP. However, the method of using the label to index defective LSPs does not support OAM in the following three cases:

 The first case: sharing the reverse channel

 When the sink sends the BDI packet to the source through the shared reverse LSP, the outer label of the BDI packet is the same. Therefore, the source cannot index the LSP path that is faulty according to the outer label.

 The second case: Mp2p (Multiple Point to Point, label merging) LSP

Mp2p, also known as the label merge technology, the idea of the technology is: When the packet data with different tags arrives at an LSR (Label Switched Router) node (called a sink node), the LSR node Different inbound tags are merged and mapped to the same outgoing tag; the packet data is output using the same outgoing tag.

 In this case, if a plurality of LSP paths are aggregated on an LSR node and an OAM detection packet is sent, at the next hop node of the LSR node, multiple LSP paths are received within a specified time. The packets transmitted on the board, but the inbound labels of the packets are the same for the node. Therefore, the node considers that all the packets it receives are transmitted from the same LSP path, which is easy to generate dExcess. A defect, that is, the number of messages transmitted from the same LSP path within a specified time exceeds a set limit. At this time, it is actually possible that all the LSP paths are normal, and thus there may be a case of falsely reporting a defective LSP.

 In addition, even if an LSP path fails, the sink end may not be able to detect it because it can receive the detection packet sent through other LSP paths, so the OAM function cannot be performed well.

Even if the sink detects a defect, because of the packet data sent by multiple LSP paths at the sink end The corresponding inbound labels are the same, so the sink cannot know which LSP path has failed, and thus cannot inform the source.

 The third case: PHP (Penultimate Hop Popping, the penultimate hop pop) The trick is that the outermost mark in the tag stack is popped up in the penultimate LSR in the LSP path, not in the LSP path. The exit LSR is ejected. The penultimate LSR decides which egress LSR in the LSP path forwards the packet data according to the tag located at the top of the stack, and ejects the outermost tag in the tag stack, and sends the tags of other layers together with the packet data. The egress LSR, that is, the sink end of the LSP path, when receiving the packet data, determines the forwarding of the packet data according to the tag located at the top of the stack. If the packet data contains only one tag, after the penultimate hop is popped up, the egress LSR in the LSP path makes a forwarding decision based on the network layer packet header of the packet data.

 In this case, the outermost label is not available on the sink end of the LSP path. Therefore, it is impossible to use the label to index which LSP path has failed, so that the source cannot be notified.

 By analyzing the above three cases, it can be seen that, in the first case, the source end cannot use the label value of the outer label in the BDI packet sent by the sink end, and uniquely indexes to the LSP with the defect; In the third case, the sink cannot determine which LSP path is faulty according to the label value of the outer label in the packet sent by the source. Therefore, in any of the three cases, the end of the received packet cannot be received. The defective LSP is generated according to the label index in the packet sent by the peer end, so that OAM cannot be well supported. Summary of the invention

 An embodiment of the present invention provides a method, a system, a source end, and a sink end for using a label index label switching path, and one end of the received message can forward LSP according to the label index in the received message.

 Embodiments of the present invention are implemented by the following technical solutions:

An embodiment of the present invention provides a method for using a label to index a label switching path, including: receiving a message, the message carrying an operation and maintenance management label, and identifying a forward label Change the inner label of the path;

 A forward label switching path in which a defect occurs according to the inner label index.

 An embodiment of the present invention further provides a system for using a label index label switching path, including: a sending end, configured to send a message, the message carries an operation and maintenance management label, and is only used to identify a forward label switching path. Inner label

 The receiving end is configured to: when the packet arrives, a forward label switching path that is defective according to the inner label index.

 An embodiment of the present invention further provides a source end, including:

 An obtaining unit, configured to receive a reverse defect notification message sent by using a shared reverse label switching path, where the reverse defect notification message carries an operation and maintenance management label, and an inner layer for identifying a forward label switching path Label

 An index unit, configured to determine, according to the inner label, a forward label switching path in which a defect occurs. An embodiment of the present invention further provides another source, which includes:

 a constructing unit, configured to construct an operation and maintenance management message, to carry the operation and maintenance management label, and an inner label for identifying a forward label switching path;

 And a transmitting unit, configured to send, by using the label switching path, the packet constructed by the message construction unit.

 An embodiment of the present invention further provides a sink, which includes:

 a packet obtaining unit, configured to receive an operation and maintenance management packet, where the packet carries an operation and maintenance management label, and an inner label for identifying a forward label switching path;

 And a path indexing unit, configured to exchange a path according to the defect of the inner label index.

 An embodiment of the present invention further provides another sink terminal, including:

 a message construction unit, configured to construct a reverse defect notification message, such that the message carries an OAM tag, and an inner layer tag for identifying a forward label switching path in which the defect occurs;

a message transmission unit, configured to share the message construction unit by sharing a reverse label switching path The constructed message is sent out.

 It can be seen from the foregoing specific embodiments provided by the embodiments of the present invention that a defective forward LSP occurs according to an inner label index in the received packet, so in the case of sharing a reverse channel, an Mp2p LSP or a PHP, The receiving end of the packet can index the defective forward LSP according to the label carried in the packet. DRAWINGS

 1 is a schematic diagram of a format of an MPLS OAM packet provided by the prior art;

 Figure 2 is a flow chart of the first embodiment of the present invention;

 3 is a schematic diagram of a format of an OAM packet in the first embodiment of the present invention;

 Figure 4 is a flow chart of a second embodiment of the present invention;

 FIG. 5 is a schematic diagram of a format of an OAM packet according to a second embodiment of the present invention;

 Figure 6 is a flow chart of a third embodiment of the present invention. detailed description

 In the embodiment of the present invention, when a reverse channel, an Mp2p LSP, or a PHP is shared, the one end of the packet can be forwarded according to the label carried in the packet, and the Mp2p LSP can be well supported. OAM in the case of PHP or shared reverse channel, which uses the label stack technology to add an inner layer label between the outer label and the OAM label. This label is used to identify the forward (from source to sink) LSP. And by negotiating or configuring the source end and the sink end, the identifier can be recognized.

 The first embodiment provided by the present invention is the first method for using a label index label switching path, which can support OAM in the case of an Mp2p LSP. The specific implementation process of this embodiment is shown in FIG. 2, and includes:

Step S101: Each source end sends a respective OAM 4 message by using a forward LSP. Each OAM file carries an OAM tag and an inner tag that identifies the forward LSP. The format of the OAM packet is as shown in FIG. 3. It can be seen that the OAM packet includes an outer label and an OAM label, and an inner label disposed between the outer label and the OAM label. The outer label may be an MPLS label for forwarding. The inner label is used to uniquely identify a forward LSP. The OAM label may be an OAM packet with a label of 14.

 Step S102: After the OAM packet carrying the different inner label reaches the node that is aggregated by the forward LSP, the node maps the outer label to an outgoing label, and uses the outgoing label as the OAM packet. The outer label, and keep the inner label and OAM label unchanged, and then send the OAM to the text.

 The outbound label can be determined according to the LDP (Label Distribution Protocol), or can be determined according to the correspondence between the static label and the outgoing label.

 Step S103: When the 0AM packet arrives at the sink end, the sink end indexes the defective LSP according to the LSP identified by the inner layer label carried in the 0AM packet.

 Then, the sink can send a BDI packet to the source through the exclusive reverse LSP. The source can index the forward LSP that is defective according to the outer label carried in the BDI packet, and take corresponding switching measures. , to achieve OAM function.

 The sink may also send a BDI packet to the source through the shared reverse LSP. The format of the BDI packet is the same as the format of the OAM packet, and the inner label of the forward LSP needs to be carried. The inner label carried in the BDI packet can know which forward LSP is faulty, and thus take corresponding switching measures, so that the OAM function can be implemented.

 As shown in the first embodiment, when the source end sends an OAM packet, the label stacking technology separates the forwarding function from the indexing function, and the outer label serves as a forwarding function, and is responsible for the OAM packet at the source end and the sink end. Inter-transport; the inner label is indexed and is only responsible for uniquely identifying a forward LSP. Therefore, when the 0AM packet arrives at the node where the LSP is aggregated, the node converts only the outer label, and the inner label of the forward LSP remains unchanged. Therefore, the sink can be based on the inner layer. The tag is indexed to the LSP where the defect occurred.

The second embodiment provided by the present invention is a second method for using a label index label switching path. This method can support OAM in the case of PHP. The specific implementation process of this embodiment is shown in FIG. 4, and includes:

 Step S201: The source end sends an OAM packet through the forward LSP. The OAM packet carries the OAM label and the inner label used to identify the forward LSP.

 The format of the OAM packet is the same as that in the first embodiment, and includes an outer label and an OAM label, and an inner label disposed between the outer label and the OAM label. The outer label may be an MPLS label for forwarding. The inner label is only used to uniquely identify a forward LSP. The OAM tag may be an OAM^ tag with a tag of 14.

 Step S202: When the OAM packet reaches the penultimate hop node of the LSP path, the node determines to receive the OAM packet according to the outer label of the OAM packet, and carries the inner label and the OAM label. The OAM packet with the OAM payload is sent to the sink.

 The format of the OAM packet is as shown in FIG. 5, and includes an inner label and an OAM label.

 Step S203: After the OAM file arrives at the sink end, the sink end indexes the defective LSP according to the LSP identified by the inner layer label in the OAM packet.

 Then, the sink can send a BDI packet to the source through the exclusive reverse LSP. The source can index the forward LSP that is defective according to the outer label carried in the BDI packet, and take corresponding switching measures. , to achieve OAM function. The sink can also send a BDI packet to the source through the shared reverse LSP. However, the format of the BDI packet is the same as the format of the OAM packet, and the inner label of the forward LSP needs to be carried. According to the inner label carried in the BDI packet, the terminal can know which forward LSP is faulty, and accordingly take corresponding switching measures, so that the OAM function can be implemented.

It can be seen from the second embodiment that when the source end sends an OAM packet, the label stacking technology separates the forwarding function from the indexing function, and the outer label acts as a forwarding function, and is only responsible for the OAM packet at the source end and the sink end. The transfer between the inner tags is responsible for identifying the unique forward LSP. Therefore, in the case of PHP, after the outer-label is popped up in the penultimate hop of the LSP path, there is also an inner-layer label that identifies the forward LSP, so it does not affect the LSP where the sink index is defective. The third embodiment provided by the present invention is a method for using a label index label switching path, which is capable of supporting OAM in the case of sharing a reverse channel. The specific implementation process of this embodiment is shown in FIG. 6, and includes:

 Step S301: The source end sends an OAM packet. The format of the OAM message may be in the format of the prior art, or the formats in the first embodiment and the second embodiment may be used.

 Step S302: When the OAM packet arrives at the sink end, the sink end indexes the defective LSP according to the OAM packet.

 In step S302, the sink end may index the defective LSP according to the method in the prior art, or may index the defective LSP according to the methods in the first embodiment and the second embodiment.

 Step S303: After the sink index is indexed, the BDI file is sent to the source end by using the shared reverse channel, and the BDI file carries an OAM label and an inner label for identifying the forward LSP.

 The format of the BDI packet is the same as that of the OAM packet in the first embodiment, and includes an outer label and an OAM label, and an inner label disposed between the outer label and the OAM label. The outer label may be an MPLS label for forwarding. The inner label is used to identify the forward LSP. The OAM label may be an OAM packet with a label of 14.

 Step S304: When the BDI packet arrives at the source end, the source end indexes the defective LSP according to the LSP identified by the inner layer label carried by the BDI packet.

 It can be seen from the third embodiment that when the sink end determines the LSP that is defective, and sends a BDI packet through the shared reverse channel, the label stack technology is used to separate the forwarding function from the index function, and the outer label serves as a forwarding function. Responsible for the transmission of BDI packets between the sink and the source; the inner label is indexed and is responsible for identifying the forward LSP where the defect occurs. Therefore, when the BDI packet arrives at the source end, the source end can index the LSP that is defective according to the inner label, so as to obtain corresponding switching measures, so that the OAM function can be implemented.

A fourth embodiment of the present invention provides a system for using a label to index a multi-label switching path, including: a transmitting end and a receiving end. The system may further include a sink node or a penultimate hop node Or both the aggregation node and the penultimate hop node.

 The transmitting end may be a source end that sends an OAM ^ 艮 message through a forward LSP, and the corresponding receiving end may be a sink end that receives the 0 AM message.

 The sending end sends an OAM packet, where the OAM packet carries an OAM label, and an inner label that is only used to identify the forward label switching path LSP.

 The aggregation node is configured to map the outer label carried in the OAM packet to an outgoing label, and use the outgoing label as an outer label of the OAM packet, and keep the internal label. The layer label is unchanged, and the OAM packet is sent out.

 The penultimate hop node is configured to: after the OAM packet arrives, determine, according to the outer label of the OAM packet, that the OAM packet carrying the inner label is sent after receiving the OAM packet.

 The receiving end, according to the inner label index in the arrived OAM packet, has a defect positive

LSP.

 The transmitting end may be a sink that sends a BDI packet by using a shared reverse LSP, and the corresponding receiving end is a source that receives the BDI packet.

 The sending end sends a BDI packet, where the packet carries an operation and maintenance management OAM label, and an inner label that is only used to identify the forward label switching path LSP;

 The receiving end, according to the inner label index in the BDI packet that arrives, the defect is positive.

LSP.

 A fifth embodiment of the present invention provides a source end, including: an obtaining unit and an index unit.

 An acquiring unit, which receives a reverse defect notification BDI packet sent by the shared reverse LSP, where the BDI packet carries an OAM label, and an inner label used to identify the forward LSP;

 And an index unit, according to the inner label, determining a forward LSP where the defect occurs.

A sixth embodiment of the present invention further provides another source, comprising: a construction unit and a transmission unit. The construction unit, the OAM packet is configured to carry the OAM label, and the inner layer label is used to identify the forward LSP. The specific implementation process is the same as that in the method embodiment, and is not described in detail here. The transmission unit sends the packet constructed by the message construction unit through the LSP. A seventh embodiment of the present invention provides a sink, which includes: a message acquiring unit and a path indexing unit.

 The packet obtaining unit receives the OAM packet, and the packet carries an OAM label and an inner label for identifying the forward label switching path LSP.

 a path indexing unit, where a defective forward LSP occurs according to the inner label index.

 The seventh embodiment of the present invention further provides another sink, which includes: a message construction unit and a message transmission unit.

 The message construction unit constructs a reverse defect notification BDI packet, so that the packet carries an OAM label and an inner layer label for identifying a forward LSP with a defect; the specific implementation process is similar to the related description in the method embodiment. , will not be described in detail here.

 The message transmission unit sends the packet constructed by the message construction unit by sharing the reverse LSP.

 It can be seen from the specific implementation of the foregoing embodiment that the LSP of the inner layer label index between the outer label and the OAM label is defective, so that the defect can be indexed according to the label in the received message. LSP, which can support the OAM function in the case of shared reverse channel, mp2p LSP and PHP, and increases the application range of the label index.

 In addition, in the embodiment of the present invention, by setting an inner layer label between the outer label and the OAM label, it can be determined by which forward LSP the received message is transmitted, so that the correct measurement can be received within the specified time. The number of packets transmitted from a certain path, thereby reducing the occurrence of defects of dExcess, thereby reducing the occurrence of LSPs with false defects.

Those of ordinary skill in the art will appreciate that all or part of the steps in implementing the above-described embodiments may be performed by program-related hardware. The software corresponding to the embodiment can be stored in a computer readable storage medium such as ROM/RAM, disk, optical disk, and the like. The spirit and scope of the invention. Thus, if such modifications and variations of the present invention are claimed in the present invention The invention is also intended to cover such modifications and variations within the scope of the invention.

Claims

Claim A method for using a label index label switching path, the method comprising: receiving a message, the message carrying an operation and maintenance management label, and an inner label for identifying a forward label switching path;  A forward label switching path in which a defect occurs according to the inner label index.  2. The method of using a label index label switching path according to claim 1, wherein the text further carries an outer label for forwarding.  The method of using the label index label switching path according to claim 2, wherein the message comprises: an operation and maintenance management message sent by using a forward label switching path.  4. The method of using a label index label switching path according to claim 3, further comprising:  After receiving the multiple operation and maintenance management packets, the node that maps the forward label switching path maps the outer label to an outgoing label, and uses the outgoing label as the outer layer of the operation and maintenance management packet. Label, and keep the inner label unchanged, and then send the operation and maintenance management message.  The method of using a label index label switching path according to claim 3, further comprising:  When the operation and maintenance management packet reaches the penultimate hop node of the forward label switching path, the penultimate hop node determines to receive the operation and maintenance management packet according to the outer label, and carries the inner label. The operation and maintenance management message is sent out.  The method of using a label index label switching path according to claim 1 or 2, wherein the message comprises: a reverse defect notification message sent by sharing the reverse label switching path.  A system for using a tag index multi-label switching path, comprising: a sending end, configured to send a message, the message carrying an operation and maintenance management label, and only identifying a forward label switching path. Inner label a receiving end, configured to: when the message arrives, according to the inner label index, a defect is positive Label exchange path.  The system of claim 7, wherein the transmitting end comprises: sending, by the forward label switching path, a source end of the operation and maintenance management message, and the corresponding receiving end The terminal includes: a sink that receives the operation and maintenance management message.  9. The system of claim 7, wherein the method further comprises:  The aggregation node is configured to map the outer label carried in the operation and maintenance management packet to an outgoing label, and use the outgoing label as an outer layer of the operation and maintenance management packet. The label, and keep the inner label unchanged, and send the operation and maintenance management message.  10. The system of claim 7, wherein the tag indexing multi-label switching path is further characterized by:  The penultimate hop node is configured to: after the operation and maintenance management packet arrives, determine to receive the operation and maintenance management packet according to the outer label, and send the operation and maintenance management packet carrying the inner label.  11. The system for tagging a multi-label switched path according to claim 7, wherein:  The transmitting end includes: a sink that sends a reverse defect notification message by using a shared reverse label switching path, where the corresponding receiving end includes: receiving the source end of the reverse defect notification message.  12. A source end, characterized by comprising:  An obtaining unit, configured to receive a reverse defect notification message sent by using a shared reverse label switching path, where the reverse defect notification message carries an operation and maintenance management label, and an inner label used to identify the forward label switching path ;  An index unit, configured to determine, according to the inner label, a forward label switching path in which a defect occurs. 13. A source end, characterized in that: a constructing unit, configured to construct an operation and maintenance management message, to carry the operation and maintenance management label, and an inner label for identifying a forward label switching path; a transmitting unit, configured to send, by using a label switching path, a packet constructed by the message construction unit.  14. A sink terminal, characterized by comprising:  a message obtaining unit, configured to receive an operation and maintenance management message, where the message carries an operation and maintenance management label, and an inner layer label for identifying a forward label switching path;  a path indexing unit, configured to forward a defect based on the inner label index. 15. A sink terminal, characterized by comprising:  a message construction unit, configured to construct a reverse defect notification message, such that the message carries an operation and maintenance management label, and an inner label for identifying a forward label switching path where the defect occurs;  The message transmission unit is configured to send the packet constructed by the message construction unit by sharing the reverse label switching path.