CN101984597B - Computing method and system for multi-domain two-way label switched path - Google Patents

Computing method and system for multi-domain two-way label switched path Download PDF

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CN101984597B
CN101984597B CN201010531403.0A CN201010531403A CN101984597B CN 101984597 B CN101984597 B CN 101984597B CN 201010531403 A CN201010531403 A CN 201010531403A CN 101984597 B CN101984597 B CN 101984597B
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territory
domain
pce
vspt
link
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CN101984597A (en
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卢刚
汪学蓉
王大江
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ZTE Corp
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ZTE Corp
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/02—Topology update or discovery
    • H04L45/04—Interdomain routing, e.g. hierarchical routing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/48—Routing tree calculation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/50—Routing or path finding of packets in data switching networks using label swapping, e.g. multi-protocol label switch [MPLS]

Abstract

The invention discloses a computing method for a multi-domain two-way label switched path, which comprises the following steps: after a PCE of a domain in which a destination node is positioned receives a PCReq message, the PCE computes VSPT according to an intra-domain two-way LSP computed by the PCE and a one-way inter-domain link path, and sends the VSPT to a PCE of an upstream domain; and the PCE of the upstream domain computes new VSPT according to an intra-domain two-way LSP computed by the PCE, a one-way inter-domain link path and the VSPT, and sends the new VSPT to a PCE of an upstream domain until a PCE of a domain in which a source node is positioned sends the final VSPT to the source node. The invention also provides a computing system for the multi-domain two-way label switched path. The technical scheme of the invention realizes computation of an end-to-end multi-domain two-way LSP by BRPC.

Description

A kind of computational methods of multi-domain two-way label switched path and system
Technical field
The Generalized Multiprotocol Label that the present invention relates to the communications field exchanges (GMPLS, GeneralizedMultiprotocol Label Switching) agreement, particularly relates to a kind of computational methods and system of multi-domain two-way label switched path.
Background technology
In the multi-layer multi-domain network using GMPLS agreement, the multiple node with different exchange capacity and speed can be divided into not same area or different layers according to the actual requirements, these territories can be router domain, optical transfer network (OTN, Optical Transport Network) territory or Packet Transport Network (PTN, Packet TransportNetwork) territory etc.At employing autonomous system (AS, Autonomous System) carry out in the multiple-domain network divided, the backward recursive path computing of Based PC E (BRPC, Backward RecuisivePCE-Based Computation) can be adopted to carry out multi-domain path calculating.
Be described BRPC in RFC5441 agreement, this computational process depends on the communication between co-operating path-calculating element (PCE, Path Computation Element).Path computing client (PCC, Path Computation Client) to the PCE path computation request (PCReq in its territory, PathComputation Request) message, this message forwards between the PCE in each territory, until message arrives the PCE being responsible for calculating label switched path (LSP, Label Switch Path) territory, destination node place; PCE in object territory creates a virtual shortest path tree (VSPT be made up of the potential path arriving destination node, Virtual Shortest Path Tree), and at path computing response (PCRep, PathComputation Response) this VSPT is passed to previous PCE in message, then each PCE increases VSPT successively, and it is passed to passback, until the PCE in territory, source node place, this PCE uses VSPT to select a path end to end, and path is sent to PCC.
Wherein, BRPC has following agreement:
1, one group of territory (i) enter boundary node, be denoted as BN-en (k, i), wherein BN-en (k, i) is that the kth of territory i enters boundary node;
2, one group of territory (i) go out boundary node, be denoted as BN-ex (k, i), wherein BN-ex (k, i) is that the kth of territory i goes out boundary node;
3, Fig. 1 is the VSPT schematic diagram in prior art in BRPC computational process, as shown in Figure 1, the multiple spot being returned to PCE (i-1) by PCE (i) is denoted as VSPT (i) to the tree of a bit (MP2P, MultiPoint To Point).
In prior art, the process utilizing BRPC to calculate multi-domain path is specially:
Step 1, in AS (1) territory, PCReq message is sent to the PCE in this territory by source node PCC, then the order according to the territory in the territory sequence of specifying is transmitted along the PCE in multiple territory by PCReq message, until arrive the PCE in territory, destination node place, i.e. PCE (n).
Step 2, PCE (n) uses suitable path computation algorithm (as CSPF) to calculate VSPT (n), and the VSPT (n) calculated is returned to PCE (n-1); Wherein, VSPT (n) by row from territory (n) each enter boundary node BN-en (j, n) to destination node the shortest constrained path form.
Step 3, as shown in Figure 1, equal n-1 to i for i and equal 2, PCE (i) and calculate VSPT (i), this VSPT (i) is made up of the shortest constrained path between each BN-en (j, i) and destination node.PCE (i) utilizes self traffic engineering storehouse (TED, Traffic Engineering Database) and VSPT (i+1) calculate, also need, by the multiple domain link in territory AS (i), to join in territory AS (i+1) and calculate together.
Step 4: the PCE (1) in last territory, PCC place calculates the shortest end-to-end constrained path from PCC to destination node, and utilizes PCRep message to return to PCC in corresponding path, i.e. source node.
Said process is the general process of the calculating of the multi-domain path of BRPC algorithm, the algorithm provides a kind of method solved by the unidirectional LSP of many PCE Collaboration computing under multiple domain scene.But, when using BRPC algorithm to carry out the calculating of multiple domain bidirectional LSP, calculate together if the Inter-AS link of link field AS (i) is also joined in territory AS (i+1), PCE also needs the attribute information of the two-way link knowing multiple domain link, how to obtain these attribute informations about PCE, in RFC5441, do not provide relevant implementation.Fig. 2 is the schematic diagram of the acquisition of information of multiple domain link in prior art, as shown in Figure 2, although RFC5316 and RFC5392 is respectively based on the routing protocol (ISIS of Intermediate System-to-Intermediate System, IntermediateSystem to Intermediate System Routing Protocol) and ospf (OSPF, Open Shortest Path First) type-length-value (TLV of protocol definition expansion, Type LengthValue), comprise local ip address, local port identifies, far-end IP address, remote port identifies, far-end AS ID, link bandwidth, weight, sharing memory (SRLG, Shared Risk Link Groups) etc., but after these information spread in whole territory AS (i), PCE (i) also can only know all links in the AS of territory and A1 → B1, the unidirectional domain-to-domain link of A2 → B2.For two-way end-to-end LSP, the attribute information of reverse domain-to-domain link (A1 ← B1 and A2 ← B2) still has no idea to be advertised to PCE (i), thus causes calculating multiple domain bidirectional LSP.
Summary of the invention
In view of this, main purpose of the present invention is the computational methods and the system that provide a kind of multi-domain two-way label switched path, realizes utilizing BRPC to calculate multiple domain bidirectional LSP end to end.
For achieving the above object, technical scheme of the present invention is achieved in that
The invention provides a kind of computational methods of multi-domain two-way label switched path, comprising:
After the path-calculating element (PCE) in territory, destination node place receives path computing request (PCReq) message, in the territory calculated according to self, between bidirectional label exchange path (LSP) and unidirectional domain, link paths calculates virtual shortest path tree (VSPT), and described VSPT is sent to the PCE in territory, upstream;
Link paths and described VSPT between bidirectional LSP, unidirectional domain in the territory that the PCE in territory, upstream calculates according to self, calculate new VSPT and send to the PCE in self territory, upstream, until final VSPT is sent to source node by the PCE in territory, source node place.
In said method, in the described territory calculated according to self, between bidirectional LSP and unidirectional domain, link paths calculating VSPT is:
PCE calculate this territory all enter bidirectional LSP in boundary node to the territory of destination node, PCE calculate territory, upstream to this territory unidirectional domain between link paths, by territory between bidirectional LSP and unidirectional domain link paths splice, obtain VSPT.
In said method, link paths and described VSPT between bidirectional LSP, unidirectional domain in the territory that the PCE in territory, described upstream calculates according to self, calculating new VSPT is:
PCE calculate this territory all enter boundary node to this territory all go out boundary node territory in bidirectional LSP, PCE calculate territory, upstream to this territory unidirectional domain between link paths; By in territory between bidirectional LSP and unidirectional domain link paths splice, and then splice downstream domain PCE send VSPT, obtain new VSPT.
In said method, the method comprises further:
The PCE in intermediate field or first territory to this territory to downstream domain autonomous system (AS) unidirectional domain between link paths carry out authenticate reverse, if be proved to be successful, then execution route is not deleted, if authentication failed, then link paths between this unidirectional domain in described VSPT is deleted, the VSPT after having verified is sent to the PCE in territory, upstream.
The computational methods of the present invention's also a kind of multi-domain two-way label switched path, comprising:
After the PCE in territory, destination node place receives PCReq message, calculate the multiple domain bidirectional LSP of self, obtain VSPT, described VSPT is sent to the PCE in territory, upstream;
The PCE in territory, upstream calculates new VSPT according to the multiple domain bidirectional LSP of the VSPT received and self calculating, and sends to the PCE in self territory, upstream, until final VSPT is sent to source node by the PCE in territory, source node place.
In said method, the multiple domain bidirectional LSP of described calculating self is:
PCE calculate in territory, upstream all go out boundary node in this territory all go out the multiple domain bidirectional LSP of boundary node.
In said method, the method also comprises:
PCE carries out examination process to the multiple domain bidirectional LSP calculated.
In said method, described PCE carries out examination to the multiple domain bidirectional LSP calculated and is treated to:
Check whether link circuit resource, the territory, upstream of the two-way link in territory meet the demands to the link circuit resource of the unidirectional domain-to-domain link in this territory, are deleted by the link do not met the demands from the multiple domain bidirectional LSP calculated;
Or, check the link circuit resource of the two-way link in territory, whether territory, upstream meet the demands to the link circuit resource of the unidirectional domain-to-domain link in this territory to the link circuit resource of the unidirectional domain-to-domain link in this territory, downstream domain, the link do not met the demands is deleted from the multiple domain bidirectional LSP calculated;
Or, check the two-way resource of two-way link in this territory, check whether downstream domain meets the demands to the link circuit resource of the unidirectional domain-to-domain link in this territory, is deleted by the link do not met the demands from the multiple domain bidirectional LSP calculated.
In said method, the PCE in territory, described upstream calculates new VSPT according to the VSPT received with the multiple domain bidirectional LSP self calculated and is:
The VSPT that the PCE of the multiple domain bidirectional LSP after examination and downstream domain sends splices by PCE, generates new VSPT.
The invention provides a kind of computing system of multi-domain two-way label switched path, comprising: the PCE in the PCE in territory, destination node place, the PCE in territory, upstream, territory, source node place; Wherein,
The PCE in territory, destination node place, after receiving PCReq message, in the territory calculated according to self, between bidirectional LSP and unidirectional domain, link paths calculates VSPT, and described VSPT is sent to the PCE in territory, upstream;
The PCE in territory, upstream, for link paths and described VSPT between bidirectional LSP, unidirectional domain in the territory that calculates according to self, calculates new VSPT and sends to the PCE in self territory, upstream;
The PCE in territory, source node place, for sending to source node by final VSPT.
The invention provides a kind of computing system of multi-domain two-way label switched path, comprising: the PCE in the PCE in territory, destination node place, the PCE in territory, upstream, territory, source node place; Wherein,
The PCE in territory, destination node place, after receiving PCReq message, calculates the multiple domain bidirectional LSP of self, obtains VSPT, described VSPT is sent to the PCE in territory, upstream;
The PCE in territory, upstream, for calculating new VSPT according to the multiple domain bidirectional LSP of the VSPT received and self calculating, and sends to the PCE in self territory, upstream;
The PCE in territory, source node place, for sending to source node by final VSPT.
The computational methods of multi-domain two-way label switched path provided by the invention and system, after the PCE in territory, destination node place receives PCReq message, in the territory calculated according to self, between bidirectional LSP and unidirectional domain, link paths calculates VSPT, and described VSPT is sent to the PCE in territory, upstream; Link paths and described VSPT between bidirectional LSP, unidirectional domain in the territory that the PCE in territory, upstream calculates according to self, calculate new VSPT and send to the PCE in self territory, upstream, until final VSPT is sent to source node by the PCE in territory, source node place; Or, after the PCE in territory, destination node place receives PCReq message, calculate the multiple domain bidirectional LSP of self, obtain VSPT, described VSPT is sent to the PCE in territory, upstream; The PCE in territory, upstream calculates new VSPT according to the multiple domain bidirectional LSP of the VSPT received and self calculating, and send to the PCE in self territory, upstream, until final VSPT is sent to source node by the PCE in territory, source node place, method BRPC of the prior art being calculated to unidirectional multiple domain LSP is expanded, on the basis of attribute information not utilizing link between bi-directional domain, simply achieve the calculating of multiple domain bidirectional LSP end to end.
Accompanying drawing explanation
Fig. 1 is the VSPT schematic diagram in prior art in BRPC computational process;
Fig. 2 is the schematic diagram of the acquisition of information of multiple domain link in prior art;
Fig. 3 is the principle signal picture group that the present invention realizes the computational methods of multi-domain two-way label switched path;
Fig. 4 is the schematic flow sheet that the present invention realizes the computational methods of multi-domain two-way label switched path;
Fig. 5 is that in Fig. 4, step 402 and 403 utilizes connecting method to calculate the schematic flow sheet of the method for VSPT;
Fig. 6 is the schematic flow sheet that in Fig. 4, step 402 and 403 utilizes the method for an account form calculating VSPT;
Fig. 7 is the principle schematic that the present invention realizes the embodiment one of the computational methods of multi-domain two-way label switched path;
Fig. 8 is the schematic flow sheet that the present invention realizes the embodiment one of the computational methods of multi-domain two-way label switched path;
Fig. 9 is the principle schematic that the present invention realizes the embodiment two of the computational methods of multi-domain two-way label switched path;
Figure 10 is the schematic flow sheet that the present invention realizes the embodiment two of the computational methods of multi-domain two-way label switched path;
Figure 11 is the structural representation that the present invention realizes the computing system of multi-domain two-way label switched path.
Embodiment
Basic thought of the present invention is: after the PCE in territory, destination node place receives PCReq message, and in the territory calculated according to self, between bidirectional LSP and unidirectional domain, link paths calculates VSPT, and described VSPT is sent to the PCE in territory, upstream; Link paths and described VSPT between bidirectional LSP, unidirectional domain in the territory that the PCE in territory, upstream calculates according to self, calculate new VSPT and send to the PCE in self territory, upstream, until final VSPT is sent to source node by the PCE in territory, source node place; Or, after the PCE in territory, destination node place receives PCReq message, calculate the multiple domain bidirectional LSP of self, obtain VSPT, described VSPT is sent to the PCE in territory, upstream; The PCE in territory, upstream calculates new VSPT according to the multiple domain bidirectional LSP of the VSPT received and self calculating, and sends to the PCE in self territory, upstream, until final VSPT is sent to source node by the PCE in territory, source node place.
Below by drawings and the specific embodiments, the present invention is described in further detail again.
In the present invention, the territory going to source node direction in the computational process of agreement BRPC algorithm is territory, upstream, and the territory going to destination node direction is downstream domain.Fig. 3 is the principle signal picture group that the present invention realizes the computational methods of multi-domain two-way label switched path, for Fig. 3, as shown in Fig. 3 (a), having five territories in the computational process of BRPC algorithm, is AS (1), AS (i-1), AS (i), AS (i+1), AS (n) respectively; Wherein, territory headed by AS (i), AS (i-1), AS (i), AS (i+1) are intermediate field, and AS (n) is tail territory; In intermediate field, AS (i-1) is territory, upstream, AS (i) is this territory, AS (i+1) is downstream domain, and its PCE is respectively PCE (1), PCE (i-1), PCE (i), PCE (i+1), PCE (n).BRPC algorithm calculates the multiple domain bidirectional LSP from the source node AS (1) to the destination node in AS (n).
The present invention does following agreement: the kth that BN-ex (k, i) is AS (i) territory goes out boundary node; The kth that BN-en (k, i) is AS (i) territory enters boundary node; BN-ex (k, i-1) → BN-en (k, i) for go out from the kth in AS (i-1) territory boundary node to the kth in AS (i) territory individual enter boundary node BN-en (k, i) unidirectional domain-to-domain link, information BN-en (k in AS (i) territory of this unidirectional domain-to-domain link, i) node configures and carry out inundation in AS (i), the reverse link of this unidirectional domain-to-domain link is expressed as BN-ex (k, i-1) ← BN-en (k, i).BN-ex (k, i) ← BN-en (k, i+1) for enter from the kth in AS (i+1) territory boundary node to the kth in AS (i) territory individual go out boundary node BN-ex (k, i) unidirectional domain-to-domain link, information BN-ex (k in AS (i) territory of this unidirectional domain-to-domain link, i) node configures and carry out inundation in AS (i), the reverse link of this unidirectional domain-to-domain link is expressed as BN-ex (k, i) → BN-en (k, i+1).Wherein, for different territories, k value can be different.
The invention provides a kind of computational methods of multi-domain two-way label switched path, Fig. 4 is the schematic flow sheet that the present invention realizes the computational methods of multi-domain two-way label switched path, and as shown in Figure 4, the method comprises the following steps:
Step 401, PCReq message is sent to the PCE in this territory by PCC, and this PCReq message is transmitted to the PCE of downstream domain by the PCE in this territory, until this PCReq message arrives the PCE in territory, destination node place;
Concrete, source node PCC is according to this locality configuration or this territory PCE, and PCE in this territory of its PCReq of acquisition service, sends to this PCE by PCReq message, such as, PCE (1) in Fig. 3; This PCE determines that this territory is not territory, destination node place, then according to the automatic discovery information of PCE between configuration or territory, select the PCE of downstream domain, and PCReq message is forwarded to the PCE of downstream domain; The PCE of downstream domain determines that this territory is not territory, destination node place, then continue select the PCE of downstream domain and forward PCReq message to the PCE of this downstream domain, until PCReq message arrives the PCE in territory, destination node place, and such as, PCE (n) in Fig. 3.
Step 402, after the PCE in territory, destination node place receives PCReq message, in the territory calculated according to self, between bidirectional LSP and unidirectional domain, link paths calculates VSPT, or calculates the multiple domain bidirectional LSP of self, obtains VSPT; The VSPT calculated is sent to the PCE in territory, upstream by the PCE in territory, destination node place; Wherein, the multiple domain bidirectional LSP of self that the PCE in territory, destination node place (i.e. tail territory) calculates is VSPT;
Step 403, link paths and the VSPT that receives between bidirectional LSP, unidirectional domain in the territory that the PCE in territory, upstream calculates according to self, calculate new VSPT, or calculate new VSPT according to the VSPT received and the multiple domain bidirectional LSP that self calculates; The new VSPT calculated is sent to the PCE in self territory, upstream by the PCE in territory, upstream, until final VSPT is sent to source node by the PCE in territory, PCC place, this VSPT is the multiple domain bidirectional LSP of source node to destination node.
In the present invention, the specific implementation calculating the method for VSPT in step 402 and 403 comprises two kinds: connecting method and an account form.
Fig. 5 is that in Fig. 4, step 402 and 403 utilizes connecting method to calculate the schematic flow sheet of the method for VSPT, and as shown in Figure 5, the method comprises:
Step 501, bidirectional LSP in PCE (i) computational fields;
Concrete, if i=n, namely this territory AS (i) is tail territory, then PCE (i) calculate this territory AS (i) all enter bidirectional LSP in boundary node to the territory of destination node, wherein, the boundary node that enters in this territory AS (i) can BN-en (k, i) in reference diagram 3 (b);
If 1 < i < n, namely this territory AS (i) is intermediate field, then PCE (i) calculate this territory AS (i) all enter boundary node to this territory AS (i) all go out boundary node territory in bidirectional LSP; Wherein, this territory AS (i) all enter boundary node can BN-en (k in reference diagram 3 (b), i), the boundary node that goes out in this territory AS (i) can BN-ex (k, i) in reference diagram 3 (b);
If i=1, i.e. territory headed by this territory AS (i), then PCE (i) source node that calculates this territory AS (i) to all go out boundary node territory in bidirectional LSP, wherein, going out boundary node can BN-ex (k, i) in reference diagram 3 (b);
After above-mentioned calculating completes, bidirectional LSP in the territory calculated is kept at local internal system by PCE (i); In PCE computational fields, bidirectional LSP computational methods belong to prior art, repeat no more herein.
Step 502, PCE (i) calculates link paths between unidirectional domain;
Concrete, if 1 < i≤n, namely this territory AS (i) is tail territory or intermediate field, then PCE (i) territory, upstream AS (i-1) that calculates self to this territory AS (i) unidirectional domain between link paths, unidirectional domain-to-domain link can BN-ex (k in reference diagram 3 (b), i-1) → BN-en (k, i); Wherein, computational methods, with general path computing, belong to prior art, repeat no more herein;
If i=1, namely territory headed by this territory AS (i), does not deal with herein.
Step 503, PCE (i) according in territory between bidirectional LSP and unidirectional domain link paths calculate VSPT (i);
Concrete, if i=n, namely this territory AS (i) is tail territory, directly by territory between bidirectional LSP and unidirectional domain link paths splice, obtain VSPT (i); Such as, path 1 → 2 and path 2 → 3 are spliced, after splicing, obtains path 1 → 2 → 3;
If 1≤i < is n, namely this territory AS (i) is intermediate field or first territory, then first direct by territory between bidirectional LSP and unidirectional domain link paths splice, and then the PCE (i+1) splicing downstream domain AS (i+1) sends to the VSPT (i+1) of PCE (i) by PCRep message, obtain VSPT (i).
Step 504, PCE (i) carries out the verification process in reverse domain-to-domain link path;
Concrete, if i=n, namely this territory AS (i) is tail territory, does not do verification process herein;
If 1≤i < is n, namely this territory AS (i) is intermediate field or first territory, then PCE (i) to this territory AS (i) to downstream domain AS (i+1) unidirectional domain between link paths carry out authenticate reverse, unidirectional domain-to-domain link can BN-ex (k in reference diagram 3 (c), i) ← BN-en (k, i+1); If the bandwidth of link paths meets bandwidth constraint condition between unidirectional domain, namely between this unidirectional domain, the available bandwidth of link paths is greater than the required bandwidth of multiple domain bidirectional LSP, be then proved to be successful, on the contrary then authentication failed; If be proved to be successful, then execution route is not deleted, if authentication failed, is then deleted by link paths between this unidirectional domain in the VSPT (i) obtained in step 503; Finally, the VSPT (i) after having verified is sent to PCE (i-1) by PCRep message.
Fig. 6 is the schematic flow sheet that in Fig. 4, step 402 and 403 utilizes the method for an account form calculating VSPT, and as shown in Figure 6, the method comprises:
Step 601, PCE (i) calculates multiple domain bidirectional LSP;
Concrete, if 1 < i≤n, namely this territory AS (i) is tail territory or intermediate field, then PCE (i) calculate in territory, upstream AS (i-1) all go out boundary node in this territory AS (i) all go out the multiple domain bidirectional LSP of boundary node, wherein, the boundary node that goes out in territory, upstream AS (i-1) can BN-ex (k in reference diagram 3 (b), i-1), the boundary node that goes out in this territory AS (i) can BN-ex (k, i) in reference diagram 3 (b);
If i=1, i.e. territory headed by this territory AS (i), the source node (i.e. PCC) that then PCE (i) calculates this territory AS (i) goes out the multiple domain bidirectional LSP of boundary node to this territory AS (i), wherein going out boundary node can BN-ex (k, i) in reference diagram 3 (b);
The computational methods that PCE calculates multiple domain bidirectional LSP belong to prior art, repeat no more herein.
Step 602, PCE (i) carries out examination process to the multiple domain bidirectional LSP calculated;
Concrete, if i=n, namely this territory AS (i) is tail territory, first, for the link in this territory AS (i), checks whether the link circuit resource of the two-way link in this territory meets the demands; If the available link resource of the two-way link in territory is greater than this link circuit resource needed for multiple domain bidirectional LSP, then meets the demands, otherwise do not meet the demands; Then, for the domain-to-domain link part of this territory to territory, upstream, check whether territory, upstream AS (i-1) meets the demands to the link circuit resource of the unidirectional domain-to-domain link in this territory AS (i), this unidirectional domain-to-domain link can BN-ex (k in reference diagram 3 (b), i-1) → BN-en (k, i); If the available link resource of this unidirectional domain-to-domain link is greater than the link circuit resource needed for multiple domain bidirectional LSP, then meet the demands, otherwise do not meet the demands; If above-mentioned requirements is all satisfied, then execution route is not deleted, and does not meet the demands, delete in the multiple domain bidirectional LSP that the link this do not met the demands calculates from step 601 if there is at least one;
If 1 < i < n, namely this territory AS (i) is intermediate field, first, for the link in this territory AS (i), checks whether the link circuit resource of the two-way link in this territory meets the demands; Secondly, for the domain-to-domain link part of this territory to territory, upstream, check whether territory, upstream AS (i-1) meets the demands to the link circuit resource of the unidirectional domain-to-domain link in this territory AS (i), this unidirectional domain-to-domain link can BN-ex (k in reference diagram 3 (b), i-1) → BN-en (k, i); Then, to the domain-to-domain link part of this territory to downstream domain, check whether downstream domain AS (i+1) meets the demands to the link circuit resource of the unidirectional domain-to-domain link in this territory AS (i), wherein this unidirectional domain-to-domain link can BN-ex (k in reference diagram 3 (c), i) ← BN-en (k, i+1); If above-mentioned requirements is all satisfied, then execution route is not deleted, and does not meet the demands, delete in the multiple domain bidirectional LSP that the link this do not met the demands calculates from step 601 if there is at least one;
If i=1, i.e. territory headed by this territory AS (i), first, for the link in this territory AS (i), checks in this territory, whether the two-way resource of two-way link meets the demands; Then, for the domain-to-domain link part of this territory to downstream domain, check whether downstream domain AS (i+1) meets the demands to the link circuit resource of the unidirectional domain-to-domain link in this territory AS (i), wherein, this unidirectional domain-to-domain link can BN-ex (k in reference diagram 3 (c), i) ← BN-en (k, i+1); If above-mentioned requirements is all satisfied, then execution route is not deleted, and does not meet the demands, delete in the multiple domain bidirectional LSP that the link this do not met the demands calculates from step 601 if there is at least one.
Step 603, PCE (i) calculates VSPT (i) according to multiple domain bidirectional LSP;
Concrete, if i=n, namely territory AS (i) is tail territory, then namely the path in step 602 after examination is new VSPT (i), and this VSPT (i) is sent to PCE (i-1) by PCRep message;
If 1≤i < is n, namely this territory AS (i) is intermediate field or first territory, the VSPT (i+1) then needing the PCE (i+1) of the multiple domain bidirectional LSP after by examination in step 602 and downstream domain AS (i+1) to send splices, generate new VSPT (i), the new VSPT (i) obtained is sent to PCE (i-1) by PCRep message.
Embodiment one
Fig. 7 is the principle schematic that the present invention realizes the embodiment one of the computational methods of multi-domain two-way label switched path, and this embodiment calculates the method for VSPT for utilizing connecting method, as shown in Figure 7, there are three AS,, there are three PCE, i.e. PCE1, PCE2, PCE3 in i.e. AS1, AS2, AS3; R2 and R3 is the AS border router (ASBR, AS Border Router) of AS1, the ASBR of R4, R5, R6 and R7 to be the ASBR of AS2, R8 and R9 be AS3; Set up the multiple domain bidirectional LSP from R1 to R10, wherein, territory sequence is AS1 → AS2 → AS3, PCE sequence is PCE1 → PCE2 → PCE3.
Fig. 8 is the schematic flow sheet that the present invention realizes the embodiment one of the computational methods of multi-domain two-way label switched path, and as shown in Figure 8, the method comprises:
Step 801, the PCC of R1 sends PCReq message to PCE1;
Concrete, the PCC of R1 sends PCReq message to PCE1, comprises required parameter (RP, Request Parameters) object, END-POINTS object, territory sequence in this PCReq message all the time; In the present embodiment, the B value in RP object is 1, namely represents that domain-to-domain link is two-way link, END-POINTS object is that { R1, R10}, namely represent source node and the destination node of this two-way link, territory sequence be AS1-AS2-AS3}, and namely represent in two-way link need through territory.
Step 802, PCReq message is sent to PCE3 by PCE2 by PCE1;
Concrete, according to territory sequence, PCE1 determines that the downstream domain in self territory, place is AS2, then PCReq message is forwarded to the PCE2 of this downstream domain AS2, and this PCReq message is transmitted to PCE3 by PCE2.
Step 803, PCE3 calculates VSPT3, and the VSPT3 calculated is sent to PCE2;
Concrete, after PCE3 receives PCReq request, according to the territory sequence that it carries, determine Shi Wei territory, this territory, then calculate this territory AS3 enter boundary node (i.e. R8 and R9) to R10 territory between bidirectional LSP, between the territory then this calculated bidirectional LSP and the R6 → R8 precomputed and R7 → R9 unidirectional domain between link paths splice, obtain VSPT3; The VSPT3 calculated is sent to PCE2 by PCRep message by PCE3, and wherein, this VSPT3 is path sequence, i.e. (ERO1:R6-R8-R10, an ER02:R7-R8-R10).
Step 804, PCE2 calculates VSPT2 according to VSPT3, and the VSPT2 calculated is sent to PCE1;
Concrete, the territory sequence of carrying in the PCReq message that PCE2 sends according to previous PCE1, determine that this territory is intermediate field, what then calculate this territory AS2 enters bidirectional LSP between boundary node (i.e. R4 and R5) to the territory going out boundary node (i.e. R6 and R7), between the territory then this calculated bidirectional LSP and the R2 → R4 precomputed and R3 → R5 unidirectional domain between link paths splice, the VSPT3 that spliced path and PCE3 send combines by PCE2, obtains VSPT2; The VSPT2 calculated is sent to PCE1 by PCRep message by PCE2, and wherein, this VSPT2 is a path sequence, i.e. (ERO:R2-R4-R6-R8-R10).
Step 805, PCE1 calculates VSPT1 according to VSPT2, and the VSPT1 calculated is sent to R1;
Concrete, PCE1 calculates the unidirectional LSP of the boundary node (i.e. R2 and R3) of R1 to territory AS1, and the VSPT2 that unidirectional LSP and the PCE2 calculated sends is spliced, finally obtain VSPT1, this VSPT1 is a path sequence, i.e. (ERO:R1-R2-R4-R6-R8-R10); The VSPT1 calculated is sent to R1 by PCRep message by PCE1, and the so far calculating of the multiple domain bidirectional LSP of R1 to R10 completes.
Embodiment two
Fig. 9 is the principle schematic that the present invention realizes the embodiment two of the computational methods of multi-domain two-way label switched path, this embodiment is for the method utilizing an account form calculating VSPT, as shown in Figure 9, there are three AS, i.e. AS1, AS2, AS3, there are three PCE, i.e. PCE1, PCE2, PCE3; R2 and R3 is the ASBR of AS1, the ASBR of R4, R5, R6 and R7 to be the ASBR of AS2, R8 and R9 be AS3; Set up the multiple domain bidirectional LSP from R1 to R10, territory sequence is AS 1 → AS2 → AS3, PCE sequence is PCE1 → PCE2 → PCE3.
Figure 10 is the schematic flow sheet that the present invention realizes the embodiment two of the computational methods of multi-domain two-way label switched path, and as shown in Figure 10, the method comprises:
Step 1001, the PCC of R1 sends PCReq message to PCE1;
Concrete, the PCC of R1 sends PCReq message to PCE1, comprises RP object, END-POINTS object, territory sequence in this PCReq message all the time; In the present embodiment, in RP object, B value is 1, namely represents that domain-to-domain link is two-way link, END-POINTS object is that { R1, R10}, namely represent source node and the destination node of this two-way link, territory sequence be AS1-AS2-AS3}, and namely represent in two-way link need through territory.
Step 1002, PCReq message is sent to PCE3 by PCE2 by PCE1;
Concrete, according to territory sequence, PCE1 determines that the downstream domain in self territory, place is AS2, PCReq message is forwarded to the PCE2 of downstream domain AS2, and this PCReq message is transmitted to PCE3 by PCE2.
Step 1003, PCE3 calculates VSPT3, and the VSPT3 calculated is sent to PCE2;
Concrete, after PCE3 receives PCReq request, according to the territory sequence that it carries, determine Shi Wei territory, this territory, then computational fields AS2 go out the multiple domain bidirectional LSP of boundary node (i.e. R6 and R7) to destination node R10, obtain VSPT3, the VSPT3 calculated is sent to PCE2 by PCRep message by PCE3, and wherein, this VSPT3 is a path sequence, i.e. (ERO1:R6-R8-R10, ERO2:R7-R8-R10).
Step 1004, PCE2 carries out examination process to two-way domain-to-domain link;
Concrete, after PCE2 receives the PCRep message of PCE3 transmission, carry out examination process to the two-way domain-to-domain link of R6 ← R8 and R7 ← R9, concrete examination processing method can refer step 602.
Step 1005, PCE2 calculates VSPT2 according to VSPT3, and the VSPT2 calculated is sent to PCE1;
Concrete, the territory sequence of carrying in the PCReq message that PCE2 sends according to previous PCE1, determine that this territory is intermediate field, then computational fields AS1 go out the multiple domain bidirectional LSP that go out boundary node (i.e. R6 and R7) of boundary node (i.e. R2 and R3) to this territory AS2; The VSPT3 that the multiple domain bidirectional LSP calculated and PCE3 send combines by PCE2, obtain VSPT2, the VSPT2 calculated is sent to PCE1 by PCRep message by PCE2, wherein, this VSPT2 is a path sequence, i.e. (ERO:R2-R4-R6-R8-R10).
Step 1006, PCE1 carries out examination process to two-way domain-to-domain link;
Concrete, after PCE1 receives PCRep request, carry out examination process to the two-way domain-to-domain link of R2 ← R4 and R3 ← R5, concrete examination processing method can refer step 602.
Step 1007, PCE1 calculates VSPT1 according to VSPT2, and the VSPT1 calculated is sent to R1;
Concrete, PCE1 calculates the multiple domain bidirectional LSP that R1 to territory AS1 goes out boundary node (i.e. R2 and R3), and the VSPT2 that two-way for the multiple domain calculated LPS and PCE2 sends is spliced, finally obtain VSPT1, this VSPT1 is a path sequence, i.e. (ERO:R1-R2-R4-R6-R8-R10); The VSPT1 calculated is sent to R1 by PCRep message by PCE1, and the so far calculating of the multiple domain bidirectional LSP of R1 to R10 completes.
For realizing said method, the present invention also provides a kind of computing system of multi-domain two-way label switched path, Figure 11 is the structural representation that the present invention realizes the computing system of multi-domain two-way label switched path, as shown in figure 11, this system comprises: the PCE113 in the PCE111 in territory, destination node place, the PCE112 in territory, upstream, territory, source node place; Wherein,
The PCE111 in territory, destination node place, after receiving PCReq message, in the territory calculated according to self, between bidirectional LSP and unidirectional domain, link paths calculates VSPT, and described VSPT is sent to the PCE112 in territory, upstream;
The PCE112 in territory, upstream, for link paths and described VSPT between bidirectional LSP, unidirectional domain in the territory that calculates according to self, calculates new VSPT and sends to the PCE in self territory, upstream;
The PCE113 in territory, source node place, for sending to source node by final VSPT.
The present invention also provides a kind of computing system of multi-domain two-way label switched path, and as shown in figure 11, this system comprises: the PCE113 in the PCE111 in territory, destination node place, the PCE112 in territory, upstream, territory, source node place; Wherein,
The PCE111 in territory, destination node place, after receiving PCReq message, calculates the multiple domain bidirectional LSP of self, obtains VSPT, described VSPT is sent to the PCE112 in territory, upstream;
The PCE112 in territory, upstream, for calculating new VSPT according to the multiple domain bidirectional LSP of the VSPT received and self calculating, and sends to the PCE in self territory, upstream;
The PCE113 in territory, source node place, for sending to source node by final VSPT.
In above-mentioned two systems, the PCE in the PCE in destination node, territory, destination node place, source node and territory, source node place is one, and the PCE in territory, upstream and territory, upstream is one or more.
The above, be only preferred embodiment of the present invention, be not intended to limit protection scope of the present invention, and all any amendments done within the spirit and principles in the present invention, equivalent replacement and improvement etc., all should be included within protection scope of the present invention.

Claims (9)

1. computational methods for multi-domain two-way label switched path, is characterized in that, the method comprises:
After the path-calculating element (PCE) in territory, destination node place receives path computing request (PCReq) message, in the territory calculated according to self, between bidirectional label exchange path (LSP) and unidirectional domain, link paths calculates virtual shortest path tree (VSPT), and described VSPT is sent to the PCE in territory, upstream;
Link paths and described VSPT between bidirectional LSP, unidirectional domain in the territory that the PCE in territory, upstream calculates according to self, calculate new VSPT and send to the PCE in self territory, upstream, until final VSPT is sent to source node by the PCE in territory, source node place;
Wherein, in the described territory calculated according to self, between bidirectional LSP and unidirectional domain, link paths calculating VSPT is:
PCE calculate this territory all enter bidirectional LSP in boundary node to the territory of destination node, PCE calculate territory, upstream to this territory unidirectional domain between link paths, by territory between bidirectional LSP and unidirectional domain link paths splice, obtain VSPT.
2. method according to claim 1, is characterized in that, link paths and described VSPT between bidirectional LSP, unidirectional domain in the territory that the PCE in territory, described upstream calculates according to self, and calculating new VSPT is:
PCE calculate this territory all enter boundary node to this territory all go out boundary node territory in bidirectional LSP, PCE calculate territory, upstream to this territory unidirectional domain between link paths; By in territory between bidirectional LSP and unidirectional domain link paths splice, and then splice downstream domain PCE send VSPT, obtain new VSPT.
3. method according to claim 1, is characterized in that, the method comprises further:
The PCE in intermediate field or first territory to this territory to downstream domain autonomous system (AS) unidirectional domain between link paths carry out authenticate reverse, if be proved to be successful, then execution route is not deleted, if authentication failed, then link paths between this unidirectional domain in described VSPT is deleted, the VSPT after having verified is sent to the PCE in territory, upstream.
4. computational methods for multi-domain two-way label switched path, is characterized in that, the method comprises:
After the PCE in territory, destination node place receives PCReq message, calculate the multiple domain bidirectional LSP of self, obtain VSPT, described VSPT is sent to the PCE in territory, upstream;
The PCE in territory, upstream calculates new VSPT according to the multiple domain bidirectional LSP of the VSPT received and self calculating, and sends to the PCE in self territory, upstream, until final VSPT is sent to source node by the PCE in territory, source node place;
Wherein, the PCE in territory, described upstream calculates new VSPT according to the VSPT received and the multiple domain bidirectional LSP that self calculates is:
The VSPT that the PCE of the multiple domain bidirectional LSP after examination and downstream domain sends splices by PCE, generates new VSPT.
5. method according to claim 4, is characterized in that, the multiple domain bidirectional LSP of described calculating self is:
PCE calculate in territory, upstream all go out boundary node in this territory all go out the multiple domain bidirectional LSP of boundary node.
6. method according to claim 4, is characterized in that, the method also comprises:
PCE carries out examination process to the multiple domain bidirectional LSP calculated.
7. method according to claim 6, is characterized in that, described PCE carries out examination to the multiple domain bidirectional LSP calculated and is treated to:
Check whether link circuit resource, the territory, upstream of the two-way link in territory meet the demands to the link circuit resource of the unidirectional domain-to-domain link in this territory, are deleted by the link do not met the demands from the multiple domain bidirectional LSP calculated;
Or, check the link circuit resource of the two-way link in territory, whether territory, upstream meet the demands to the link circuit resource of the unidirectional domain-to-domain link in this territory to the link circuit resource of the unidirectional domain-to-domain link in this territory, downstream domain, the link do not met the demands is deleted from the multiple domain bidirectional LSP calculated;
Or, check the two-way resource of two-way link in this territory, check whether downstream domain meets the demands to the link circuit resource of the unidirectional domain-to-domain link in this territory, is deleted by the link do not met the demands from the multiple domain bidirectional LSP calculated.
8. a computing system for multi-domain two-way label switched path, is characterized in that, this system comprises: the PCE in the PCE in territory, destination node place, the PCE in territory, upstream, territory, source node place; Wherein,
The PCE in territory, destination node place, after receiving PCReq message, in the territory calculated according to self, between bidirectional LSP and unidirectional domain, link paths calculates VSPT, and described VSPT is sent to the PCE in territory, upstream;
The PCE in territory, upstream, for link paths and described VSPT between bidirectional LSP, unidirectional domain in the territory that calculates according to self, calculates new VSPT and sends to the PCE in self territory, upstream;
The PCE in territory, source node place, for sending to source node by final VSPT;
Wherein, in the described territory calculated according to self, between bidirectional LSP and unidirectional domain, link paths calculating VSPT is:
PCE calculate this territory all enter bidirectional LSP in boundary node to the territory of destination node, PCE calculate territory, upstream to this territory unidirectional domain between link paths, by territory between bidirectional LSP and unidirectional domain link paths splice, obtain VSPT.
9. a computing system for multi-domain two-way label switched path, is characterized in that, this system comprises: the PCE in the PCE in territory, destination node place, the PCE in territory, upstream, territory, source node place; Wherein,
The PCE in territory, destination node place, after receiving PCReq message, calculates the multiple domain bidirectional LSP of self, obtains VSPT, described VSPT is sent to the PCE in territory, upstream;
The PCE in territory, upstream, for calculating new VSPT according to the multiple domain bidirectional LSP of the VSPT received and self calculating, and sends to the PCE in self territory, upstream;
The PCE in territory, source node place, for sending to source node by final VSPT;
Wherein, the PCE in territory, described upstream calculates new VSPT according to the VSPT received and the multiple domain bidirectional LSP that self calculates is:
The VSPT that the PCE of the multiple domain bidirectional LSP after examination and downstream domain sends splices by PCE, generates new VSPT.
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