Background technology
Along with development of internet technology, multiprotocol label switching (Multi-Protocol Label Switching, MPLS) Virtual Private Network (Virtual Private Network, VPN) be widely used in metropolitan area network, backbone network, except being used to carry VPN user and big customer's business, also be used to carry the key business of telecommunications self such as the 3rd third-generation mobile communication (3G), soft switch.Because more and more multiple services the development makes operator more and more pay attention to the cross-domain demand of VPN.
In the cross-domain application scenarios of MPLS VPN, for inter-domain link fault, Autonomous System Boundary Router, AS Boundary Router (Autonomous System Boundary Router occurring, ASBR) during problem such as equipment fault, prior art is carried out routing convergence and is comprised local ASBR routing convergence and far-end ASBR routing convergence.
One, local ASBR routing convergence:
ASBR inter-domain routing schematic diagram when as shown in Figure 1, illustrating the cross-domain deployment of present vpn service; Among Fig. 1, autonomous system (Autonomous System, AS) 1 and AS2 be two mpls domains, (Multi-Protocol External Border GatewayProtocol, MP-EBGP) (Option B scheme) realizes the cross-domain exchange of VPN routing iinformation by setting up single-hop multi-protocols External BGP therebetween.Wherein, the client boundary router (Client Edge, CE) 1 and CE3 belong to VPN1, dual-homed two the network provider border routers of CE3 (Provider Edge, PE) equipment, i.e. PE3 among Fig. 1, PE4.CE2 and CE4 belong to VPN2, and CE4 is dual-homed to two PE equipment, i.e. PE3 among Fig. 1, PE4.
In AS1, set up Internal BGP (Interior Border Gateway Protocol between PE1 and PE2, PE1 and ASBR1, PE2 and ASBR2, ASBR1 and the ASBR2 respectively, IBGP) neighborhood supposes that ASBR1 and ASBR2 are local ASBR equipment; In AS2, set up the IBGP neighborhood between PE3 and PE4, PE3 and ASBR3, PE4 and ASBR4, ASBR3 and the ASBR4 respectively, suppose that ASBR3 and ASBR4 are far-end ASBR equipment.Between AS1 and AS2, set up outside routing gateway agreement (External BorderGateway Protocol between ASBR1 and ASBR3, ASBR2 and the ASBR4 respectively, EGBP) neighborhood, ASBR1 can receive the VPN route of ASBR3 issue, it is the VPN route 1 among Fig. 1, simultaneously, ASBR1 can also receive the VPN route of ASBR4 through the ASBR2 issue, it is the VPN route 2 among Fig. 1, succinct in order to describe, do not mark any network provider router (Provider, P router) among Fig. 1.The two-way forwarding testing mechanism of running boundary gateway protocol (BFD for BGP) between ASBR1 and ASBR3, realization equipment and link failure detect in real time.
With the VPN1 route is example, and the main flow process of local ASBR routing convergence is: after supposing that flow arrives ASBR1 from CE1, and the preferred VPN route 1 cross-domain converting flow of ASBR1.Fig. 2 is existing a kind of local ASBR routing convergence schematic diagram when the cross-domain deployment of vpn service, as shown in Figure 2, when in the flow repeating process, link failure between ASBR3 equipment fault or ASBR1 and the ASBR3, so, ASBR1 can pass through this fault of the quick perception of BFD for BGP, directly triggers this locality convergence of VPN route then, comprising:
ASBR1 carries out routing optimization again, with ASBR4 through the VPN route 2 of ASBR2 issue as preferred route; ASBR1 to Forwarding plane, removes the route of former ASBR3 issue with new preferred route sending-down simultaneously; After the forwarding-table item of Forwarding plane upgraded, after flow arrived ASBR1, the preferred VPN route 2 cross-domain converting flows of meeting were to CE3, thus the convergence again of the cross-domain business of realization VPN.
Yet, in the existing local ASBR routing convergence process:
ASBR1 after awareness apparatus or the link failure, reports interface board by BFD in 30ms, need usually about 100ms;
Interface board notice master control borad, the convergence of announcement bgp protocol needs about hundreds of millisecond to 1 second usually;
Again busy with the VPN number of routes what of spare time of ASBR1 control plane are also depended in the convergence of route, that is: chain of command is busy, and the VPN number of routes is more, all will reduce the convergence rate of VPN route to a certain extent.
As seen, existing local ASBR routing convergence speed is very slow, and for the exigent business of real-times such as voice, video, the user is unacceptable.
Two, far-end ASBR routing convergence:
Route schematic diagram in the far-end ASBR territory when as shown in Figure 3, illustrating the cross-domain deployment of present vpn service.Among Fig. 3, autonomous system (Autonomous System, AS) 1 and AS2 be two mpls domains, realize the cross-domain exchange of VPN routing iinformation by setting up single-hop MP-EBGP (Option B scheme) therebetween.Wherein, the client boundary router (Client Edge, CE) 1 and CE3 belong to VPN1, dual-homed two the network provider border routers of CE3 (Provider Edge, PE) equipment, i.e. PE3 among the figure, PE4.CE2 and CE4 belong to VPN2, and CE4 is dual-homed to two PE equipment, i.e. PE3 among the figure, PE4.
In AS1, set up the IBGP neighborhood between PE1 and PE2, PE1 and ASBR1, PE2 and ASBR2, ASBR1 and the ASBR2 respectively, suppose that ASBR1 and ASBR2 are local ASBR equipment; In AS2, set up the IBGP neighborhood between PE3 and PE4, PE3 and ASBR3, PE4 and ASBR4, ASBR3 and the ASBR4 respectively, suppose that ASBR3 and ASBR4 are far-end ASBR equipment.ASBR3 can receive the VPN route of PE3 issue, i.e. VPN route 3 among the figure, and simultaneously, ASBR3 can also receive the VPN route of PE4 through the ASBR4 issue, and promptly the VPN route 4 among the figure is succinct in order to describe, and does not mark any P router among the figure.Operation BFD for BGP between ASBR3 and PE3, realization equipment and link failure detect in real time.
With the VPN1 route is example, and the main flow process of far-end ASBR routing convergence is: suppose flow behind the cross-domain arrival of CE1 ASBR3, the preferred VPN route 3 of ASBR3 continues converting flow.As shown in Figure 4, when in the flow repeating process, link failure between PE3 equipment fault or ASBR3 and the PE3, so, ASBR3 can pass through this fault of the quick perception of BFD for BGP, directly triggers this locality convergence of VPN route then, comprising:
ASBR3 carries out routing optimization again, with PE4 through the VPN route 4 of ASBR4 issue as preferred route; ASBR3 to Forwarding plane, removes the VPN route 3 of former PE3 issue with new preferred route sending-down simultaneously; After the forwarding-table item of Forwarding plane upgraded, behind the cross-domain arrival of the flow ASBR3, preferred VPN route 4 converting flows of meeting were to CE3, thus the convergence again of realization vpn service.
Yet, in the existing far-end ASBR routing convergence process:
ASBR3 after awareness apparatus or the link failure, reports interface board by BFD in 30ms, need usually about 100ms;
Interface board notice master control borad, the convergence of announcement bgp protocol needs about hundreds of millisecond to 1 second usually;
Again busy with the VPN number of routes what of spare time of ASBR3 control plane are also depended in the convergence of route, that is: chain of command is busy, and the VPN number of routes is more, all will reduce the convergence rate of VPN route to a certain extent.
As seen, very slow in existing far-end ASBR routing convergence speed, for the exigent business of real-times such as voice, video, the user is unacceptable.
In sum, in realizing process of the present invention, the inventor finds in the cross-domain application scenarios of MPLS VPN, when problems such as inter-domain link fault, ASBR equipment fault occurring, ASBR routing convergence speed is slower, for real time business, has a strong impact on its service quality (Quality of Service, QoS), can't meet consumers' demand.
Embodiment
A kind of method that in MPLS VPN, realizes quick heavy-route that the embodiment of the invention proposes, by two routes being generated primary and backup label switched path (Label Switch Path, LSP), and be issued in the forwarding-table item simultaneously, select conversion link by inquiring about the master with the state of LSP, when the master uses lsp failure, immediately flow is switched to standby LSP, to realize quick heavy-route, comprise at least in the specific implementation: carry out route selecting when routing configuration, converting flow, carry out routing convergence when breaking down.
With reference to figure 5, illustrate the flow chart of routing configuration in the method that realizes quick heavy-route among a kind of MPLS VPN of the embodiment of the invention, specifically comprise:
Step S11, boundary routing device receive at least two VPN routes, and as primary route, a VPN route is as alternate routing with a VPN route;
Step S12, described primary route and alternate routing generate main with LSP and standby LSP respectively together with label (comprise label or territory interior label between the territory, wherein, label or territory interior label comprise outgoing label and go into label between described territory) together, wherein, go into two LSP of the corresponding active and standby usefulness of label for one;
Step S13, during the main MPLS that is installed to described boundary routing device simultaneously with LSP and standby LSP transmitted, wherein, and described transmitting as shown in figure 11, its list item comprises at least: the state of going into label, outgoing label, next jumping, outgoing interface, main usefulness LSP.
Step S14 moves BFD on leading with LSP, carry out link detecting.
When described border router receives the MPLS message, in the time of need carrying out flow (or message) forwarding, carry out route selecting, as shown in Figure 6, illustrate the flow chart of route selecting in the method that realizes quick heavy-route among a kind of MPLS VPN that the embodiment of the invention proposes, comprising:
Step S21, the searching label master who carries according to flow in MPLS transmits uses the state of LSP, particularly, and in conjunction with Figure 11, the label that carries with described flow during the label lookup of carrying according to flow is transmitted is corresponding goes into label, thereby obtains the main state with LSP that this goes into the label correspondence;
Step S22 judges whether described main state with LSP is effective, when judged result when being, execution in step S23, otherwise execution in step S24;
Step S23 chooses the main LSP converting flow of using;
Step S24 chooses standby LSP converting flow.
In the present embodiment, carry out choosing of flow forward-path, when the master is unavailable with LSP, can in time flow be switched to standby LSP, realize convergence fast by judging main state with LSP.
When in the flow repeating process, in step S14, be checked through link failure or equipment fault by BFD, need carry out routing convergence, as shown in Figure 7, comprising:
Step S31, BFD detect the master and use lsp failure, comprising: link failure or equipment fault;
Step S32, main state with LSP was invalid during modification MPLS transmitted, that is: the state that will lead with LSP is changed to down, and reports key-course;
Step S34, in the flow repeating process, as shown in Figure 6, MPLS transmits by inquiry, and finding main is down with the LSP state, that is: invalid;
Step S35 chooses standby LSP and carries out the flow forwarding.
By operation BFD, guarantee in 30ms, to finish fault detect, in case detect the main lsp failure of using, upgrade in time and transmit middle main state, realize quick heavy-route, guarantee the quick convergence of 50ms with LSP, improved convergence rate, reduce time delay, improved the user experience of real-time service, guaranteed service quality.
In order further to set forth a kind of method that in MPLS VPN, realizes quick heavy-route of the present invention, below in conjunction with accompanying drawing, respectively between the ASBR territory fast heavy-route (Fast ReRoute, two aspects of FRR describe FRR) and in the ASBR territory.
With reference to figure 8, illustrate and realize fast rerouting method application scenarios figure between the ASBR territory among a kind of MPLS VPN of the embodiment of the invention.
Among the figure, AS1 and AS2 are two mpls domains, realize the cross-domain exchange of VPN routing iinformation by setting up single-hop MP-EBGP (OptionB scheme) therebetween.Wherein, CE1 and CE3 belong to VPN1, dual-homed two the PE equipment of CE3, i.e. PE3 among the figure, PE4.CE2 and CE4 belong to VPN2, and CE4 is dual-homed to two PE equipment, i.e. PE3 among the figure, PE4.In AS1, set up the IBGP neighborhood between PE1 and PE2, PE1 and ASBR1, PE2 and ASBR2, ASBR1 and the ASBR2 respectively, suppose that ASBR1 and ASBR2 are local ASBR equipment; In AS2, set up the IBGP neighborhood between PE3 and PE4, PE3 and ASBR3, PE4 and ASBR4, ASBR3 and the ASBR4 respectively, suppose that ASBR3 and ASBR4 are far-end ASBR equipment.Between AS1 and AS2, set up the EGBP neighborhood between ASBR1 and ASBR3, ASBR2 and the ASBR4 respectively, ASBR1 can receive the VPN route of ASBR3 issue, i.e. VPN route 1 among the figure, simultaneously, ASBR1 can also receive the VPN route of ASBR4 through the ASBR2 issue, i.e. VPN route 2 among the figure, succinct in order to describe, do not mark any P router among the figure.Operation BFD for BGP between ASBR1 and ASBR3, realization equipment and link failure detect in real time.
In embodiments of the present invention, the VPN route 1 that ASBR1 chooses the ASBR3 issue usually is primary route, and the VPN route 2 of choosing the ASBR4 issue is alternate routing, and combines with AS1 territory interior label, generates main with LSP1 and standby LSP2 respectively.ASBR1 will lead with LSP1 and standby LSP2 and be issued to simultaneously during MPLS transmits.
Under normal circumstances, flow is transmitted cross-domain flow rate to ASBR3 by LSP1, the link failure between ASBR3 device fails or ASBR1-ASBR3 after arriving ASBR1 from CE1, and ASBR1 is by after the quick perception of BFD, trigger FRR between the territory immediately, flow is switched on the standby LSP2, that is: after flow arrives ASBR1 from CE1, transmit cross-domain flow rate to CE3 by LSP2, thereby, guarantee that the 50ms of flow switches fast, greatly improved the convergence rate of cross-domain vpn service.
Wherein, trigger FRR between the territory, flow switched on the standby LSP2 be specially: that will transmit mainly is changed to down with the LSP1 state, when flow arrives, find that by inquiring about described transmitting main state with LSP1 is down, then enable the standby LSP2 of MPLS in transmitting immediately and carry out the flow forwarding.
With reference to figure 9, illustrate and realize fast rerouting method application scenarios figure in the ASBR territory among a kind of MPLS VPN of the embodiment of the invention.
Among the figure, AS1 and AS2 are two mpls domains, realize the cross-domain exchange of VPN routing iinformation by setting up single-hop MP-EBGP (OptionB scheme) therebetween.Wherein, CE1 and CE3 belong to VPN1, dual-homed two the PE equipment of CE3, i.e. PE3 among the figure, PE4.CE2 and CE4 belong to VPN2, dual-homed two the PE equipment of CE4, i.e. PE3 among the figure, PE4.In AS1, set up the IBGP neighborhood between PE1 and PE2, PE1 and ASBR1, PE2 and ASBR2, ASBR1 and the ASBR2 respectively, suppose that ASBR1 and ASBR2 are local ASBR equipment; In AS2, set up the IBGP neighborhood between PE3 and PE4, PE3 and ASBR3, PE4 and ASBR4, ASBR3 and the ASBR4 respectively, suppose that ASBR3 and ASBR4 are far-end ASBR equipment, ASBR3 can receive the VPN route of PE3 issue, i.e. VPN route 3 among the figure, simultaneously, ASBR3 can also receive the VPN route of PE4 through the ASBR4 issue, promptly the VPN route 4 among the figure is succinct in order to describe, and does not mark any P router among the figure.Operation BFD for BGP between ASBR3 and PE3, realization equipment and link failure detect in real time.
In embodiments of the present invention, the VPN route 3 that ASBR3 chooses PE3 issue usually is primary route, and the VPN route 4 of choosing the PE4 issue is alternate routing, and with the territory between label combine, generate main respectively with LSP3 and standby LSP4.ASBR3 will lead with LSP3 and standby LSP4 and be issued to simultaneously during MPLS transmits.
Under normal circumstances, flow behind the cross-domain arrival of CE1 ASBR3, by the LSP3 converting flow to CE3, the link occurs fault between PE3 device fails or ASBR3-PE3, and ASBR3 is by after the quick perception of BFD, trigger FRR in this territory immediately, flow is switched on the standby LSP4, that is: flow is behind the cross-domain arrival of CE1 ASBR3, transmit cross-domain flow rate to CE3 by LSP4, thereby, guarantee that the 50ms of flow switches fast, greatly improved the convergence rate of cross-domain vpn service.
Wherein, trigger FRR in this territory, flow switched on the standby LSP4 be specially: that will transmit mainly is changed to down with the LSP3 state, when flow arrives, find that by inquiring about described transmitting main state with LSP3 is down, then enable the standby LSP4 of MPLS in transmitting immediately and carry out the flow forwarding.
The embodiment of the invention described above shows between the ASBR territory or the scheme of configuration FRR in the territory, certainly, also can adopt between the ASBR territory and dispose FRR, and also dispose the scheme of FRR in the ASBR territory.
In one embodiment of the invention, dispose on the basis of FRR between above-mentioned ASBR territory and/or in the territory, can further on PE1, dispose VPN FRR, wherein, PE1 transmits as shown in figure 12, and its list item comprises: VPN route prefix, VPN route, private network tags, public network mark, next jumping, outgoing interface, the main state of using the LSP of VPN route correspondence;
In conjunction with Fig. 8 or Fig. 9, under normal circumstances, when receiving the flow of CE1 transmission, PE1 selects the main LSP converting flow of using of PE1-ASBR1 correspondence,
When PE1-ASBR1 link failure or ASBR1 equipment fault take place when; the 50ms that guarantees vpn service restrains fast; PE1 selects the standby LSP of PE1-PE2-ASBR2 correspondence to carry out the flow forwarding; realized the quick heavy-route on the PE1 like this; guaranteed the reliability in the AS1, in whole M PLS VPN, simultaneously in conjunction with FRR between the ASBR territory and the territory; can realize protecting end to end, improve whole system reliability and disaster tolerance.
Realize based on above-mentioned a kind of method that in MPLS VPN, realizes quick heavy-route that ASBR and link thereof break down and realize convergence fast, need carry out the function expansion corresponding apparatus.
As shown in figure 10, the embodiment of the invention has proposed a kind of routing device, and it comprises:
Transmit memory module 1020, be used for forwarding table memory, preserved main in described the transmitting with LSP, standby LSP information and main state with LSP; Wherein, when border router is ASBR, for instance, the structure of transmitting as shown in figure 11, its list item comprises at least: go into label, outgoing label, next jumping, outgoing interface, main state with LSP.
Enquiry module 1030, when being used for the flow forwarding, whether effective according to the described main state of searching label that flow carries with LSP, particularly, in conjunction with Figure 11, the label that carries with described flow during the label lookup of carrying according to flow is transmitted is corresponding goes into label, thereby obtains the main state with LSP that this goes into the label correspondence;
LSP chooses module 1040, is used for inquiring main state with LSP when effective when enquiry module 1030, chooses the main LSP converting flow of use, when enquiry module inquires the state of the main LSP of using when invalid, chooses standby LSP converting flow.
In another embodiment of the invention, described routing device also comprises:
LSP generation module 1010, two routes that are used for obtaining generate main with LSP and standby LSP respectively together with label.
In another embodiment of the invention, described routing device also comprises:
Whether fault detection module 1050 is used for detecting the master and breaks down with LSP;
Fault processing module 1060 is used for detecting mainly when breaking down with LSP when fault detection module 1050, transmits with described that main state with the LSP correspondence is changed to disarmed state in the memory module 1020, and reports key-course.
Need to prove that the described routing device of the embodiment of the invention specifically can comprise Autonomous System Boundary Router, AS Boundary Router (ASBR) or network provider (PE) border router.
In the above-described embodiments, to adopt BFD to realize fault detect, revising main state with LSP is the method and apparatus that example illustrates the quick heavy-route of realization of the present invention, the present invention is not limited thereto certainly, also can adopt Ethernet Operations, Administration and Maintenance (Operations, Administration and Maintenance OAM) realizes; If that LSP adopts is Synchronous Optical Network (Synchronous Optical Network, SONET)/synchronous digital transmission system (Synchronous Digital Hierarchy, SDH) (the Packet OverSONET/SDH of the grouping on, POS) link, usually by POS self alarming mechanism, realize fault detect, main state with LSP is revised in interlock.
In sum, according to the embodiment of the invention by two routes are generated primary and backup LSP, and be installed in the forwarding-table item simultaneously, select conversion link (main) by inquiring about the master with the state of LSP with LSP or standby LSP, and by between the territory between the ASBR, move BFD between ASBR and the PE in the territory, realize that two-way forwarding detects, fault detect speed is at Millisecond, guarantee in 30ms, to finish, and, upgrade in time and transmit, perhaps BFD detection and main with the interlock of LSP state, utilize self mechanism in tense situation or the OAM mechanism of POS link to realize quick fault testing, and upgrade in time and transmit, accelerate the triggering of FRR, flow is transmitted switched on the standby LSP, guarantee the quick convergence of 50ms, greatly improved the reliability when VPN is cross-domain, guaranteed QoS, can meet consumers' demand better.
The above is a preferred implementation of the present invention; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention; can also make some improvements and modifications, these improvements and modifications also are considered as protection scope of the present invention.