CN101986622B - A kind of automatic identifying method of PCE status attribute and system - Google Patents

Abstract

The invention discloses a method for automatically identifying PCE state attributes. A path computation unit (PCE) adds the state attribute representation capability of the PCE to the automatic discovery information, and the PCE diffuses and propagates the state of the PCE through the flooding mechanism of the link state routing protocol. Attribute: the control plane node receives the automatic discovery information through the link state routing protocol, and identifies the state attribute of the PCE by parsing and comparing the automatic discovery information. The invention also discloses an automatic identification system of PCE state attributes, the identification unit in the system is used to control plane nodes to receive automatic discovery information through the link state routing protocol, and to identify the PCE by analyzing and comparing the automatic discovery information the status attribute. By adopting the method and system of the present invention, the PCE state attribute can be automatically identified by the PCE automatic discovery mechanism.

Description

A method and system for automatic identification of PCE state attributes

technical field

The present invention relates to the control technology of Path Computation Element (PCE, Path ComputationElement) in intelligent bearer network, especially relates to a kind of automatic identification method and system of PCE status attribute.

Background technique

With the rapid growth of IP services, the demand for network bandwidth is not only increasing, but also due to the uncertainty and unpredictability of IP traffic itself, the demand for dynamic allocation of network bandwidth is becoming more and more urgent. The traditional original method, which mainly relies on manually setting network connections, is time-consuming, labor-intensive and error-prone. It is not only difficult to adapt to the needs of modern networks and new business expansion, but also difficult to meet the needs of market competition. A new network concept that can automatically complete network connections - Automatically Switched Optical Network (named ASON in ITU-T SG15) came into being. This is a network that uses an independent ASON control plane to implement automatic connection management through various transport networks (including SDH, PTN or OTN). This optical network with an independent control plane is called an intelligent optical network.

The intelligent optical network has the function of automatic discovery, including the ability to automatically discover changes in services, topology, and resources; it has powerful computing functions, and can perform calculations, analysis, reasoning, and judgments based on these changes in the network environment, and effectively allocate resources according to this The principle finally makes the decision; it has the ability to establish fast and dynamic connections, and can provide protection and recovery functions for the required services; it can provide different types of services with different priorities, etc.

With the development of Multi-Protocol Label Switching (MPLS)/General Multi-Protocol Label Switching (GMPLS) networks, the network topology is becoming more and more complex, the amount of routing is very large, and the path calculation is becoming more and more complicated. The deployment of traffic engineering requires network devices to calculate routes under complex constraints. These constraints include not only static constraints, such as the distance between router nodes, bandwidth, and line capacity of optical network equipment, but also dynamic constraints. Conditions, such as network failure status, network congestion information, etc. Constraint-based path calculation is a basic functional module in MPLS/GMPLS network traffic engineering, especially in large-scale multi-domain multi-level MPLS/GMPLS networks, for a large number of paths and complex constraints, traffic engineering requires Path computation requires the coordination of different network domains and special computation functions. For example, in an n-node single-domain single-level fully interconnected network, the number of paths in the network is n×(n-1)/2, in order to recover quickly through traffic engineering in the event of network failure or abnormal network traffic changes Or dredging the network business, it is required that the network equipment at the faulty node or the input node of the abnormal traffic calculate the best recovery or detour path in the shortest possible time according to various constraints. The shortening of the calculation time means the improvement of the recovery speed. The best path means the improvement of network utilization efficiency. This complex calculation often requires the understanding of the global topology and constraints of the network, and requires a large amount of CPU computing resources to run complex algorithms. When a large amount of CPU resources are used for path calculation During the middle period, it has a certain impact on the stability of network equipment and the stability of the entire network, all of which are a great challenge to network equipment.

In order to solve this problem, the IETF PCE working group proposed a PCE-based MPLS/GMPLS network structure. In this structure, PCE is a functional entity responsible for path calculation in the network. It is based on known network topology and constraints. According to the request of the path calculation client, an optimal path that satisfies the constraints is calculated. The PCE can be located anywhere in the network, and can be integrated inside a network device, for example, inside a Label Switching Router (LSR), or it can be an independent device. Path Computation Clients (PCC, Path Computation Clients) and PCE, and between PCE and PCE communicate through a special path computation protocol (PCE Communication Protocol), submit path computation requests and obtain path computation results. The PCC can be an LSR or a network management system (NMS) in the MPLS/GMPLS network.

According to the definition of RFC 4655, PCE can be divided into stateful and stateless. The stateless PCE only uses the information in the traffic engineering database (TED) for path calculation, while the stateful PCE is not only based on the topology information in the traffic engineering database (TED), but also uses the existing paths and Information about occupied resources. Since the stateful PCE has more information, on the one hand, it has stronger path calculation capability than the stateless PCE. Under the same conditions, the stateful PCE should be preferred. In some cases, even the stateful PCE can only be used for path calculation; on the other hand On the one hand, the synchronization of resource information has additional requirements different from stateless PCE. Therefore, the state attribute of PCE (that is, whether the PCE is a stateful PCE) must be recognized by the PCC and other PCEs in the domain. See the following Scenario description:

Scenario 1: Synchronization between the control plane and the PCE. The stateful PCE needs to save the path information of existing services in the live network, so when the service state changes (establishment, deletion), the service change information must be synchronized to the stateful PCE in time. To achieve this purpose, the control plane node needs to identify the status attribute of the PCE that has a session relationship with itself.

Scenario 2: Synchronization between PCEs in a single-domain multi-PCE scenario. In the case of a session relationship with the control plane, the stateful PCE ensures the accuracy of its own state information through a synchronization mechanism with the control plane nodes. When there are multiple PCEs in the domain, it cannot be guaranteed that all PCEs and all control plane nodes maintain normal session relationships at any time. To this end, it is necessary to establish a synchronization relationship between stateful PCEs. When a PCE is notified of a service state change, it should spread this information to adjacent stateful PCEs in time to ensure the consistency of service states of all stateful PCEs in the domain. and correctness, that is, when there are multiple PCEs in the domain, the stateful PCEs need to recognize each other's state attributes to establish a state synchronization relationship.

Scenario 3: Stateful PCEs are preferred. Since the path calculation quality of the stateful PCE is better than that of the stateless PCE, the PCC should preferentially select the stateful PCE for path calculation under the same conditions. Therefore, when the PCC knows the state attribute of the PCE, it can purposely select the stateful PCE for path calculation, so as to obtain a more ideal path calculation result.

From the functional requirements of the above scenarios, it can be seen that the control plane nodes and other stateful PCEs in the domain need to be able to identify the state attributes of the PCE in order to realize the stateful PCE function. Based on the above description, it can be known that, as an important attribute of the PCE, the status attribute of the PCE should be recognized by the PCC and other PCEs in a timely and accurate manner.

As part of the automatic discovery mechanism of the control plane, the automatic discovery mechanism of the PCE is used to make the PCC aware of its existence and capability attributes. In order to support the automatic discovery of PCE, the PCE working group expanded the relevant routing protocols and added a TLV called PCE Discovery (PCE Discovery TLV). This TLV is used to flood the PCE information to the entire domain to inform members in the domain of the relevant information of the PCE, such as the location of the PCE, the scope of PCE path calculation (inter-domain, AS inter-domain, cross-network layer, etc.), for one or more Information such as the visibility of PCEs in a domain, adjacent PCEs, communication capabilities, and path computation capabilities.

A PCED TLV consists of a series of sub-TLVs, and sub-TLVs can be placed in a PCED TLV in any order. When the Open Shortest Path First (OSPF) routing protocol is used, the defined sub-TLVs are shown in Table 1 below:

Sub-TLV type length name 1 lengthen PCE-ADDRESS sub-TLV 2 4 PATH-SCOPE sub-TLV 3 4 PCE-DOMAIN sub-TLV 4 4 NEIG-PCE-DOMAIN sub-TLV 5 lengthen PCE-CAP-FLAGS sub-TLV

Table 1

When the intermediate system to intermediate system (IS-IS) routing protocol is used, the defined sub-TLVs are shown in Table 2 below:

Sub-TLV type length name 1 lengthen PCE-ADDRESS sub-TLV 2 3 PATH-SCOPE sub-TLV 3 lengthen PCE-DOMAIN sub-TLV 4 lengthen NEIG-PCE-DOMAIN sub-TLV 5 lengthen PCE-CAP-FLAGS sub-TLV

Table 2

The fifth type of sub-TLV is used to represent the capability information of the PCE, which is an optional sub-TLV. There can be at most one PCE-CAP-FLAGS sub-TLV in one PCEDTLV. If there are multiple entries, only the first entry is valid. The PCE-CAP-FLAGS sub-TLV format is shown in Figure 1, where the value of Type (Type) is 5, the value of Length (Length) is a multiple of 4, and PCE Capability Flags represents the PCE capability flag.

The following identification bits are defined in the PCE capability identification bit (the identification bit numbers are from high to low), as shown in Table 3 below:

BIT ability 0 Path Computation Considering GMPLS Link Constraints 1 Bi-directional path calculation 2 Separation path calculation 3 Load sharing path calculation 4 Synchronous path calculation 5 Support multi-objective path calculation 6 Support additional path constraints (such as maximum hops) 7 Support the priority of path calculation requests 8 Support one message to carry multiple path calculation requests 9～31 Reserved flag, set to 0

table 3

Since the PCE status attribute (that is, whether it is a stateful PCE) is not identified in the capability identification bit, the outside world has no way of automatically identifying the PCE status attribute by the PCE automatic discovery mechanism, that is, automatically identifying whether a PCE is a stateful PCE. It affects scenarios such as PCC selection of PCE and synchronization between stateful PCEs. There is an urgent need for an automatic identification scheme of PCE state attributes.

Contents of the invention

In view of this, the main purpose of the present invention is to provide a method and system for automatically identifying PCE status attributes, which can automatically identify PCE status attributes through a PCE automatic discovery mechanism.

In order to achieve the above object, technical solution of the present invention is achieved in that way:

A method for automatically identifying PCE state attributes, the method comprising: a path computation element (PCE) adds the state attribute representation capability of the PCE to the automatic discovery information, and the PCE diffuses and propagates the state of the PCE through the flooding mechanism of the link state routing protocol Attribute: the control plane node receives the automatic discovery information through the link state routing protocol, and identifies the state attribute of the PCE by analyzing and comparing the automatic discovery information.

Wherein, the method further includes: the control plane node triggers state synchronization between the control plane node and the stateful PCE according to the identified state attribute of the PCE.

Wherein, when the state attribute of the PCE indicates that the capability is in the form of a capability flag, the control plane node identifying the state attribute of the PCE specifically includes: if the state attribute capability flag in the automatic discovery information of PCE flooding bit to identify the PCE as a stateful PCE, and after receiving the auto-discovery information flooded by the PCE, the control plane node recognizes that the state attribute of the PCE is Stateful PCEs.

Wherein, the triggered state synchronization between the control plane node and the stateful PCE specifically includes: when the connection state transmission changes, the control plane node notifies the change of the connection state with itself and recognizes the state attribute of the PCE Perform state synchronization for the PCE of the stateful PCE;

Wherein, the connection state includes: the control plane node has a new connection established, or the control plane node has a connection deleted.

Wherein, the method further includes: the control plane node triggers state synchronization between stateful PCEs according to the identified state attributes of the PCEs.

Wherein, when the state attribute of the PCE indicates that the capability is in the form of a capability flag, the control plane node identifying the state attribute of the PCE specifically includes: if the state attribute capability flag in the automatic discovery information of PCE flooding bit to identify the PCE as a stateful PCE, and after receiving the auto-discovery information flooded by the PCE, the control plane node recognizes that the state attribute of the PCE is Stateful PCEs.

Among them, the state synchronization between the triggered stateful PCEs specifically includes: establishing a state synchronization relationship between the PCEs whose state attributes of the identified PCEs are stateful PCEs; Notify the PCE that has a session relationship with itself and recognizes that the state attribute of the PCE is a stateful PCE, and perform state synchronization; according to the state synchronization relationship established between the PCEs, it is known that the PCE that needs to perform state synchronization will change the connection state, and notify it to establish PCE of the state synchronization relationship;

Wherein, the connection state includes: the control plane node has a new connection established, or the control plane node has a connection deleted.

An automatic identification system of PCE state attributes, the system includes: an identification unit, used for the PCE to add the state attribute representation capability of the PCE in the automatic discovery information, and the PCE diffuses and propagates the state of the PCE through the flooding mechanism of the link state routing protocol In the case of attributes, the control plane node receives the automatic discovery information through the link state routing protocol, and identifies the status attribute of the PCE by analyzing and comparing the automatic discovery information.

Wherein, the system further includes: a first state synchronization unit, configured for the control plane node to trigger state synchronization between the control plane node and the stateful PCE according to the identified state attribute of the PCE.

Wherein, the system further includes: a second state synchronization unit, configured to control plane nodes to trigger state synchronization between stateful PCEs according to the identified state attributes of the PCEs.

The PCE of the present invention adds the state attribute representation capability of the PCE to the automatic discovery information, and the PCE diffuses and propagates the state attribute of the PCE through the flooding mechanism of the link state routing protocol; the control plane node receives the automatic discovery information through the link state routing protocol , identify the status attribute of the PCE by analyzing and comparing the auto-discovery information.

By adopting the present invention, the expressive ability of the PCE state attribute is increased, the PCE state attribute is propagated, and the stateful PCE is finally identified by comparing the PCE state attribute. Therefore, the PCE status attribute can be automatically identified by the PCE automatic discovery mechanism.

Description of drawings

Fig. 1 is the PCE-CAP-FLAGS sub-TLV structure schematic diagram that the present invention relates to;

FIG. 2 is a schematic diagram of an implementation flow of Embodiment 1 of the present invention;

FIG. 3 is a schematic diagram of an implementation flow of Embodiment 2 of the present invention.

Detailed ways

The basic idea of the present invention is: the PCE adds the state attribute representation capability of the PCE in the automatic discovery information, and the PCE diffuses and propagates the state attribute of the PCE through the flooding mechanism of the link state routing protocol; To the automatic discovery information, the status attribute of the PCE is identified by analyzing and comparing the automatic discovery information.

The implementation of the technical solution will be further described in detail below in conjunction with the accompanying drawings.

The solution of the present invention increases the state attribute representation capability of PCE (for example, the PCE state attribute can be identified in the mode of capability identification bit), and the state attribute of PCE (that is, whether it is a stateful PCE) is propagated to PCE through the PCE automatic discovery mechanism The PCC and other PCEs finally compare the state attributes of the PCE to identify the stateful PCE, thereby realizing the automatic identification function of the stateful PCE.

An automatic identification method of a PCE state attribute, the method mainly includes the following contents:

1. The present invention expands the existing PCE-CAP-FLAGS sub-TLV, and adds the following content in its capability identification bit:

BIT ability 9 Stateful PCE

In the expanded PCE-CAP-FLAGS sub-TLV, the following flags are defined in the PCE capability flags (the flags are numbered from high to low), as shown in Table 4 below:

BIT ability 0 Path Computation Considering GMPLS Link Constraints 1 Bi-directional path calculation 2 Separation path calculation 3 Load sharing path calculation 4 Synchronous path calculation 5 Support multi-objective path calculation 6 Support additional path constraints (such as maximum hops) 7 Support the priority of path calculation requests 8 Support one message to carry multiple path calculation requests 9 Stateful PCE (new content of the present invention) 10～31 Reserved flag bit, set to 0

Table 4

Two, the implementation steps of the present invention are as follows:

1. The PCE adds the expressive capability of the state attribute of the PCE to the automatic discovery information to indicate the state attribute of the PCE itself (that is, whether the PCE is a stateful PCE).

Here, the status attribute of the PCE can be represented by the PCED TLV, and the status attribute of the PCE can be carried by the PCE-CAP-FLAGSsub-TLV.

2. The PCE diffuses and disseminates the state attributes of the PCE through the flooding mechanism of the link state routing protocol.

3. A control plane node such as the PCC receives the auto-discovery information through the link state routing protocol, and the auto-discovery information includes the status attribute of the PCE.

4. The control plane node, such as the PCC, can analyze the status attribute of the PCE according to the pre-determined protocol, and identify the status attribute of the PCE after comparing the status attributes.

5. A control plane node such as the PCC triggers other functions according to the status attribute of the PCE.

Here, other functions to be triggered include: 1) applying the present invention to perform state synchronization between control plane nodes and stateful PCEs; and 2) applying the present invention to perform state synchronization between stateful PCEs.

To sum up, the implementation of the present invention mainly includes steps such as identification, dissemination, and identification of PCE status attributes. Specifically, for the identification, the identification of the PCE status attribute is realized by extending the PCE-CAP-FLAGS sub-TLV. By increasing the PCE capability identification bit in the PCE-CAP-FLAGS sub-TLV (BIT position 9 increases the PCE status attribute identification bit), so that the PCE-CAP-FLAGS sub-TLV has the PCE status attribute representation of whether the PCE is a stateful PCE capabilities, as shown in Figure 1 and Table 4. For dissemination, the dissemination of PCE state attributes is carried out through the flooding mechanism of the link state routing protocol. For identification, the identification of PCE status attributes is completed by parsing and comparing PCE-CAP-FLAGS sub-TLV. It can be seen that compared with the prior art, the present invention enables the outside world to know whether a PCE is the capability attribute information of a stateful PCE through the PCE automatic discovery mechanism by expanding the capability identification bit of the PCE-CAP-FLAGS sub-TLV, thereby improving path calculation Quality and efficiency, and enhance the flexibility of implementing other functions based on the stateful PCE, for example: make the selection of the PCE by the PCC more targeted, and simplify the PCE state synchronization process.

The present invention is described with examples below.

Embodiment 1: State synchronization between the control plane node and the stateful PCE (that is, the above scenario 1).

As shown in Figure 2, this embodiment includes the following steps:

Step 101, PCE-A floods the automatic discovery information. The state attribute representation capability of the PCE is added to the automatic discovery information, specifically, the PCE state attribute identifier is carried in the automatic discovery information, and the identifier is used to identify "PCE-A is a stateful PCE".

Step 102, the control plane node receives the automatic discovery information of PCE-A flooding, and according to the definition of relevant bits in the PCE-CAP-FLAGS sub-TLV in the automatic discovery information, recognizes that the state attribute of PCE-A is stateful PCE.

Step 103, the control plane node initiates to establish a PCEP session with PCE-A (here only the case of PCC initiating a session is considered).

Step 104, the PCEP session with PCE-A is established successfully.

Step 105, PCE-B floods the automatic discovery information, and the PCE status attribute is marked as "stateless PCE".

Step 106, the control plane node receives the automatic discovery information of PCE-B flooding, and according to the definition of relevant bits in the PCE-CAP-FLAGS sub-TLV in the information, recognizes that the state attribute of PCE-B is a stateless PCE.

Step 107, the control plane node initiates the establishment of a PCEP session with the PCE-B (here only considers the case where the PCC initiates the session).

Step 108, the PCEP session with PCE-B is established successfully.

Step 109, the control plane node has a new connection established.

Step 110 , the control plane node notifies the stateful PCE of the new connection establishment information with itself, and the reason is that PCE-A is a stateful PCE, so it notifies PCE-A. PCE-B is a stateless PCE, so it is not notified.

Step 111, PCE-A adds connection path state information according to the notification message.

Step 112, the connection of the control plane node is deleted.

Step 113 , the control plane node notifies the stateful PCE that has a session relationship with itself of the connection deletion information. The reason is that PCE-A is a stateful PCE, so it notifies PCE-A. PCE-B is a stateless PCE, so it is not notified.

Step 114, PCE-A deletes the connection path state information according to the notification message.

Among the above steps, step 101, step 102, step 105, step 106, step 109, step 110-step 114 are particularly critical.

Embodiment 2: state synchronization among stateful PCEs (that is, the above-mentioned scenario 2).

As shown in Figure 3, this embodiment includes the following steps:

Step 201, PCE-A floods the automatic discovery information. The state attribute representation capability of the PCE is added to the automatic discovery information, specifically, the PCE state attribute identifier is carried in the automatic discovery information, and the identifier is used to identify "PCE-A is a stateful PCE".

Step 202, the control plane node a receives the automatic discovery information of PCE-A flooding, and according to the definition of relevant bits in the PCE-CAP-FLAGS sub-TLV in the information, recognizes that the state attribute of PCE-A is a stateful PCE .

Step 203, the control plane node a initiates the establishment of a PCEP session with PCE-A (here only the case of PCC initiating a session is considered).

Step 204, the PCEP session between control plane node a and PCE-A is established successfully.

Step 205, PCE-B floods the automatic discovery information.

Step 206, the control plane node b receives the automatic discovery information of PCE-B flooding, and according to the definition of relevant bits in the PCE-CAP-FLAGS sub-TLV in the information, recognizes that the status attribute of PCE-B is a stateful PCE .

Step 207, the control plane node b initiates the establishment of a PCEP session with PCE-B (here only the case of PCC initiating a session is considered).

Step 208, the PCEP session between control plane node b and PCE-B is established successfully.

Step 209, PCE-B receives the automatic discovery information flooded by PCE-A, and recognizes that the status attribute of PCE-A is a stateful PCE according to the definition of relevant bits in the PCE-CAP-FLAGS sub-TLV in the information.

Step 210, PCE-B initiates to establish a PCEP session with PCE-A (here only considers the case where PCE-B actively initiates the session).

Step 211, the establishment of the PCEP session between PCE-A and PCE-B is completed.

Step 212, since PCE-A is a stateful PCE, PCE-B initiates establishment of a state synchronization relationship with PCE-A.

Step 213, the state synchronization relationship from PCE-B to PCE-A is established successfully.

Step 214, PCE-A receives PCE-B flooded automatic discovery information, and according to the definition of relevant bits in the PCE-CAP-FLAGS sub-TLV in the information, recognizes that the state attribute of PCE-B is a stateful PCE.

Step 215. Since PCE-B is a stateful PCE, PCE-A initiates establishment of a state synchronization relationship with PCE-B.

Step 216, the state synchronization relationship from PCE-A to PCE-B is established successfully.

Step 217, the control plane node a changes (establishes or deletes) the connection state.

Step 218 , the control plane node a notifies the stateful PCE of the connection state change information with itself, and PCE-A is a stateful PCE, so it notifies PCE-A. PCE-B has no session relationship with node a, so it cannot be notified.

Step 219, PCE-A updates the connection path state information according to the connection state change notification message.

Step 220, since there is a state synchronization relationship from PCE-A to PCE-B, PCE-A notifies PCE-B of state change information.

Step 221, PCE-B updates the connection path state information according to the connection state change notification message.

Step 222, the control plane node b undergoes a connection state change (establishment or deletion).

Step 223 , the control plane node b notifies the stateful PCE of the connection state change information with itself, and PCE-B is a stateful PCE, so it notifies PCE-B. PCE-A has no session relationship with node b, so it cannot be notified.

Step 224, PCE-B updates the connection path state information according to the connection state change notification message.

Step 225 , since there is a state synchronization relationship from PCE-B to PCE-A, PCE-B notifies PCE-A of state change information.

Step 226, PCE-A updates the connection path state information according to the connection state change notification message.

Among the above steps, step 201, step 202, step 206, step 209, step 212-step 226 are particularly critical.

An automatic identification system of PCE state attributes, the system includes: identification unit, the identification unit is used for PCE to add the state attribute representation capability of PCE in the automatic discovery information, and the PCE diffuses and propagates the PCE through the flooding mechanism of the link state routing protocol In the case of the status attribute of the PCE, the control plane node receives the automatic discovery information through the link state routing protocol, and identifies the status attribute of the PCE by analyzing and comparing the automatic discovery information.

Here, the system further includes: a first state synchronization unit, configured for the control plane node to trigger state synchronization between the control plane node and the stateful PCE according to the identified state attribute of the PCE.

Here, the system further includes: a second state synchronization unit, the second state synchronization unit is used for the control plane node to trigger state synchronization between stateful PCEs according to the identified state attributes of the PCEs.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention.

Claims (8)

1. the automatic identifying method of a PCE status attribute, it is characterized in that, the method comprises: the status attribute that path-calculating element (PCE) adds PCE in automatic discovery information represents ability, the flooding mechanism diffusion of PCE by link-state routing protocol and the status attribute of propagation PCE; Control plane node receives described automatic discovery information by link-state routing protocol, by identifying the status attribute of described PCE to the analysis and comparison of automatic discovery information; Control plane node according to the status attribute of the described PCE identified, trigging control plane node and have state synchronized between state PCE; PCE increases or deletes or upgrade access path state information.

2. method according to claim 1, it is characterized in that, when the status attribute of described PCE represents the form of ability employing ability label position, described in described control plane node recognition, the status attribute of PCE specifically comprises: if the status attribute ability label position in the described automatic discovery information that floods of PCE, identify described PCE for there being state PCE, after then control plane node receives the described automatic discovery information that PCE floods, according to the status attribute ability label position carried in automatic discovery information, identify the status attribute of described PCE for there being state PCE.

3. method according to claim 2, it is characterized in that, trigger control plane node and have the state synchronized between state PCE specifically to comprise: when connection status send change time, described control plane node is by the change of connection status, notice has session relationship with oneself and the status attribute identifying PCE is the PCE having state PCE, carries out state synchronized;

Wherein, described connection status comprises: control plane node has new connection establishment or control plane node to have connection deleted.

4. method according to claim 1, is characterized in that, the method also comprises: control plane node, according to the status attribute of the PCE identified, triggers the state synchronized had between state PCE.

5. method according to claim 4, it is characterized in that, when the status attribute of described PCE represents the form of ability employing ability label position, described in described control plane node recognition, the status attribute of PCE specifically comprises: if the status attribute ability label position in the described automatic discovery information that floods of PCE, identify described PCE for there being state PCE, after then control plane node receives the described automatic discovery information that PCE floods, according to the status attribute ability label position carried in automatic discovery information, identify the status attribute of described PCE for there being state PCE.

6. method according to claim 5, is characterized in that, the state synchronized between state PCE that has of triggering specifically comprises: all set up state synchronized relation for having between the PCE of state PCE in the status attribute identifying PCE; When connection status sends change, control plane node is by the change of connection status, and notice has session relationship with oneself and the status attribute identifying PCE is the PCE having state PCE, carries out state synchronized; According to the state synchronized relation set up between PCE, know the change of PCE by connection status need carrying out state synchronized, notice sets up the PCE of state synchronized relation with it;

Wherein, described connection status comprises: control plane node has new connection establishment or control plane node to have connection deleted.

7. the automatic recognition system of a PCE status attribute, it is characterized in that, this system comprises: recognition unit, the status attribute of adding PCE for PCE in automatic discovery information represents ability, when PCE is spread by the flooding mechanism of link-state routing protocol and is propagated the status attribute of PCE, control plane node receives described automatic discovery information by link-state routing protocol, by identifying the status attribute of described PCE to the analysis and comparison of automatic discovery information; PCE increases or deletes or upgrade access path state information;

First state synchronized unit, for the status attribute of control plane node according to the described PCE identified, trigging control plane node and have state synchronized between state PCE.

8. system according to claim 7, is characterized in that, this system also comprises: the second state synchronized unit, for the status attribute of control plane node according to the PCE identified, triggers the state synchronized had between state PCE.