WO2008031337A1

WO2008031337A1 - A traffic engineering path computation method, a system and a path computation element

Info

Publication number: WO2008031337A1
Application number: PCT/CN2007/070227
Authority: WO
Inventors: Renhai Zhang
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2006-09-07
Filing date: 2007-07-03
Publication date: 2008-03-20
Also published as: CN101141376A; CN101141376B

Abstract

A traffic engineering path computation method, a system and a path computation element. By using the technical solution that a path computation element locally saves the path computation result in the own autonomous system and the entry node address and the path computation element address in the neighbored downstream autonomous system, and informs the neighbored upstream autonomous system of nothing but the address of itself and the entry node address of the own autonomous system during the traffic engineering path computation process, the address of the path computation element in one autonomous system is known only by the neighbored upstream autonomous system, and doesn't be spread to all the upstream autonomous systems.

Description

Method and system for calculating traffic engineering path and path computing device

Technical field

The present invention relates to the field of network communication technologies, and in particular, to a method and system for calculating a traffic engineering path and a path computing device. Background of the invention

Traffic Engineering (TE) focuses on the optimization of overall network performance, measuring, modeling, describing and controlling network traffic according to certain principles to achieve specific performance goals. The performance goal that traffic engineering wants to achieve is divided into two levels: one is traffic-oriented, that is, how to improve the service quality of the network; the second is resource-oriented, that is, how to optimize the use of network resources, the most important of which is bandwidth resources. Effective use. With the continuous development of network technologies and the mature technology of General Multiple Protocol Label Switch (GMPLS), inter-domain traffic engineering will cover GMPLS networks and span different carrier networks.

Constraint-based Shortest Path First (CSPF) algorithm is an important part of traffic engineering. The path calculation between Autonomous System (AS) is very complicated and may require calculation of different autonomous systems. Entities collaborate and work together. The path calculation method based on the Path Computation Element (PCE) model can be applied to traffic engineering between different network domains. The calculation method does not affect the use of calculated paths, such as Label Switch Path (LSP). ) establishment, maintenance and demolition.

In the path calculation method based on the PCE model, when the client device (PCC, Path Computation Client) requesting the path calculation needs to establish an LSP path, the calculation request information is sent to the PCE, and the request information includes the destination of the path and various constraints. Basic conditions After receiving the request information, the PCE calculates a path that satisfies the constraint condition in the request information according to the topology synchronized with the network and the Traffic Engineering Database (TED), and returns the response message to the response message. PCC. As an explicit path object (ERO) parameter for establishing an LSP, the foregoing calculation result may include an exact node and a loose node, where the precise node is a specific router, and the loose node is a network segment, or a region. Or an autonomous system. The calculation range that a PCE is responsible for is generally an autonomous system. When the destination of the calculation request information is another autonomous system, PCE collaboration between different autonomous systems is required to complete the calculation of a path.

In the path calculation method based on the PCE model, there are two basic protocols: the PCE discovery protocol and the PCE communication protocol. The PCE discovery protocol is responsible for discovering the existence and computing power of the PCE and transmitting corresponding information to the PCC that initiates the path calculation request, and the PCC selects an appropriate PCE according to the information sent by the protocol and sends a calculation request to the path calculation; PCE communication The protocol is mainly responsible for transmitting calculation request and response information between the PCC and the PCE. The calculation request message sent by the PCC to the PCE includes the unique identification number and various constraints of the current calculation. When a PCE calculation requires other PCEs. This communication protocol support is also required between PCEs when assisting.

One of the main applications of PCE is to implement the calculation of MPLS TE paths between autonomous systems. Each autonomous system is responsible for the path calculation within the autonomous system by its respective PCE. When a path needs to span multiple autonomous systems, the PCE in each autonomous system passes the calculation request and the result one by one through the PCE communication protocol.

FIG. 1 is a schematic diagram of establishing a TE path between two autonomous systems in the prior art. As shown in Figure 1, AS 100 and AS 200 are two different autonomous systems. When Router A in AS 100 needs to establish a TE path to Router B in AS 200: Router A first sends a path calculation request to the path calculation device PCE1 in its AS 100; PCE1 receives the calculation. After the request, the request is passed to the AS through the PCE communication protocol. PCE2 in 200; PCE2 calculates all paths from AS 100 to Router B, and returns the result to PCE1 through PCE communication protocol; PCE1 calculates all paths from Router A to Router B based on the result returned by PCE2, and selects one from it. The optimal path is returned to Router A through the PCE communication protocol. At this time, Router A can establish a TE path from Router A to Router B through the communication signaling protocol. The process when path computation needs to span more autonomous systems can be derived from the example shown in Figure 1, and will not be repeated here.

Different autonomous systems spanned by a TE path can belong to the same carrier or different operators. When crossing the autonomous systems of different operators, the network topology between operators is considered for security reasons. Node information needs to be isolated. However, in FIG. 1, if the AS 100 and the AS 200 belong to different operators, in the above calculation process, when the PCE2 returns the calculation result to the PCE1, it includes the node of the AS 200 and part of the topology information, and the The information is not allowed to be obtained by Router A and is used as a parameter when establishing a path. In this case, when the router A establishes a path through the signaling protocol, the explicit path object ERO parameter cannot contain the node information in the AS 200, but according to the current letter. Order the agreement, such a path cannot be established.

In order to solve the above problem, the IETF standards organization proposes a PKS (Path Key Solution) scheme, in which: each PCE responsible for calculating the TE path across the autonomous system passes each of the calculated paths within the local autonomous system. The node information is mapped to a path index, and the path index and its own address information are returned to the PCE in the upstream autonomous system as a calculation result, and the true calculation result, that is, the node information of the path in the local autonomous system is each The PCE is stored locally, so that the local node information is not spread to other operators' networks. When the path is established, the resource reservation protocol-based traffic reservation (RSVP-TE) The address information of the path I and PCE is taken as the ERO parameter. When the signaling message established by the path reaches the next autonomous system, the first router in the next autonomous system that receives the message parses the ERO field to obtain the corresponding ETO. After the PCE address and path index information of the autonomous system, the road will be The path index is sent to the PCE in the autonomous system, and the PCE is requested to return the stored node information corresponding to the path index; the router inserts the node information returned by the PCE into the ERO parameter of the signaling message, and executes in the local autonomous system. The path is established until the signaling message established by the path is transmitted to the next autonomous system. By analogy, the above steps are also performed in the next autonomous system until the entire path is established.

However, in the process of implementing the present invention, the inventors found that in the above PKS scheme, although the calculation results are isolated among the autonomous systems, the PCE address information is spread to all upstream autonomous systems. Summary of the invention

The embodiment of the invention provides a method for calculating a traffic engineering path, which makes the PCE address not spread to all upstream autonomous systems during the path calculation process.

The embodiment of the invention provides a system for calculating a traffic engineering path, which makes the PCE address not spread to all upstream autonomous systems during the path calculation process.

The embodiment of the present invention further provides a PCE, which makes the PCE address not spread to all upstream autonomous systems during the path calculation process.

In order to achieve the above object, the technical solution of the present invention is specifically implemented as follows:

The embodiment of the invention discloses a method for calculating a traffic engineering path, the method comprising: calculating, by the path computing device PCE in the most downstream autonomous system where the destination node is located, the path in the local autonomous system, and saving the calculated local autonomous system The result of the path calculation is performed, and the calculated entry node address in the path calculation result in the local autonomous system is sent to the PCE in the neighboring upstream autonomous system;

The PCE in the intermediate autonomous system calculates the path in the local autonomous system, and saves the calculated path calculation result in the local autonomous system and the ingress node address and PCE address of the adjacent downstream autonomous system, and is adjacent to its own upstream autonomy. Calculated by PCE transmission in the system The entry node address in the path calculation result in the local autonomous system;

The PCE in the autonomous system where the client device is located calculates the path in the local autonomous system, and sends the calculated path calculation result in the local autonomous system and the ingress node address and PCE address of the neighboring downstream autonomous system to the client device. .

The embodiment of the invention discloses a system for calculating a traffic engineering path, the system comprising: a client device, a PCE in an autonomous system where the client device is located, a PCE in the most downstream autonomous system where the destination node is located, and an inter-autonomous system PCE, where,

The PCE in the most downstream autonomous system is used to calculate the path in the local autonomous system, and saves the calculated path calculation result in the local autonomous system, and sends the calculated local autonomous system to the PCE in its neighboring upstream autonomous system. The entry node address in the path calculation result; the PCE in the intermediate autonomous system is used to calculate the path in the local autonomous system, and saves the calculated path calculation result in the local autonomous system and the PCE in the adjacent downstream autonomous system. The address and the ingress node address are sent to the PCE in the neighboring upstream autonomous system to calculate the ingress node address in the path calculation result in the local autonomous system;

The PCE in the autonomous system where the client device is located is used to calculate the path in the local autonomous system, and sends the calculated path calculation result in the local autonomous system and the PCE address in the adjacent downstream autonomous system to the client device. Ingress node address;

The client device is configured to receive information returned by the PCE in the autonomous system.

The embodiment of the invention discloses a path computing device PCE, which includes a main processing module and a storage module, wherein

The main processing module is used to:

When receiving the path calculation request message carrying the destination node address and the identification sequence number, determining whether the destination node is in the local autonomous system, and if so, calculating the path in the local autonomous system, and calculating the calculated internal The path calculation result and the identification sequence number are sent to the storage module, and the calculated internal Autonomous System is sent to the PCE in the adjacent upstream autonomous system. The path of the entry node and the identification sequence number in the path calculation result; otherwise, the path calculation request message is forwarded to the PCE in the adjacent downstream autonomous system;

When the ingress node address and the identification sequence number in the neighboring downstream system sent by the neighboring downstream PCE are received, the path in the local autonomous system is calculated, and it is determined whether the client device that initiates the path calculation request message is in the local autonomous system, if If yes, the calculated path calculation result in the local autonomous system and the PCE address and the ingress node address in the adjacent downstream autonomous system are returned to the client device; otherwise, the calculated path calculation result in the local autonomous system is calculated. The identification sequence number, the PCE address and the ingress node address in the adjacent downstream autonomous system are sent to the storage module, and the identification number and the calculated path calculation result in the local autonomous system are returned to the PCE in the adjacent upstream autonomous system. Ingress node address in ;

a storage module, configured to save information sent by the main processing module.

It can be seen from the foregoing technical solution that, in the calculation process of the traffic engineering path, the path computing device PCE saves the path calculation result in the local autonomous system and the path computing device address and the ingress node address in the adjacent downstream autonomous system in the calculation process of the traffic engineering path. Local, and only inform the neighboring upstream autonomous system of its own address and the ingress node address in the local autonomous system, so that the PCE address in an autonomous system is limited to be known by the adjacent upstream autonomous system, and does not spread to all upstream autonomous In the system. BRIEF DESCRIPTION OF THE DRAWINGS

1 is a schematic diagram of establishing a TE path between two autonomous systems in the prior art; FIG. 2 is a flowchart of a method for calculating a TE path according to an embodiment of the present invention;

3 is a flow chart of establishing a TE path according to the TE path calculated in FIG. 2 according to an embodiment of the present invention;

4 is a schematic diagram of a scenario for calculating a TE path and establishing a TE path according to an embodiment of the present invention; FIG. 5 is a structural block diagram of a system for calculating a traffic engineering path according to an embodiment of the present invention; Figure

FIG. 6 is a structural block diagram of a PCE according to an embodiment of the present invention. Mode for carrying out the invention

2 is a flow chart of a method for calculating a TE path according to an embodiment of the present invention. As shown in Figure 2, the following steps are included:

Step 201: The path calculation device PCE in the most downstream autonomous system where the destination node is located calculates the path in the local autonomous system, and saves the calculated path calculation result in the local autonomous system to the PCE in the neighboring upstream autonomous system. The calculated entry node address in the calculated path calculation result in the local autonomous system.

Step 202: The PCE in the intermediate autonomous system calculates a path in the local autonomous system, and saves the calculated path calculation result in the local autonomous system and the ingress node address and the PCE address of the neighboring downstream autonomous system to the self. The PCE in the neighboring upstream autonomous system transmits the calculated ingress node address in the path calculation result in the local autonomous system.

In this step, the intermediate autonomous system is an autonomous system that passes from the autonomous system where the client device is located to the autonomous system where the destination node is located.

Step 203: The PCE in the autonomous system where the PCC is located calculates a path in the local autonomous system, and sends the calculated path calculation result in the local autonomous system and the ingress node address and the PCE address of the neighboring downstream autonomous system to the PCC.

So far, the process of calculating the TE path is completed. In this process, the address information of the PCE is limited to be known by the adjacent upstream autonomous system, and is not spread to all upstream autonomous systems.

FIG. 3 is a flow chart of establishing a TE path according to the TE path calculated in FIG. 2 according to an embodiment of the present invention. As shown in Figure 3, the following steps are included:

Step 301: The PCC establishes a path in the local autonomous system according to the received path calculation result. The path sends the received PCE address to the ingress node indicated by the received ingress node address.

Step 302: The ingress node in the intermediate autonomous system obtains the path calculation result, the PCE address and the ingress node address in the adjacent downstream autonomous system from the PCE indicated by the received PCE address, and establishes the autonomy according to the obtained path calculation result. The path in the system sends the acquired PCE address to the ingress node indicated by the acquired ingress node address.

Step 303: The ingress node in the most downstream autonomous system acquires a path calculation result from the PCE indicated by the received PCE address, and establishes a path in the local autonomous system according to the obtained path calculation result.

This completes the TE path establishment process.

In order to make the technical solution of the present invention more clear, the present invention will be further described in detail below with reference to a specific example.

FIG. 4 is a schematic diagram of a scenario for calculating a TE path and establishing a TE path according to an embodiment of the present invention. As shown in Figure 4, the client device PCC located in the autonomous system AS 300 needs to establish a path to the node R5 in the autonomous system AS 500.

In the figure 4, the PCC first sends a path calculation request message to the PCE3 in the autonomous system AS 300. The path request message carries the address of the destination node R5 and the identification number X of the path calculation. The PCC initiates the path calculation request for a variety of reasons. For example, after receiving a packet and parsing it, it finds that there is no forwarding path for storing the destination address of the packet, or that a fixed channel needs to be established for a certain service, and PCC Before the path calculation request message is sent, a unique identifier sequence number is assigned to the calculation. In this embodiment, the identifier sequence number is X. After receiving the path calculation request message, PCE3 finds that R5 is located in AS 600, and must reach AS 500 through Autonomous System AS 400, and then forward the path calculation request message to PCE4 in AS 400, also in AS 400. The PCE 4 in turn forwards the path computation request message to the PCE 5 in the AS 500. PCE5 receives the path calculation request message After that, the TE path R4-R5 in the AS 500 is calculated, the identification number X and the calculated path R4-R5 are locally saved, and then the calculated entry in the TE path R4-R5 in the AS 500 is returned to the PCE4. The address of the node R4 and the identification number X. After receiving the address and the identification number X of the ingress node R4 sent by the PCE5, the PCE4 calculates the TE path R2-R3 in the AS 400, and locally stores the calculated identification number X, R4 address, the address of the PCE5, and the calculated The path R2-R3 then returns to PCE3 the calculated address and identification number X of the ingress node R2 in the TE path R2-R3 within the AS 400. After receiving the address of the ingress node R2 and the identification number X sent by the PCE4, the PCE3 determines that it and the client PCC are located in the same AS 300, and after calculating the TE path PCC-R1 in the AS 300, the calculation result is obtained. It is sent to the PCC along with the address of the ingress node R2 of the adjacent downstream autonomous system AS 400 and the address of PCE4. At this point, the TE path calculation from PCC to R5 is completed, and the PCC can initiate a path establishment message according to the calculation result.

In the above process shown in FIG. 4, the PCE discovery protocol is responsible for discovering the existence and computing power of the PCE and transmitting corresponding information to the PCC that initiates the path calculation request, and the PCC selects an appropriate PCE according to the information sent by the protocol and The transmission path is calculated, these are prior art and will not be described in detail here.

In FIG. 4, the TE path establishment process is: After receiving the path calculation result in the AS 300 returned by the PCE3 and the address of the ingress node R2 and the address of the PCE4 in the AS 400, the PCC initiates path establishment signaling by using a signaling protocol. The message, the ERO parameter of the message includes the path calculation result in the AS 300, the address of the ingress node R2 in the AS 400, the address of the PCE4, and the identification number X. The path establishment signaling message arrives at the ingress node R2 in the AS 400 indicated in the ERO after establishing a path in the AS 300 according to the path calculation result in its own ERO. R2 sends a query request message including the identification number X to the PCE 4 according to the address of the PCE 4 included in the path establishment signaling message. After receiving the inquiry request message, the PCE4 returns the path calculation result R2-R3 corresponding to the identification number X and the saved R4 to R2. Address and address of PCE5. R2 inserts the path calculation results R2-R3 and the address of R4 and the address of PCE5 returned by PCE4 into the ERO parameters of the path establishment signaling message. The path establishment signaling message arrives at the ingress node R4 in the AS 500 indicated in the ERO according to the path calculation result R2-R3 in the ERO after establishing the path in the AS 400. R4 sends a query request message including the identification number X to the PCE 5 according to the address of the PCE5 included in the path establishment signaling message. After receiving the inquiry request message, the PCE 5 returns the path calculation result R4-R5 corresponding to the identification number X to R4. R4 inserts the path calculation result R4-R5 returned by PCE5 into the ERO parameter of the path establishment signaling message. The path establishment signaling message establishes a path within the AS 500 based on the path calculation result R4-R5 in its own ERO. At this point, the establishment process of the TE path from PCC to R5 is completed.

FIG. 5 is a block diagram showing the structure of a system for calculating a traffic engineering path according to an embodiment of the present invention. As shown in Figure 5, the system includes: PCC, PCE in the autonomous system where the PCC is located, PCE in the most downstream autonomous system where the destination node is located, and PCE in the intermediate autonomous system. Here, the intermediate autonomous system refers to an autonomous system through which the path between the PCC and the destination node passes, except for the autonomous system in which the PCC is located in the autonomous system and the destination node. For example, the AS 400 in FIG. 4 is an intermediate autonomous system.

In FIG. 5, the PCC is configured to send a path calculation request message to the PCE in the autonomous system, where the destination node address and the identification number of the current path calculation are carried; and the message for receiving the return of the PCE in the autonomous system is received.

The PCE in the autonomous system in which the PCC is located is used to forward the path calculation request message to the PCE of the neighboring downstream autonomous system; and to receive the neighboring downstream of the PCE returned by the neighboring downstream autonomous system. After the ingress node address in the autonomous system, calculate the path in the local autonomous system, and return the path calculation result in the autonomous system to the PCC, the address of the PCE in its neighboring downstream autonomous system, and the neighboring downstream autonomous system. The address of the ingress node. The PCE in the intermediate autonomous system is configured to forward to the PCE of the neighboring downstream autonomous system after receiving the path calculation request message, and is used to receive the neighboring downstream autonomy of the PCE returned by the neighboring downstream autonomous system. After the ingress node address in the system, calculate the path in the local autonomous system, save the path calculation result in the autonomous system, the identification sequence number, the address of the PCE in its neighboring downstream autonomous system, and the entry in its neighboring downstream autonomous system. The address of the node returns the identification sequence number and the entry node address in the path calculation result in the local autonomous system to the PCE in the neighboring upstream autonomous system.

The PCE in the most downstream autonomous system is configured to calculate a path in the local autonomous system after receiving the path calculation request message sent by the PCE in the neighboring upstream autonomous system, and save the path calculation result in the local autonomous system and the The serial number is identified, and the identification number and the entry node address in the path calculation result in the local autonomous system are returned to the PCE in the neighboring upstream autonomous system.

In Fig. 5, the number of PCEs in the intermediate autonomous system can be arbitrary, and the case in Fig. 5 is given when there is only one PCE in the intermediate autonomous system.

The system shown in Figure 5 further includes: an ingress node in the intermediate autonomous system and an ingress node in the most downstream autonomous system for participating in the establishment of the TE path.

In FIG. 5, when establishing a TE path, the PCC is configured to establish a path in the local autonomous system according to the received path calculation result in the local autonomous system, and according to the received address of the ingress node in the adjacent downstream autonomous system. And sending the identification sequence number and the received address of the PCE in the neighboring downstream autonomous system to the ingress node in the neighboring downstream autonomous system.

The ingress node in the intermediate autonomous system is configured to obtain, according to the received PCE address and the identification sequence number, the path calculation result corresponding to the identification sequence number from the PCE in the local autonomous system, and the neighboring downstream autonomous system. The address of the PCE and the address of the ingress node in its neighboring downstream autonomous system, based on the obtained path calculation result. a path in the autonomous system, and sending the identification sequence number and the acquired address of the PCE in the neighboring downstream autonomous system to the neighboring downstream according to the obtained address of the ingress node in the neighboring downstream autonomous system. An ingress node in an autonomous system.

The ingress node in the most downstream autonomous system obtains the path calculation result corresponding to the identification sequence number from the PCE in the local autonomous system according to the received path, when the TE path is established, according to the received PCE address and the identification sequence number, according to the acquired path. The calculation results establish the path within the autonomous system.

FIG. 6 is a structural block diagram of a PCE according to an embodiment of the present invention. The PCE includes a main processing module 601, a storage module 602, and a query module 603 as shown in FIG.

In FIG. 6, the main processing module 601 is configured to: when receiving the path calculation request message carrying the destination node address and the identification sequence number, determine whether the destination node is in the local autonomous system, and if yes, calculate the path in the local autonomous system. And sending the path calculation result and the identification sequence number in the local autonomous system to the storage module 602, and sending the entry node address and the identification sequence number in the path calculation result in the local autonomous system to the PCE in the adjacent upstream autonomous system; otherwise, The path calculation request message is forwarded to the PCE in the adjacent downstream autonomous system.

The main processing module 601 is further configured to: when receiving the ingress node address and the identification sequence number in the path calculation result in the adjacent downstream autonomous system sent by the PCE in the adjacent downstream autonomous system, determine whether the PCC that initiates the path calculation request message is In the autonomous system, if yes, the path in the local autonomous system is calculated, and the path calculation result in the local autonomous system, the address of the PCE in the adjacent downstream autonomous system, and the neighboring downstream autonomous system are returned to the PCC. The address of the ingress node; otherwise, calculate the path in the local autonomous system, calculate the path result in the local autonomous system, the identification sequence number, the address of the PCE in the adjacent downstream autonomous system, and the address of the ingress node in the adjacent downstream autonomous system. The method is sent to the storage module 602, and returns the identification sequence number and the entry node address in the path calculation result in the local autonomous system to the PCE in the neighboring upstream autonomous system. The storage module 602 is configured to save information sent by the main processing module 601.

The querying module 603 is configured to query, from the storage module 602, information corresponding to the identification sequence number to the ingress node when receiving the query request that includes the identification sequence number sent by the ingress node in the autonomous system.

In summary, in the calculation process of the TE path, each PCE saves the path calculation result in the local autonomous system and the PCE address and the ingress node address in the adjacent downstream autonomous system locally. The technical solution of only informing the neighboring upstream autonomous system of its own address and the address of the ingress node in the autonomous system makes the address of the PCE in an autonomous system limited to be known by the adjacent upstream autonomous system, and does not spread to all. In the upstream autonomous system, the security of the PCE address is effectively improved.

The above is only the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modifications, equivalents, improvements, etc., which are made within the spirit and principles of the present invention, should be included. It is within the scope of the invention.

Claims

Claim

A method for calculating a traffic engineering path, the method comprising the steps of:

The path calculation device PCE in the most downstream autonomous system in which the destination node is located calculates the path in the local autonomous system, and saves the calculated path calculation result in the local autonomous system, and sends the calculated result to the PCE in its neighboring upstream autonomous system. The entry node address in the path calculation result in the local autonomous system;

The PCE in the intermediate autonomous system calculates the path in the local autonomous system, and saves the calculated path calculation result in the local autonomous system and the ingress node address and PCE address of the adjacent downstream autonomous system, and is adjacent to its own upstream autonomy. The PCE in the system sends the calculated entry node address in the path calculation result in the local autonomous system;

2. The method according to claim 1, wherein before the PCE in the most downstream autonomous system calculates a path in the local autonomous system, the method further comprises:

The client device sends a path calculation request message carrying the destination node address to the PCE in the autonomous system; the PCE in the autonomous system where the client device is located forwards the path calculation request message to the neighboring downstream autonomous system according to the address of the destination node. After receiving the path calculation request message sent by the PCE in the adjacent upstream autonomous system, the PCE in the intermediate autonomous system forwards the path calculation request message to the neighboring downstream autonomous system according to the address of the destination node. PCE, in this way, until the path computation request message arrives at the PCE in the most downstream autonomous system where the destination node is located.

3. The method of claim 1 or 2, wherein at the client device After the PCE in the autonomous system returns the path calculation result in the autonomous system and the ingress node address and PCE address of the neighboring downstream autonomous system to the client device, the PCE further includes:

The client device establishes a path in the local autonomous system according to the received path calculation result, and sends the received PCE address to the ingress node indicated by the received ingress node address; the ingress node in the intermediate autonomous system receives from the received node The PCE obtains the path calculation result and the PCE address and the ingress node address in the adjacent downstream autonomous system, and establishes the path in the local autonomous system according to the obtained path calculation result, and sends the acquired PCE address to the acquired The entry node indicated by the entry node address;

The ingress node in the most downstream autonomous system obtains the path calculation result from the PCE indicated by the received PCE address, and establishes the path in the local autonomous system according to the obtained path calculation result.

4. The method of claim 3, wherein

The path calculation request message further carries the identification number of the current path calculation; the PCE in the most downstream autonomous system where the destination node is located and the PCE in the intermediate autonomous system save the calculated path in the local autonomous system The calculation result is further saved with the ingress node address and the PCE address of the adjacent downstream autonomous system, and the identification sequence number is further saved; and the PCE in the neighboring upstream autonomous system is returned to the calculated path calculation result in the local autonomous system. At the same time, the ingress node address returns the identification sequence number;

The PCE in the autonomous system where the client device is located returns the calculated path calculation result in the local autonomous system and the ingress node address and PCE address of the neighboring downstream autonomous system to the client device, and returns the identifier. Serial number

The client device and the ingress node in the intermediate autonomous system send the received serial number while transmitting the received PCE address to the ingress node indicated by the received ingress node address; The ingress node obtains the path calculation result in the local autonomous system and the PCE address and the ingress node address in the adjacent downstream autonomous system, including:

The ingress node sends the query information carrying the identification sequence number to the PCE indicated by the received PCE address; the path calculation result corresponding to the identification sequence number saved by the PCE receiving the query information, and the PCE in the adjacent downstream autonomous system The address and the address of the ingress node are returned to the ingress node that sent the query information.

A system for calculating a traffic engineering path, the system comprising: a client device, a PCE in an autonomous system where the client device is located, a PCE in a most downstream autonomous system where the destination node is located, and an intermediate autonomous system PCE, where,

6. The system of claim 5 wherein:

The client device is further configured to send a path calculation request message carrying a destination node address to a PCE in the local autonomous system;

The PCE in the autonomous system where the client device is located is further configured to: after receiving the path calculation request message, forward the path calculation request to the neighbor according to the address of the destination node. PCE in the downstream autonomous system;

The PCE in the intermediate autonomous system is further configured to: after receiving the path calculation request message, forward the path calculation request to the PCE in the neighboring downstream autonomous system according to the address of the destination node;

The PCE in the most downstream autonomous system is configured to calculate the path in the local autonomous system after receiving the path calculation request message, save the path calculation result in the local autonomous system, and send the original to the PCE in the neighboring upstream autonomous system. The address of the entry section within the autonomous system.

The system of claim 5 or claim 6, wherein the system further comprises: an ingress node in the intermediate autonomous system and an ingress node in the most downstream autonomous system, wherein the client device is configured to The received path calculation result establishes a path in the local autonomous system, and sends the received address of the PCE to the ingress node indicated by the received ingress node address;

An ingress node in the intermediate autonomous system is configured to obtain a path calculation result and a PCE address and an ingress node address in the neighboring downstream autonomous system from the PCE indicated by the received PCE address, and establish an internal autonomous system according to the obtained path calculation result. Path, sending the acquired address of the PCE to the ingress node indicated by the acquired ingress node address;

The ingress node in the most downstream autonomous system is configured to obtain a path calculation result from the PCE indicated by the received PCE address, and establish a path in the local autonomous system according to the obtained path calculation result.

8. The system of claim 7 wherein:

The client device is further configured to carry the identifier number of the current path calculation in the path calculation request message sent to the PCE in the local autonomous system;

The PCE in the most downstream autonomous system in which the destination node is located and the PCE in the intermediate autonomous system are used to save the calculated path calculation result in the local autonomous system and the ingress node address and PCE address of the adjacent downstream autonomous system. At the same time, further used to save the target The serial number is used to return the calculated ingress node address in the path calculation result in the local autonomous system to the PCE in the neighboring upstream autonomous system, and is further used to return the identifier to the PCE in the neighboring upstream autonomous system. Serial number

The PCE in the autonomous system where the client device is located is used to return the calculated path calculation result in the local autonomous system and the ingress node address and the PCE address of the neighboring downstream autonomous system to the client device, and further use Returning the identification serial number to the client device;

The client device and the ingress node in the intermediate autonomous system are configured to send the PCE address in the received adjacent downstream autonomous system to the ingress node in the adjacent downstream autonomous system, and further The identification sequence number is sent to an ingress node in an adjacent downstream autonomous system;

The ingress node in the intermediate autonomous system and the ingress node in the most downstream autonomous system are configured to send, to the PCE indicated by the received PCE address, the query information carrying the identification sequence number; the PCE that receives the query information, The path calculation result corresponding to the identification sequence number saved by itself, the address of the PCE in the adjacent downstream autonomous system, and the address of the ingress node are returned to the ingress node that sends the query information.

A path computing device (PCE), wherein the PCE includes a main processing module and a storage module, where

The main processing module is used to:

When receiving the path calculation request message carrying the destination node address and the identification sequence number, determining whether the destination node is in the local autonomous system, and if so, calculating the path in the local autonomous system, and calculating the calculated internal The path calculation result and the identification sequence number are sent to the storage module, and the calculated entry node address and the identification sequence number in the path calculation result in the local autonomous system are sent to the PCE in the neighboring upstream autonomous system; otherwise, the path calculation request is performed. The message is forwarded to the PCE in the adjacent downstream autonomous system; When the ingress node address and the identification sequence number in the adjacent downstream autonomous system sent by the neighboring downstream PCE are received, the path in the local autonomous system is calculated, and the client device that initiates the path calculation request message is determined to be in the local autonomous system. If yes, the calculated path calculation result in the local autonomous system and the PCE address and the ingress node address in the adjacent downstream autonomous system are returned to the client device; otherwise, the calculated path calculation result in the local autonomous system is calculated. The identification sequence number, the PCE address and the ingress node address in the adjacent downstream autonomous system are sent to the storage module, and the identification number and the calculated path calculation result in the local autonomous system are returned to the PCE in the adjacent upstream autonomous system. Ingress node address in ;

The PCE according to claim 9, wherein the PCE further comprises a query module, configured to query from the storage module when receiving a query request including an identifier serial number sent by an ingress node in the autonomous system Information corresponding to the identification sequence number is returned to the ingress node.