CN100550841C - Autonomous System Boundary Router, AS Boundary Router route issuing method and Autonomous System Boundary Router, AS Boundary Router - Google Patents

Abstract

The invention discloses a kind of Autonomous System Boundary Router, AS Boundary Router route issuing method, this method is: Autonomous System Boundary Router, AS Boundary Router ASBR is when the issue route, for next that receive jumped, outgoing label is identical respectively route assignment identical go into label, and described route is released.The invention also discloses a kind of Autonomous System Boundary Router, AS Boundary Router, this router mainly comprises: input unit, label distribution unit and output unit.Method and system provided by the present invention can be saved label resources, and can avoid creating a large amount of label exchange mapping ILM, save memory source.

Description

Autonomous System Boundary Router, AS Boundary Router route issuing method and Autonomous System Boundary Router, AS Boundary Router

Technical field

The present invention relates to route technology, relate in particular to route issuing method and a kind of Autonomous System Boundary Router, AS Boundary Router on a kind of Autonomous System Boundary Router, AS Boundary Router (ASBR).

Background technology

Border Gateway Protocol (BGP, Border Gateway Protocol) multiprotocol label is transmitted (MPLS, Multiple Protocol Label Switch) Internet Protocol (IP) Virtual Private Network (VPN, VirtulPrivate Network) be that BGP MPLS IP VPN is a kind of based on service provider edge router (PE, Provider Edge) 3 layers of VPN (L3VPN) technology, it uses BGP to issue the VPN route on service provider backbone, use MPLS on service provider backbone, to transmit the VPN message, networking mode is flexible, extensibility is good, uses also more and more widely.Referring to BGP MPLS IP VPN model schematic diagram shown in Figure 1, mainly comprise user network boundary device (CE, CustomerEdge), PE and service provider's network backbone router (P, Provider) three parts.Wherein, CE can be router, switch or main frame etc., have interface directly with the service provider (SP, ServiceProvider) network is continuous; PE is the edge device of service provider network, directly links to each other with CE, all occurs on the PE to all processing of VPN; P does not directly link to each other with CE, only need possess basic MPLS transfer capability, does not safeguard VPN information.

VPN instance (VPN-instance) is that PE is address (site) foundation that directly links to each other and a special entity of safeguarding, also claim a VPN route forwarding table (VRF, VPN Routing and Forwardingtable) or an addresses forwarding table (per-site forwarding table).VPN instance is corresponding with site, and each site has the VPN instance of oneself on PE, every corresponding VPN instance with the connection of PE of CE.Separate between each VPN instance on the PE, separate with the public network routing table, each VPN instance can be regarded as a virtual router, safeguard independently address space, the interface that is connected to this router is arranged.There is a plurality of transmitting on the PE, comprise a public network routing table and one or more VRF, comprise the route of all PE and P router in the public network routing table, comprise the route of direct-connected site in the VPN instance.

PE need be incorporated into these VPN routes in the public network routing table after receiving the 4th edition (IPv4) route of general the Internet agreement from CE, is distributed to other PE.Traditional B GP can't correctly handle the overlapping VPN route of address space, because BGP can't distinguish IP address prefix identical in the different VPN, for addressing this problem, BGP MPLS IP VPN has introduced VPN-IPv4 address family.The VPN-IPv4 address is totally 12 bytes, comprises the RD of 8 bytes and the IPv4 address prefix of 4 bytes, and wherein, RD is used to distinguish the IPv4 prefix of using same address space, and RD is that 0 VPN-IPv4 address is equivalent to common IPv4 address.PE is converted to the VPN-IPv4 route after receiving common IPv4 route from CE, carries out the transmission of VPN route on public network.Multiprotocol bgp (MP-BGP, Multiprotocolextensions for BGP-4) is used between pe router, propagating VPN and forms information and VPN-IPv4 route, MP-BGP is backward compatible, both can support traditional IPv4 address family, can support other address family again, as VPN-IPv4 address family, IPv6 address family etc.

During actual networking was used, a plurality of Site of a VPN of certain user may be connected to a plurality of service providers that use different autonomous system (AS), or a plurality of AS of a service provider, and the application mode that this VPN crosses over a plurality of AS is called cross-domain VPN.Proposed three kinds of cross-domain vpn solutions in the prior art, be respectively: cross-domain A (Inter-Provider Backbones Option A), cross-domain B (Inter-Provider Backbones Option B), cross-domain C (Inter-Provider BackbonesOption C).

In cross-domain B, the label VPN-IPv4 route that receives from the pe router of AS separately by MP-EBGP exchange between ASBR, referring to shown in Figure 2, the PE in the AS100 is distributed to label VPN-IPv4 route by the MP-IBGP mode border router ASBR1 of AS100 earlier; ASBR1 is distributed to label VPN-IPv4 route by the MP-EBGP mode border router ASBR2 of AS200; ASBR2 is distributed to PE in the AS200 to label VPN-IPv4 route by the MP-IBGP mode again.

Operation MP-EBGP agreement between two ASBR, the MP-EBGP agreement passes to the another one territory with all the VPN information in the territory, transmission be VPN route and label information.Distribution principle according to a label (Per-Instance), when next jumping (Nexthop) of a route when being changed, must change label in this locality, therefore, the VPN routing iinformation of ASBR in receiving the territory is when outwards issuing again, redistribute label must for these VPN routing iinformations, the VPN routing iinformation is accompanied by new label and is published away, and in ASBR this locality, new and old label forms the swap operation of a label.The ASBR of opposite end receives behind the next VPN routing iinformation of MP-EBGP, preserves in this locality, continues the PE equipment diffusion in own territory again.

Also for example the route issuing method among the cross-domain VPN is described below in conjunction with Fig. 3: ASBR1 receives VPN-IPv4 route 10.0.0.0/8 from PE 1, and next of this route jumped and be PE1, and the private network tags of carrying (Label) is L1; ASBR1 is to ASBR2 issue route the time, for route 10.0.0.0/8 redistributes label L2, and at this locality generation label exchange mapping ILM list item (InLabel/OutLabel:L2/L1), that is to say, going into label InLabel is L2, outgoing label OutLabel is L1, simultaneously next jumping is changed into the address ASBR1 of oneself.ASBR2 receives VPN-IPv4 route 10.0.0.0/8 from ASBR1, and next of this route jumped and be ASBR1, and the private network tags of carrying is L2; ASBR2 for route 10.0.0.0/8 redistributes label L3, and at this locality generation label exchange mapping ILM list item (InLabel/OutLabel:L3/L2), changes next jumping into the address ASBR2 of oneself simultaneously to PE2 issue route the time.

As seen, ASBR will redistribute a label for every VPN-IPv4 route in the prior art, be that each newly assigned label is all wanted the corresponding ILM of establishment simultaneously, and these ILM will be broadcast to each interface board.

But in actual applications, ASBR often needs to preserve and issue in the territory and overseas numerous VP N-IPv4 route, and this just need take a large amount of labels, creates a large amount of ILM.Because label resources is limited, and system also is limited to storage and the disposal ability of ILM, and therefore, the route issuing method among the existing cross-domain B causes the waste of label resources easily; In addition, on ASBR, create the burden that a large amount of ILM causes forwarding plane easily, and these ILM will be broadcast to each interface board, need constantly to refresh forwarding information between master control borad and the interface board, cause the waste of memory source easily, such label distribution mode may cause system can't satisfy the demand of some applied environment.

Summary of the invention

The object of the present invention is to provide route issuing method and a kind of Autonomous System Boundary Router, AS Boundary Router on a kind of ASBR, save label resources.

For achieving the above object, route issuing method provided by the invention is as follows:

Autonomous System Boundary Router, AS Boundary Router ASBR be the route assignment that next is jumped, outgoing label is identical respectively received identical go into label, and described route is released.

Wherein, described distribution comprises:

After A1, ASBR receive route, judge whether to exist and the issue route that next is jumped, outgoing label is identical respectively of this route, if exist, execution in step B1 then, otherwise, execution in step C1;

B1, go into label as the label of going into of receiving route, and the route of receiving is released the processing of process ends what this had issued route;

C1, go into label for the route assignment received, and the route of receiving is released.

Described step C1 further comprises: ASBR is according to the described outgoing label of receiving route and be the label of going into of this route assignment, generates label exchange mapping ILM list item.

Step C1 described for the route assignment received go into label and step B1 described issued route to go into label different.

ASBR sets up and comprises next jumping, the outgoing label of issuing route and the data structure of going into label and preservation, and described distribution comprises:

After A2, ASBR received route, next that judge this route jumped and whether outgoing label has been included in the described data structure, if, execution in step B2 then, otherwise, execution in step C2;

B2, ASBR with in the described data structure with receive that next jumping of route and outgoing label are corresponding and go into label, as the label of going into of receiving route, and the route of receiving released;

C2, ASBR are that the route assignment of receiving is gone into label, and the route of receiving is released.

Described step C2 further comprises: ASBR is according to the described outgoing label of receiving route and be the label of going into of this route assignment, generates label exchange mapping ILM list item; And receive next jumping, the outgoing label of route and go into label and preserve with described data structure form with described.

Step C2 described for the route assignment received go into label with adopt described data structure form preservation to go into label different.

Described distribution comprises: for route from same service provider edge router PE, ASBR be have the route assignment of identical outgoing label identical go into label;

For route from different PE, ASBR be have the route assignment of identical outgoing label and identical next jumping identical go into label.

Described route is the 4th edition VPN-IPv4 route of Virtual Private Network-Internet Protocol.

The present invention also provides a kind of Autonomous System Boundary Router, AS Boundary Router, and this router comprises: input unit, label distribution unit and output unit, wherein,

Input unit is used to receive route, and the route of receiving is sent to the label distribution unit;

The label distribution unit be used to the route assignment that next is jumped, outgoing label is identical respectively received identical go into label, and this route is sent to output unit;

The route that output unit is used for receiving releases.

This shows, among the present invention ASBR in issue during route, for the route assignment that next is jumped, outgoing label is identical respectively received identical go into label, rather than all redistribute a label for every route, can save label resources greatly like this.In addition, the present invention only needs new just to create ILM when going into label distributing, and can avoid creating a large amount of ILM, thereby alleviate the burden of forwarding plane, has reduced forwarding information refreshing between master control borad and interface board, has saved memory source.

Description of drawings

Fig. 1 is a BGP MPLS IP VPN model schematic diagram of the prior art.

Fig. 2 is a networking schematic diagram of issuing label VPN-IPv4 route in the prior art between ASBR by MP-EBGP.

Fig. 3 is a route issuing process schematic diagram of the prior art.

Fig. 4 is the Autonomous System Boundary Router, AS Boundary Router structural representation among the present invention.

Fig. 5 is the flow chart of route issue embodiment among the present invention.

Fig. 6 is the route issuing process schematic diagram in the specific embodiment of the invention one.

Fig. 7 is the route issuing process schematic diagram in the specific embodiment of the invention two.

Embodiment

For making purpose of the present invention, technical scheme and advantage clearer, the embodiment that develops simultaneously with reference to the accompanying drawings is described in further detail the present invention.

In cross-domain B, when the VPN-instance on the PE adopts the label distribution mode of Per-instance, routing tag from same VPN-instance is identical, at this moment, ASBR there is no need to be every new distributing labels of route, and at from same VPN-instance and the identical route of outgoing label, ASBR can only distribute a label, and only generate an ILM, do not influence normal data forwarding like this.

When ASBR will issue a route, and next jumping of this route is changed, and in the time of must changing label in this locality, ASBR redistributes a label for this route, also is to use the label identical with other route, and this need make a strategic decision on ASBR.

The basic thought of route issuing method provided by the invention is: ASBR is in issue during route, for the route assignment that next is jumped, outgoing label is identical respectively received identical go into label, and described route is released.

At route issuing method provided by the present invention, the present invention also provides a kind of Autonomous System Boundary Router, AS Boundary Router, referring to shown in Figure 4, this router comprises: input unit, label distribution unit and output unit, wherein, input unit is used to receive route, and the route of receiving is sent to the label distribution unit; The label distribution unit be used to the route assignment that next is jumped, outgoing label is identical respectively received identical go into label, and this route is sent to output unit; The route that output unit is used for receiving releases.

Wherein, described route issuing process specifically comprises: after ASBR receives route, search local routing table, the also identical issue route of outgoing label that judges whether to exist next to jump and outgoing label identical and receive route with next jumping of receiving route, if exist, that then this has been issued route goes into label as the label of going into of receiving route, and the route of receiving is released; If there is no, then redistribute one and go into label, and according to the outgoing label of receiving route and be the label of going into of this route assignment, generates a label exchange and shine upon the ILM list item, then the route of receiving is released for the route received.Certainly, here for the route received redistribute go into label should with issue route to go into label inequality.Corresponding Autonomous System Boundary Router, AS Boundary Router shown in Figure 4, wherein, described search and the process of distributing labels can be finished by the label distribution unit.

In addition, ASBR can also set up one and comprise next data structure and preservation of jumping Nexthop, outgoing label OutLabel and going into label InLabel of issuing route, such as, this data structure is called NextHopLabel entry, abbreviating NHL_entry as, is key assignments with Nexthop and OutLabel.Like this, ASBR can handle according to flow process shown in Figure 5 when the issue route, mainly may further comprise the steps:

After step 501:ASBR receives route, next jumping and outgoing label according to this route are searched the NHL_entry tabulation, whether next jumping and the outgoing label of judging this route have been included in the NHL_entry tabulation, that is to say, in NHL_entry tabulation, search and whether exist next that receive route with this to jump and outgoing label is corresponding goes into label, if exist, then execution in step 502; Otherwise, execution in step 503.

Step 502:ASBR with among the NHL_entry with receive route next jump and outgoing label is corresponding goes into label, as the label of going into of receiving route, and execution in step 504.

Step 503:ASBR is that the route of receiving is redistributed into label.

Simultaneously, it is the label of going into of this route assignment that ASBR reaches according to the outgoing label of receiving route, generate a label exchange mapping ILM list item, and create a NHL_entry, use this to receive next jumping, the outgoing label of route and go into label to be each the element assignment among the NHL_entry.

Certainly, here for the route received redistribute go into label should with adopt that the NHL_entry form preserves to go into label inequality.

Step 504:ASBR releases the route of receiving.

Corresponding Autonomous System Boundary Router, AS Boundary Router shown in Figure 4, wherein, step 501 is described searches and step 502,503 can be finished by the label distribution unit, and step 504 is finished by output unit.

For ease of understanding,, the route issuing method among the present invention is described in detail below with reference to two specific embodiments.

Embodiment one, ASBR receive the situation of the route of a plurality of VPN from a PE

Referring to shown in Figure 6, ASBR1 only links to each other with PE1, and two VPN-instance:VPN1 of the last configuration of PE1 and VPN2 all adopt the label distribution mode of Per-instance.

The RD of VPN1 is 100:1, suppose to have three route: 10.1.0.0/16,10.2.0.0/16,10.3.0.0/16, owing to adopt the label distribution mode of Per-instance, therefore, these routes with the form of VPN-IPv4 route when ASBR1 issues, all use identical label Lm.

The RD of VPN2 is 100:2, and same hypothesis has three route: 10.1.0.0/16,10.2.0.0/16,10.3.0.0/16, supposes that here there are address overlap in VPN1 and VPN2, and certainly, the address of VPN1 and VPN2 also can be different.In like manner owing to adopt the label distribution mode of Per-instance, these routes with the form of VPN-IPv4 route when ASBR1 issues, all use identical label Ln.

Wherein, Lm is not equal to Ln, because PE1 can not distribute identical label for different VPN-instance.

ASBR1 is as follows from the situation of the VPN-IPv4 route that PE1 receives: RD is that the route of 100:1 has three, is respectively 10.1.0.0/16,10.2.0.0/16,10.3.0.0/16, and next jumping is PE1, and outgoing label is Lm; RD is that the route of 100:2 also has three, is respectively 10.1.0.0/16,10.2.0.0/16,10.3.0.0/16, and next jumping is PE1, and outgoing label is Ln.

When ASBR1 issues these routes to ASBR2, can be that three route 10.1.0.0/16,10.2.0.0/16, the 10.3.0.0/16 of Lm distributes the identical label Lj that goes into for outgoing label, and generate an ILM list item (InLabel/OutLabel:Lj/Lm); For outgoing label is that three route 10.1.0.0/16,10.2.0.0/16, the 10.3.0.0/16 of Ln distributes the identical label Lk that goes into, and generate an ILM list item (InLabel/OutLabel:Lk/Ln).Wherein, Lj is not equal to Lk.

ASBR2 is as follows from the situation of the VPN-IPv4 route that ASBR1 receives: RD is that the route of 100:1 has three, is respectively 10.1.0.0/16,10.2.0.0/16,10.3.0.0/16, and next jumping is ASBR1, and outgoing label is Lj; RD is that the route of 100:2 also has three, is respectively 10.1.0.0/16,10.2.0.0/16,10.3.0.0/16, and next jumping is ASBR1, and outgoing label is Lk.

When ASBR2 issues these routes to PE2, can be that three route 10.1.0.0/16,10.2.0.0/16, the 10.3.0.0/16 of Lj distributes the identical label Lx that goes into for outgoing label, and generate an ILM list item (InLabel/OutLabel:Lx/Lj); For outgoing label is that three route 10.1.0.0/16,10.2.0.0/16, the 10.3.0.0/16 of Lk distributes the identical label Ly that goes into, and generate an ILM list item (InLabel/OutLabel:Ly/Lk).Wherein, Lx is not equal to Ly.

PE2 is as follows from the situation of the VPN-IPv4 route that ASBR2 receives: RD is that the route of 100:1 has three, is respectively 10.1.0.0/16,10.2.0.0/16,10.3.0.0/16, and next jumping is ASBR2, and outgoing label is Lx; RD is that the route of 100:2 has three, is respectively 10.1.0.0/16,10.2.0.0/16,10.3.0.0/16, and next jumping is ASBR2, and outgoing label is Ly.

When transmitting, suppose that CE3 has data will be forwarded to CE1, destination address is 10.1.1.1.After PE2 receives the IP message that CE3 sends, search forwarding information base (FIB) table of VPN1, obtain corresponding route 10.1.0.0/16, outgoing label is Lx, and PE2 stamps vpn label Lx for the IP message, sends to ASBR2 by PE2 to the tunnel of ASBR2; After ASBR2 receives the MPLS message, according to vpn label Lx, find corresponding ILM list item (InLabel/OutLabel:Lx/Lj), carry out the label exchange, vpn label becomes Lj, then the MPLS message behind the switch label is sent to ASBR1; After ASBR1 receives the MPLS message that ASBR2 sends, according to vpn label Lj, find corresponding ILM list item (InLabel/OutLabel:Lj/Lm), carry out the label exchange, vpn label becomes Lm, then the MPLS message behind the switch label is sent to PE1 by ASBR1 to the tunnel of PE1; After PE1 receives the MPLS message that ASBR1 sends, eject vpn label Lm, search the fib table of the VPN1 example of Lm correspondence, success is transmitted to CE1 to the IP message.

As seen, for the route from same PE, ASBR is can be for the route assignment with identical outgoing label identical goes into label.Because for the VPN-IPv4 route of only receiving from a PE, on behalf of them, different outgoing label just necessarily come from different VPN-instance, difference according to outgoing label, these routes can be divided into different set, route with identical outgoing label belongs to same set, route in the same set can be assigned with the identical label of going into, and is distributed to the ASBR of opposite end.

Embodiment two, ASBR receive the situation of the route of a plurality of VPN from a plurality of PE

Referring to shown in Figure 7, ASBR1 links to each other with PE3 with PE1 respectively, respectively disposes two VPN-instance:VPN1 and VPN2 on PE1 and the PE3, all adopts the label distribution mode of Per-instance.

The RD of the last VPN1 of PE1 is 100:1, suppose to have three route: 10.1.0.0/16,10.2.0.0/16,10.3.0.0/16, owing to adopt the label distribution mode of Per-instance, therefore, these routes with the form of VPN-IPv4 route when ASBR1 issues, all use identical label Lm.The RD of VPN2 is 100:2, and same hypothesis has three route: 10.1.0.0/16,10.2.0.0/16,10.3.0.0/16, these routes with the form of VPN-IPv4 route when ASBR1 issues, all use identical label Ln.Here suppose still that there are address overlap in VPN1 and VPN2, certainly, the address of VPN1 and VPN2 also can be different.

The RD of the last VPN1 of PE3 is 100:1, supposes to have three route: 20.1.0.0/16,20.2.0.0/16,20.3.0.0/16, these routes with the form of VPN-IPv4 route when ASBR1 issues, all use identical label Lm.The RD of VPN2 is 100:2, and same hypothesis has three route: 20.1.0.0/16,20.2.0.0/16,20.3.0.0/16, these routes with the form of VPN-IPv4 route when ASBR1 issues, all use identical label Ln.

Here, the label of the last VPN1 route assignment of PE1 is identical with the label that PE3 goes up the VPN1 route assignment, the label of the last VPN2 route assignment of PE1 is identical with the label that PE3 goes up the VPN2 route assignment, because on different PE, for the VPN-instance distributed labels may be identical.Certainly, also can distribute different labels respectively.

ASBR1 is as follows from the situation of the VPN-IPv4 route that PE1 receives: RD is that the route of 100:1 has three, is respectively 10.1.0.0/16,10.2.0.0/16,10.3.0.0/16, and next jumping is PE1, and outgoing label is Lm; RD is that the route of 100:2 also has three, is respectively 10.1.0.0/16,10.2.0.0/16,10.3.0.0/16, and next jumping is PE1, and outgoing label is Ln.

ASBR1 is as follows from the situation of the VPN-IPv4 route that PE3 receives: RD is that the route of 100:1 has three, is respectively 20.1.0.0/16,20.2.0.0/16,20.3.0.0/16, and next jumping is PE3, and outgoing label is Lm; RD is that the route of 100:2 also has three, is respectively 20.1.0.0/16,20.2.0.0/16,20.3.0.0/16, and next jumping is PE3, and outgoing label is Ln.

That is to say, on ASBR1, be in the routing table of 100:1 at RD, and it all is Lm that the outgoing label of 6 routes is arranged, and is respectively: 10.1.0.0/16,10.2.0.0/16,10.3.0.0/16,20.1.0.0/16,20.2.0.0/16,20.3.0.0/16.At RD is in the routing table of 100:2, and it all is Ln that the outgoing label of 6 routes is also arranged, and is respectively: 10.1.0.0/16,10.2.0.0/16,10.3.0.0/16,20.1.0.0/16,20.2.0.0/16,20.3.0.0/16.

At this moment, when ASBR1 issues these routes to ASBR2, just can not be only according to the identical label that determines that issue is identical of outgoing label.If to outgoing label is that 6 routes of Lm are all used same label Lj, generate an ILM list item (InLabel/OutLabel:Lj/Lm) simultaneously, so when VPN traffics when ASBR2 forwards, vpn label will be Lj, with being forwarded to correct PE after the Lm exchange.

Therefore, ASBR1 must consider next jumping of VPN-IPv4 route simultaneously, for the route from same next jumping, if outgoing label is identical, can use the identical label of going into; For route,, can not use the identical label of going into even outgoing label is identical from different next jumping.

As shown in Figure 6, when ASBR1 issues these routes to ASBR2, can be for outgoing label be Lm, next jump for three route 10.1.0.0/16, the 10.2.0.0/16 of PE1,10.3.0.0/16 distribution identical go into label Lj, and generate an ILM list item (InLabel/OutLabel:Lj/Lm); For outgoing label is Ln, next jump for three route 10.1.0.0/16, the 10.2.0.0/16 of PE1,10.3.0.0/16 distribution identical go into label Lk, and generate an ILM list item (InLabel/OutLabel:Lk/Ln); For outgoing label is Lm, next jump for three route 20.1.0.0/16, the 20.2.0.0/16 of PE3,20.3.0.0/16 distribution identical go into label Lx, and generate an ILM list item (InLabel/OutLabel:Lx/Lm); For outgoing label is Ln, next jump for three route 10.1.0.0/16, the 10.2.0.0/16 of PE3,10.3.0.0/16 distribution identical go into label Ly, and generate an ILM list item (InLabel/OutLabel:Ly/Ln).Wherein, Lj, Lk, Lx, Ly are different.

The VPN-IPv4 route that ASBR2 will receive from ASBR1 is when PE2 transmits, for outgoing label is that three route 10.1.0.0/16,10.2.0.0/16, the 10.3.0.0/16 of Lj distributes the identical label La that goes into, and generate an ILM list item (InLabel/OutLabel:La/Lj); For outgoing label is that three route 10.1.0.0/16,10.2.0.0/16, the 10.3.0.0/16 of Lk distributes the identical label Lb that goes into, and generate an ILM list item (InLabel/OutLabel:Lb/Lk); For outgoing label is that three route 20.1.0.0/16,20.2.0.0/16, the 20.3.0.0/16 of Lx distributes the identical label Lc that goes into, and generate an ILM list item (InLabel/OutLabel:Lc/Lx); For outgoing label is that three route 20.1.0.0/16,20.2.0.0/16, the 20.3.0.0/16 of Ly distributes the identical label Ld that goes into, and generate an ILM list item (InLabel/OutLabel:Ld/Ly).Wherein, La, Lb, Lc, Ld are different.

As seen,, can not only distribute the identical label of going into, have only when outgoing label and next and jump homogeneous phase simultaneously, could distribute the identical label of going into according to identical just decision of outgoing label for the VPN-IPv4 route of receiving from a plurality of PE.That is to say, for route from different PE, ASBR be have the route assignment of identical outgoing label and identical next jumping identical go into label.

The above has carried out further detailed description to purpose of the present invention, technical scheme and beneficial effect; institute is understood that; the above is not in order to restriction the present invention; within the spirit and principles in the present invention all; any modification of being made, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (10)

1, the Autonomous System Boundary Router, AS Boundary Router route issuing method is characterized in that, this method comprises: Autonomous System Boundary Router, AS Boundary Router ASBR be the route assignment that next is jumped, outgoing label is identical respectively received identical go into label, and described route is released.

2, method according to claim 1 is characterized in that, described distribution comprises:

After A1, ASBR receive route, judge whether to exist and the issue route that next is jumped, outgoing label is identical respectively of this route, if exist, execution in step B1 then, otherwise, execution in step C1;

B1, go into label as the label of going into of receiving route, and the route of receiving is released the processing of process ends what this had issued route;

C1, go into label for the route assignment received, and the route of receiving is released.

3, method according to claim 2 is characterized in that, described step C1 further comprises:

ASBR is according to the described outgoing label of receiving route and be the label of going into of this route assignment, generates label exchange mapping ILM list item.

4, method according to claim 2 is characterized in that, step C1 described for the route assignment received go into label and step B1 described issued route to go into label different.

5, method according to claim 1 is characterized in that, ASBR sets up and comprises next jumping, the outgoing label of issuing route and the data structure of going into label and preservation, and described distribution comprises:

After A2, ASBR received route, next that judge this route jumped and whether outgoing label has been included in the described data structure, if, execution in step B2 then, otherwise, execution in step C2;

B2, ASBR with in the described data structure with receive that next jumping of route and outgoing label are corresponding and go into label, as the label of going into of receiving route, and the route of receiving released;

C2, ASBR are that the route assignment of receiving is gone into label, and the route of receiving is released.

6, method according to claim 5 is characterized in that, described step C2 further comprises:

ASBR is according to the described outgoing label of receiving route and be the label of going into of this route assignment, generates label exchange mapping ILM list item; And receive next jumping, the outgoing label of route and go into label and preserve with described data structure form with described.

7, method according to claim 5 is characterized in that, step C2 described for the route assignment received go into label with adopt described data structure form preservation to go into label different.

8, method according to claim 1 is characterized in that, described distribution comprises:

For route from same service provider edge router PE, ASBR be have the route assignment of identical outgoing label identical go into label;

For route from different PE, ASBR be have the route assignment of identical outgoing label and identical next jumping identical go into label.

According to each described method of claim 1 to 8, it is characterized in that 9, described route is the 4th edition VPN-IPv4 route of Virtual Private Network-Internet Protocol.

10, a kind of Autonomous System Boundary Router, AS Boundary Router is characterized in that, this router comprises: input unit, label distribution unit and output unit, wherein,

Input unit is used to receive route, and the route of receiving is sent to the label distribution unit;

The label distribution unit be used to the route assignment that next is jumped, outgoing label is identical respectively received identical go into label, and this route is sent to output unit;

The route that output unit is used for receiving releases.

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