CN100450088C

CN100450088C - Method for implementing bidirectional flow engineering tunnel

Info

Publication number: CN100450088C
Application number: CNB2005101024841A
Authority: CN
Inventors: 李贺军
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2005-09-14
Filing date: 2005-09-14
Publication date: 2009-01-07
Anticipated expiration: 2025-09-14
Also published as: CN1863151A; WO2007030988A1

Abstract

The present invention relates to a method for realizing bidirectional flow engineering tunnels. The present invention has the core that when two routers respectively establish destinations which are single-direction tunnels of the other parties, binding objects in the resource pre-reserved protocol-flow engineering RSVP-TE protocol are set; the respectively established destinations which are the single-direction tunnels of the other parties are bound on the basis of the expansion of the set RSVP-TE protocols. Through the bidirectional tunnel established by the present invention, the original service application of RSVP-TE can be supported, the bidirectional tunnel can flexibly and conveniently provide three-layer virtual private network VPN service like a generic routing encapsulation GRE tunnel, and the VPN has bandwidth guaranty and attributes of TE.

Description

Realize the method for bidirectional flow engineering tunnel

Technical field

The present invention relates to the communications field, relate in particular to a kind of method that realizes bidirectional flow engineering tunnel.

Background technology

RSVP-TE (RSVP-traffic engineering) agreement is the expansion to traditional RSVP (RSVP) agreement, is used for realizing traffic engineering at the MPLS/IP network.RSVP-TE can set up TE (traffic engineering) tunnel based on the constraint route, and be this TE (traffic engineering) tunnel bandwidth reserved as being a kind of tag distribution protocol.The FRR of RSVP-TE (fast heavy-route) mechanism and LSP (label switched path) back mechanism in addition can guarantee the reliability of traffic engineering tunnel.

Present prior art one related to the present invention, its core is to utilize GRE (generic route encapsulation) technology to set up bidirectional tunnel.Router R1 sets up tunnel interface, and source address is the IP address of R1, and destination address is the IP address of router R2; R2 sets up tunnel interface too, and source address is the IP address of R2, and destination address is the IP address of R1; The source in the last tunnel of R1, destination address destination address, the source address with the last tunnel of R2 respectively are identical.When R1 and R2 send the tunnel and set up request message to the other side, after the other side confirms, back response message, the process of setting up bidirectional tunnel finishes.

Can make up L3VPN (layer 3 VLAN) by tactful route or virtual router technology on the basis of the described bidirectional tunnel of having set up, this L3VPN has following shortcoming:

1, in GRE encapsulation and the decapsulation process, need CPU to handle, thereby forwarding performance is lower.Conciliate encapsulation process though adopt network processing unit (NP) to carry out the GRE encapsulation, can improve forward efficiency to a certain extent, equipment cost can significantly improve.

2, the gre tunneling technology adopts the VPN data is packaged in mode in the new IP message as payload, can increase a large amount of overhead bits.

3, gre tunneling does not have bandwidth assurance, traffic engineering mechanism, only relies on GRE technology itself to provide and has the vpn service that bandwidth guarantees.

4, the gre tunneling reliability depends on the routing convergence speed of dynamic routing protocol, can't reach 50 milliseconds carrier class link failure recovery time requirement.

Has the vpn service that bandwidth guarantees in order to provide, and raising forward efficiency, the technical scheme of prior art related to the present invention two has been proposed, its core is to utilize the RSVP-TE agreement to set up based on the unidirectional traffic engineering tunnel that bandwidth guarantees that has that retrains route, and, provide to have the vpn service that bandwidth guarantees in conjunction with RFC 2547bis MPLS/BGP VPN technologies structure L3VPN.

By the technical scheme of prior art two as can be seen, there is following defective in it:

Because the tunnel that RSVP-TE sets up is unidirectional, so can not be as gre tunneling, only just can make up L3VPN, also must have the vpn service that bandwidth guarantees in conjunction with providing with RFC 2547bisMPLS/BGP VPN technologies by tactful route or virtual router technology.Thereby realize and configuration complicated.

Summary of the invention

The purpose of this invention is to provide a kind of method that realizes bidirectional flow engineering tunnel, two-way traffic engineering tunnel by the present invention's foundation, not only can support the original service application of RSVP-TE, but also can be as gre tunneling, by virtual router technology or tactful route technology, provide to have the L3VPN business that bandwidth guarantees.

The objective of the invention is to be achieved through the following technical solutions:

The invention provides a kind of method that realizes bidirectional flow engineering tunnel, comprising:

A, when two routers are set up the destination separately for the other side's unidirectional tunnel, the bound object in resource allocation reservation protocol-traffic engineering RSVP-TE agreement;

B, based on the RSVP-TE protocol extension of described configuration, the destination that both sides set up is separately bound for the other side's unidirectional tunnel.

Wherein, described step B specifically comprises:

B1, router R1 give end-to-end router R2 by the RSVP-TE agreement transmit path message that configures;

B2, described R2 receive described message, according to described message processing are bound in the tunnel of R1 configuration, and loopback is reserved Resv message and given R1 then;

After B3, described R1 receive the Resv message of response, whether successful according to described Resv message authentication opposite end R2 with the tunnel binding of local terminal foundation, if confirm successfully, then finish this process, otherwise continue execution in step B1.

Wherein, described step B2 specifically comprises:

B21, described R2 receive described message;

Whether B22, the binding elements of analyzing in the described message satisfy condition, if all satisfy condition, then the destination of tunnel that the opposite end need be set up and self foundation is that the tunnel binding of R1 is a bidirectional tunnel, and in Resv message bound object is set, and responds then and gives R1; Otherwise, to ignore bound object, and respond Resv message and give R1, described Resv message is not carried bound object.

Wherein, described binding elements comprises:

The title in RSVP-TE tunnel, opposite end to be bound, the destination address and/or the source address of session object.

Wherein, the process that whether satisfies condition of the binding elements in the bound object in the described message of described analysis specifically comprises:

Whether the title that described R2 analyzes the RSVP-TE tunnel, opposite end to be bound in the bound object in the described message is consistent with the title in the local RSVP tunnel of setting up, if unanimity then satisfies condition; Otherwise, do not satisfy condition;

And/or,

Whether the destination address that described R2 analyzes session object in the described message is the source address in the local RSVP-TE tunnel of setting up, if then satisfy condition; Otherwise, do not satisfy condition;

And/or,

Whether the source address that described R2 analyzes session object in the described message is the destination address in the local RSVP-TE tunnel of setting up, if then satisfy condition; Otherwise, do not satisfy condition.

Wherein, described binding elements also comprises: the binding sign.

Wherein, among the step B22, the described process that bound object is set in Resv message specifically comprises:

To in the described Resv message bound object be set, and the title in the RSVP-TE tunnel, opposite end to be bound in the described bound object to be set to the destination that R2 sets up be the title of the unidirectional tunnel of R1, the binding sign is set to acknowledgement indicator;

And,

Distribute label and be set to common label.

Wherein, among the step B3, the process of described tunnel binding success of whether having set up with local terminal according to described Resv message authentication opposite end R2 specifically comprises:

B31, described R1 analyze described Resv message, when not carrying bound object in finding described Resv message, confirm that then bidirectional tunnel do not bind success; Otherwise, execution in step B32;

Whether B32, the title of analyzing the RSVP-TE tunnel, opposite end to be bound in the bound object that carries in the described Resv message are the title that the tunnel is set up in the opposite end, if, execution in step B33 then; Otherwise, think that bidirectional tunnel do not bind success;

Whether B33, the binding sign of analyzing in the bound object that carries in the described Resv message are the sign of confirming, if confirm that then bidirectional tunnel binds successfully; Otherwise, think that bidirectional tunnel do not bind success.

As seen from the above technical solution provided by the invention, among the present invention, when both sides' router is that RSVP-TE (RSVP-traffic engineering) on the unidirectional tunnel of opposite end is when agreement is configured to the destination of setting up separately, by the bound object of expansion of configuration RSVP-TE, the destination that both sides set up is separately bound for the other side's unidirectional tunnel.At the bidirectional tunnel that the present invention sets up, not only can support original all service application of RSVP-TE, and,, provide to have the L3 vpn service that bandwidth guarantees by virtual router technology or tactful route technology as gre tunneling.

Description of drawings

Fig. 1 is a flow chart of the present invention;

Fig. 2 is for realizing the principle schematic of virtual router by the RSVP-TE bidirectional tunnel.

Embodiment

The invention provides a kind of method that realizes bidirectional flow engineering tunnel, its main thought is: with reference to GRE bidirectional tunnel realization mechanism, utilize traffic engineering tunnel source address, destination address and the traffic engineering tunnel title of carrying in the protocol massages of RSVP-TE to realize the binding of two unidirectional traffic engineering tunnels.Can identify the packet that different traffic engineering tunnels pass over for the EGRESS node that guarantees traffic engineering tunnel simultaneously, can not use the last two jump ejecting mechanism when RSVP-TE carries out label distribution on EGRESS (outlet) node, and adopting the distribution common label, the message of different like this traffic engineering tunnels arrives the EGRESS node and is still carrying the different labels that EGRESS distributes afterwards.

Embodiment provided by the invention as shown in Figure 1, comprising:

Step 101 is provided with bound object in existing standard RSVP-TE agreement, be used to be provided with binding logo.

For realizing the present invention, need expand existing RSVP-TE agreement.Increase a bound object (Binding Object) newly, be defined as follows:

Class=TBD (still undefined), C_Type=TBD (still undefined)

0 1 2 3

0?1?2?3?4?5?6?7?8?9?0?1?2?3?4?5?6?7?8?9?0?1?2?3?4?5?6?7?8?9?0?1

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| Reserved | flag | Name?Length |

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| |

// Session?Name (NULL?padded?display?string) //

| |

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Wherein,

Reserved:16 position reserved field is necessary for 0.

Flag:8 bit flag field is defined as follows at present:

0x1 requires the binding sign, and is only effective in Path message;

0x2 binds successfully and confirms, and is only effective in Resv message.

Name Length:Session title length.

Session Name: opposite end RSVP Tunnel title to be bound.

Based on above-mentioned setting, the present invention can realize two-way traffic engineering tunnel based on the RSVP-TE agreement after the expansion, and the specific implementation step is as follows:

Step 102, when both sides' router PE is configured the RSVP RSVP on the unidirectional tunnel of setting up separately, the bound object among the configuration RSVP.

After the RSVP configuration of local R1 by existing mode configured tunneling technique A (Tunnel A), increase binding configuration of the present invention again, binding elements in the bound object in the configuration protocol, title, destination address and three kinds of information of source address of comprising RSVP-TE tunnel, opposite end to be bound with binding elements are example, and need indicate this moment needs RSVP-TE tunnel, the opposite end name of binding to be called tunnel B (Tunnel B); The source address that indicates the Session Object (session object) that the RSVP message carries simultaneously is the address of Tunnel A, and destination address is the address of Tunnel B.Certainly binding elements is not limited to above-mentioned tlv triple.

Simultaneously, opposite end R2 also needs to carry out similar configuration, and promptly indicating needs RSVP-TE tunnel, the opposite end name of binding to be called Tunnel A.The source address that indicates Session Object simultaneously is the address of Tunnel B, and destination address is the address of Tunnel A.

Sending the RSVP message with R1 below is the example explanation to R2, the process of the Tunnel B of Tunnel A and self foundation being bound at the R2 end.

Step 103, router R1 sends message packet to end-to-end router R2 by the RSVP-TE agreement that configures.

Existing RSVP configuration and the present invention that R1 finishes TunnelA bind after the configuration, RSVP will send the Path message packet to opposite end R2, wherein carry the Binding Object of new expansion, the Session Name of this Object is the title in the corresponding RSVP-TE tunnel of opposite end PE, and length then is the length of this Name; The requirement binding sign of the flag field among the Bindding Object is set to 1.

Step 104, intermediate router is transmitted the message packet that R1 sends.

Step 105, after described R2 receives described message, whether the binding elements of analyzing in the described message satisfies condition, if all satisfy condition, then execution in step 106, being about to the tunnel that need set up the opposite end and the tunnel binding of self setting up is bidirectional tunnel, and in Resv message bound object is set, and responds then to R1; Otherwise execution in step 107 is promptly ignored bound object, and responds Resv message and give R1, and described Resv message is not carried bound object.

After described R2 receives described message, according to Session Object (session object) in the described message and Binding Object (bound object), check whether following condition all meets: still comprise that with binding elements the title in RSVP-TE tunnel, opposite end to be bound, destination address and/or three kinds of information of source address of Session Object are example, the present invention's process that whether binding elements satisfies condition in analyzing described message is described, specific as follows:

Whether the title that described R2 analyzes the RSVP tunnel, opposite end to be bound in the bound object in the described message is consistent with the title in the local RSVP tunnel of setting up, if unanimity then satisfies condition; Otherwise, do not satisfy condition;

Whether the destination address that described R2 analyzes Session Object in the bound object in the described message is the source address in the local RSVP tunnel of setting up, if then satisfy condition; Otherwise, do not satisfy condition;

Whether the source address that described R2 analyzes Session Object in the bound object in the described message is the destination address in the local RSVP tunnel of setting up, if then satisfy condition; Otherwise, do not satisfy condition.

If all satisfy above condition, described R2 thinks that then the Path message of the TunnelA that receives requires TunnelA and TunnelB are bound bidirectional tunnel, so tunnel that the opposite end need be set up and the tunnel binding of self setting up are bidirectional tunnel, and structure Resv message (described structure Resv message specifically is meant existing Resv message is transformed, bound object is set):

To in the described Resv message bound object be set, and the title in the RSVP-TE tunnel, opposite end to be bound in the described bound object is set to the title of the unidirectional tunnel that R2 sets up, the binding sign of flag field is set to acknowledgement indicator, promptly is set to 1; And no longer distribute the IMPLICIT NULL label that requires the last two jump to eject, be set to common label and distribute label.

To respond to R1 through above-mentioned posttectonic Resv message.

When above-mentioned condition did not satisfy by one, described R2 can ignore bound object, and responded Resv message and give R1, and this moment, described Resv message was not carried bound object.

Step 108, intermediate router is transmitted the message packet that R2 sends.

After step 109, described R1 receive the Resv message of response, whether successful according to described Resv message authentication opposite end R2 with the tunnel binding of local terminal foundation, if confirm that successfully then execution in step 110, promptly finish this process, otherwise continue execution in step 103.Specifically comprise:

After step 1, described R1 receive the Resv message of response, analyze described Resv message, when in finding described Resv message, not carrying bound object, confirm that then bidirectional tunnel do not bind success; Otherwise, execution in step 2;

Whether the title in the RSVP-TE tunnel, opposite end to be bound in the bound object that carries in step 2, the described Resv message of analysis is the title that the tunnel is set up in the opposite end, if then execution in step 3; Otherwise, think that bidirectional tunnel do not bind success, change step 103 then over to;

Whether step 3, the binding sign of analyzing in the bound object that carries in the described Resv message are the sign of confirming, if confirm that then bidirectional tunnel binds successfully; Otherwise, think that bidirectional tunnel do not bind success, change step 103 then over to.

Flow process on the R2 of opposite end and local R1 are similar, are not described in detail here.

When LSR-A and LSR-B all successfully carried out binding and for the opposite end affirmation after, the RSVP Tunnel of whole binding has just set up.

By the specific embodiments of the invention described above as can be seen, RSVP-TE is through after the protocol extension, and RSVP-TE has incorporated the advantage of the bidirectional tunnel that GRE and IPsec have on the basis of numerous advantages such as existing QoS, TE and reliability.

Utilize RSVP-TE bidirectional tunnel technology provided by the invention, except supporting the original service application of RSVP-TE, can also support all service application that gre tunneling is supported, for example, virtual router functionality, as the outer layer tunnel of MPLS VPN, with by two routed domain of separating of osi tunnel or the like.Can provide L3 vpn service easily by virtual router or tactful route, this L3VPN technology has QoS assurance, TE and the reliability advantage of RSVP-TE and the advantage that the GRE bidirectional tunnel is conveniently set up VPN concurrently.

Below only be example with the virtual router functionality, the using method of simple declaration RSVP-TE bidirectional tunnel.

Utilize method that the two-way traffic engineering tunnel technology of RSVP-TE realizes virtual router as shown in Figure 2, set up two virtual router example VRF Red and VRF Blue on PE-1 and the PE-2 respectively.PE-1, PE-2 connect the interface of two CE equipment and bind virtual router example VRF Red and VRFBlue respectively.Between PE-1 and PE-2, set up two two-way traffic engineering tunnel Tunnel 1 and Tunnel 2, bind virtual router example VRF Red and VRF Blue respectively, by configuring static route or dynamic routing on the virtual router example, be linked between the CE equipment of identical virtual router example on two PE equipment and just can have visited mutually.

The above, only for the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto, and binding elements for example of the present invention is not limited only to tunnel title, source address and destination address tlv triple.Bind the way of bidirectional tunnel by two unidirectional tunnels of other binding elements realization; be that any those skilled in the art of being familiar with are in the technical scope that the present invention discloses; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of claim.

Claims

1, a kind of method that realizes bidirectional flow engineering tunnel is characterized in that, comprising:

2, method according to claim 1 is characterized in that, described step B specifically comprises:

3, method according to claim 2 is characterized in that, described step B2 specifically comprises:

B21, described R2 receive described message;

4, method according to claim 3 is characterized in that, described binding elements comprises:

5, method according to claim 4 is characterized in that, the process whether binding elements in the bound object in the described message of described analysis satisfies condition specifically comprises:

And/or,

According to the method for claim described 3, it is characterized in that 6, described binding elements also comprises:

The binding sign.

According to the method for claim described 6, it is characterized in that 7, among the step B22, the described process that bound object is set specifically comprises in Resv message:

And,

Distribute label and be set to common label.

8, method according to claim 2 is characterized in that, among the step B3, the process of described tunnel binding success of whether having set up with local terminal according to described Resv message authentication opposite end R2 specifically comprises: