CN102075419B

CN102075419B - Method for generating and transmitting three-layer virtual special network equative routing and edge router

Info

Publication number: CN102075419B
Application number: CN201010621704.2A
Authority: CN
Inventors: 赵昌峰; 王茹萍
Original assignee: Hangzhou H3C Technologies Co Ltd
Current assignee: New H3C Technologies Co Ltd
Priority date: 2010-12-27
Filing date: 2010-12-27
Publication date: 2014-06-18
Anticipated expiration: 2030-12-27
Also published as: CN102075419A

Abstract

The invention provides a method for generating and transmitting three-layer virtual special network equative routing and a provider edge router (PE). The equative routing generating method comprises the following steps that: A, routing received from the downstream PE is stored by the PE, equative routing is preferably selected, and the preferably selected routing is added with equative routing identification attributes and are activated; and B, when upstream equipment is the PE, the equative routing added with the equative routing identification attributes are issued to the upstream PE. The equative transmitting method and the PE are both realized on the basis of the method, and the utilization rate of link bandwidth is increased.

Description

The generation of Layer3 Virtual Private Network equal-cost route and retransmission method and edge router

Technical field

The present invention relates to communication technical field, relate in particular to a kind of generation and retransmission method and edge router of Layer3 Virtual Private Network equal-cost route.

Background technology

Multiprotocol label switching (mpls) Layer3 Virtual Private Network (L3VPN) is a kind of L3VPN technology based on Provider Edge (PE) in service provider's vpn solution, it uses Border Gateway Protocol (BGP) on service provider backbone, to issue VPN route, uses MPLS on service provider backbone, to forward VPN message.MPLS L3VPN extensive use in operator at present, for client provides VPN service.

MPLS L3VPN model is made up of three parts: the P (P) in customer network edge (CE), Provider Edge (PE) and service provider network.

CE equipment, has interface to be directly connected with service provider (SP).CE can be router or switch, can be also a main frame.CE " perception ", less than the existence of VPN, does not need to support MPLS yet.

Pe router, is the edge device of service provider network, is directly connected with user's CE.In MPLS network, all processing of VPN are all occurred on PE.

P router, the P in service provider network, is not directly connected with CE.P device just will possess basic MPLS transfer capability.

In basic MPLS L3VPN application, do not comprise cross-domain situation, VPN message repeating adopts two-layer label mode:

Ground floor label, outer layer label exchanges in backbone network inside, the strip label switching path (LSP) of indication from PE to opposite end PE.VPN message utilizes this layer of label, can arrive opposite end PE along LSP;

Second layer label, vpn label, using in the time that opposite end PE arrives CE, is indicated message should be sent to which website (Site), or more specifically, is arrived which CE.Like this, opposite end PE can find the interface E-Packeting according to vpn label.

In particular cases, two Site that belong to same VPN are connected to same PE, only need to know how to arrive opposite end CE in this case.

Referring to Fig. 1, Fig. 1 is existing MPLS L3VPN networking schematic diagram.Take Fig. 1 as example, the study of VPN route and the forwarding of message are described, now MPLS L3VPN networking configuration completes.

The study of VPN route:

1, Site2 is by local routing 1.1.1.2, i.e. VPN route, is distributed to CE2;

2, CE2 sends to PE2 by this route after receiving, down hop is oneself;

3, PE2 receives this route, finds the private network of this route from oneself, and this route is joined to the interim optimum chained list in VPNv4 routing table, optimizes an optimum route, and VPNv4 routing table sends to PE2 by bgp neighbor by optimum route.According to VPN instance configuration route-distinguisher (RD) and the route target (RT) of the binding of private network interface, in the time sending this route, add this two attributes;

4, suppose that PE1, two P, PE2 belong to same autonomous system (AS) territory, on P, need to enable reflection function, this route is reflected, do not change route next jump;

5, after PE1 receives this VPN route, optimize an optimum route, the optimum route optimizing is activated, iterates to public network tunnel.According to the RT attribute of VPN route, this route is inserted to VPN routing table the inside, and issue this route to CE1, down hop is oneself;

6, after CE1 receives this route, this route is distributed to Site1; The route of Site2 has just passed to Site1 above like this, has just had corresponding route table items on Site1.

The forwarding of VPN message:

1, Site1 sends the IP message that a destination address is 1.1.1.2, by CE1, message is sent to PE1;

2, PE1 arrives according to message interface and destination address are searched VPN instance list item, after coupling, in public network tunnel, forward the packet away, stamp internal layer and outer two labels simultaneously;

3, the outer layer label of MPLS network utilisation message, is sent to PE2 by message, and message has been stripped from outer layer label in the time arriving PE2 previous dive, only containing vpn label.

4, PE2 searches VPN instance list item according to vpn label and destination address, determines the outgoing interface of message, forwards the packet to CE2.

5, CE2 is sent to destination according to normal IP repeating process by message.

Referring to Fig. 2, Fig. 2 is existing CE dual-homing networking schematic diagram.CE1 is connected with PEA, PEB respectively, guarantees link redundancy backup.When after link failure between CE1 and PEA, CE1 sends fault message to PEC, and PEC reselects route, and reflection is to PED, and flow will be switched on the link between CE2 and PEB.

In existing realization, at PEA and PEB, route is sent to after PEC, PEC utilizes preference rule to optimize a route from these two routes, preference rule is wherein, PEC leaves the route of receiving in an interim optimum chained list in, according to BGP rule, by do not meet extracing of rule from interim optimum chained list, until optimize a legal optimum route.Using the route optimizing as optimum route, reflect optimum route by bgp neighbor to PED, utilize same preference rule to optimize an optimum route, and the optimum route optimizing is activated, iterate to public network tunnel, at this moment on PED, only can have a route, the CE1 route next jump that PED receives so or be PEA, for PEB, cannot carry out equivalence and forward.

Summary of the invention

The invention provides a kind of generation method of Layer3 Virtual Private Network equal-cost route, improved the utilance of link bandwidth.The method comprises:

A, provider edge PE preserve the route receiving from downstream PE, and the row equivalent routing optimization of going forward side by side, for the equal-cost route optimizing increases equal-cost route identity property and activates;

B, be PE for upstream equipment, increased the equal-cost route of equal-cost route identity property and send to upstream PE optimizing.

Wherein, described equal-cost route identity property, comprises the equal-cost route identification number ECMP ID for distinguishing equal-cost route; The described method that increases equal-cost route identity property for the equal-cost route that optimizes is: for equal-cost route corresponding to same prefix distributes different ECMP ID.

Described equal-cost route method for optimizing is: in the interim optimum chained list in VPNv4 routing table, preferably have the maximum route of route, the Preferred-value value in public network tunnel, route that local first level is the highest, polymerization route, the route of AS shortest path, the minimum route of route, med value that ORIGIN type level is high; According to the route of coming to the selective sequential of IBGP from EBGP, alliance; In the time that the route number optimizing is less than or equal to default maximum equal-cost route number, preferably complete, in the time that the route number optimizing exceedes default maximum equal-cost route number, get at random the route of default maximum equal-cost route number as equal-cost route number;

Or, in interim optimum chained list in VPNv4 routing table, preferably have the route of the maximum route of route, the Preferred-value value in public network tunnel, route that local first level is the highest, polymerization route, AS shortest path, route that route, med value that ORIGIN type level is high are minimum, according to the route of coming to the selective sequential of IBGP from EBGP, alliance the preferred minimum route of down hop public network route Cost value; In the time that the route number optimizing is less than or equal to default maximum equal-cost route number, preferably complete, in the time that the route number optimizing exceedes default maximum equal-cost route number, get at random the route of default maximum equal-cost route number as equal-cost route number.

The method further comprises: in the time that needs send renewal route to neighbours, if sent the route of upgrading therewith the same prefix of route before, and this renewal route is equal-cost route, for increasing equal-cost route identity property in preferred condition without the route of equal-cost route identity property with the same prefix of this renewal route, if this renewal route is non-equivalence route, will remove with the equal-cost route identity property of the route in not preferred state of the same prefix of this renewal route; If do not send the route of upgrading therewith the same prefix of route before, and this renewal route is equal-cost route, is this route assignment equal-cost route identity property; The equal-cost route of the same prefix that has equal-cost route identity property is sent to upstream PE.

Described send to upgrade when route to neighbours be: re-start routing optimization, preferably route change, neighbor state change trigger routing update, configuration variation triggers routing update, or triggers routing update when neighbours' refresh requests.

The method further comprises: if when abnormal conditions appear in ECMP ID in the attribute-bit of the renewal route sending, only retain this route; If receive with described ECMP ID and occur that the route of abnormal conditions has the route of identical RD and prefix, this route is override to the route of all identical RD with it and prefix before.

The method that in described steps A, PE preserves the route receiving from downstream PE is: the route of receiving is left in transit shed, search in the interim optimum chained list in VPNv4 routing table according to the prefix of route and Route Distinguisher RD attribute, the route of the corresponding prefix of if there is no receiving, leaves the described route of receiving in local VPNv4 routing table; If there is the route of the corresponding prefix received, and described in the route received be equal-cost route, determine that according to the equivalent marking attribute of route route stores local VPNv4 routing table or renewal into.

Described equal-cost route identity property further comprises: for representing the action identification OPT of routing update state;

The described method that increases equal-cost route identity property for the equal-cost route that optimizes further comprises: by route corresponding same prefix, the OPT of the route that will upgrade is at first designated Article 1 equal-cost route, and route OPT that will final updating is designated the last item equal-cost route;

The method that the route of determining the described equivalent marking attribute according to route stores local routing table or renewal into is: if in the equal-cost route of receiving, in equivalent marking attribute, OPT is also non-the last item equal-cost route of non-Article 1 equal-cost route, and with the ECMP ID of local all same prefix is unequal, the described equal-cost route of receiving is saved in local VPNv4 table;

If in the equal-cost route of receiving, OPT position is shown as Article 1 equal-cost route, the all routes that are this prefix in local VPNv4 routing table are added update mark, start to upgrade, the update mark of the route of upgrading is deleted, until receive that OPT is shown as the last item equal-cost route, this time upgrade and finish, and the route that has update mark is deleted.

The present invention also provides a kind of Layer3 Virtual Private Network the method forwarding of equal value, has improved the utilance of link bandwidth, and the equivalence that has realized message forwards.The method comprises:

B, be PE for upstream equipment, increased the equal-cost route of equal-cost route identity property and send to upstream PE optimizing; Be CE for upstream equipment, by optimizing the equal-cost route that has increased equal-cost route identity property, iterate to public network tunnel;

C, PE receive the message that CE sends, and send to target CE with described public network tunnel.

Wherein, in described step C, PE further comprises after receiving the message that CE sends: under by flow forwarding pattern, determine a paths by HASH algorithm, the message of receiving is sent to target CE by this path.

The present invention also provides the PE in a kind of Layer3 Virtual Private Network, has improved the utilance of link bandwidth.This PE comprises:

Described route receiver module, for receiving the route sent from downstream PE, preserving and send to described equal-cost route preferred module;

Described equal-cost route preferred module, is connected with described route receiver module, carries out equivalence preferably for the route that described route receiver module is received, and the equal-cost route optimizing sends to described equal-cost route identity property to increase module; Described equal-cost route identity property increases module, is connected with described equal-cost route preferred module, increases equal-cost route identity property for the equal-cost route that described equal-cost route preferred module is optimized;

Described equal-cost route sending module, increases module with described equal-cost route identity property and is connected, and the equal-cost route that increases equal-cost route identity property is sent to upstream PE;

Described equal-cost route iteration module, increases module with described equal-cost route identity property and is connected, and the equal-cost route that increases equal-cost route identity property is activated and iterate to public network tunnel.

Wherein, described equal-cost route identity property increases module and further comprises: route judge module, described route judge module is used for judging after routing optimization, neighbor state changes or configuration variation, whether trigger the renewal of route, if, send to described equal-cost route identity property to increase module described route, otherwise described route is sent to described equal-cost route sending module or described equal-cost route iteration module.

From above technical scheme, this programme optimizes equal-cost route on PE, increases equal-cost route identity property iterate to public network tunnel by the equal-cost route to optimizing, and the equivalence that realizes message by public network tunnel forwards, and has improved the utilance of link bandwidth.

Accompanying drawing explanation

Fig. 1 is existing MPLS L3VPN networking schematic diagram;

Fig. 2 is existing CE dual-homing networking schematic diagram;

Fig. 3 is the L3VPN of the present invention networking schematic diagram that forwards of equal value;

Fig. 4 is equivalent marking attribute format schematic diagram of the present invention;

Fig. 5 is the PEC process flow figure of equal-cost route generation method of the present invention;

Fig. 6 is the PED process flow figure of equal-cost route generation method of the present invention;

Fig. 7 is the PE structural representation in L3VPN of the present invention.

Embodiment

For making object of the present invention, technological means and advantage clearer, below in conjunction with drawings and the specific embodiments, the present invention is further detailed explanation.

Basic thought of the present invention is that PE preserves the route receiving from downstream PE, and the row equivalent routing optimization of going forward side by side, for the equal-cost route optimizing increases equal-cost route identity property and activates; Be PE for upstream equipment, increased the equal-cost route of equal-cost route identity property and send to upstream PE optimizing.The retransmission method of equal value of message and PE all realize based on above-mentioned thought, have improved the utilance of link bandwidth.

On PE equipment, configure equivalent route selection algorithm, below all claim that this algorithm is equal-cost route preference rule.

When enabling after VPNv4 route ability of equal value, VPNv4 routing optimization is carried out preferably as follows:

1, be first discarded into down hop (NEXT_HOP) and there is no the route in public network tunnel;

2, the maximum route of preferred value (Preferred-value), route maximum Preferred-value value is added to interim optimum chained list, while there is multiple identical maximum, corresponding route all adds interim optimum chained list, and wherein interim optimum chained list is present in VPNv4 routing table;

3, the preferred the highest route of local first level (LOCAL_PREF), is not the highest route by local first level, from interim optimum chained list, removes;

4, preferred polymeric route by the route that is not polymerization route, is removed from interim optimum chained list;

5, the shortest route in preferred AS path (AS_PATH) by the long route of AS_PATH, is removed from interim optimum chained list;

6, selecting successively ORIGIN type is the route of IGP, EGP, Incomplete, will not have preferred route to remove from interim optimum chained list, in ORIGIN type, there is no the preferred EGP of IGP, there is no the preferred Incomplete of EGP;

7, preferably Multi-Exit Discriminator attribute (MED) is worth minimum route, and route large med value is removed from interim optimum chained list;

8, select successively to learn from External BGP (EBGP), alliance, Internal BGP (IBGP) the route of coming;

If now have many routes in interim optimum chained list and do not exceed default maximum equal-cost route number, preferably complete, if now exceed default maximum equal-cost route number, get at random the route of default maximum equal-cost route number as equal-cost route.Wherein default maximum equal-cost route number user or operator can be configured in advance according to practical situations.

Through above-mentioned preferably after, in interim optimum chained list, route is optimum route, if there are many, forms VPNv4 route of equal value.

In actual applications, it is preferred that user or operator can determine whether after the 8th step, increase by the 9th step as the case may be, and the 9th step method for optimizing is as follows: the preferably minimum route of down hop public network route Cost value, if the identical equivalence that forms of Cost; If down hop public network route Cost is ignored in configuration, the route that down hop Cost is different also can form equivalence; The route that is different agreement to down hop public network route, does not compare Cost, thinks identical; From interim optimum chained list, extract and cannot form route of equal value with optimum link.

Preferred VPNv4 route is put into the routing table of corresponding VPN, in VPN routing table, preferably, can in VPN routing table, be formed equivalence with the route of different RD, the condition of equivalence is to have identical local first level, AS_PATH, MED and Origin attribute.

The in the situation that of route reflection, when VPNv4 route exists many preferred routes of equivalence on reflector, should reflect these preferred routes.For realizing this ability, newly-increased a kind of attribute, is called equivalent marking attribute.This is a kind of optional non-transitive attribute.Referring to Fig. 4, Fig. 4 is the form of this equivalent marking attribute.

In Fig. 4, identifier (Flag) is 0x00, and identifying this attribute is a kind of optional non-transitivity attribute; Equal-cost route type (ECMPT), as the case may be, composes a specific value, represents that this attribute is equivalent marking attribute; Loaded length is 4, the byte number occupying altogether for OPT and ECMP ID; OPT, represents the routing update action identification of this ECMPT, and highest order is Start position, effectively time, represents the route that Article 1 will be upgraded, and second high position be End position, when effective, and the route that expression the last item will upgrade.Equal-cost route identification number (ECMP ID) is signless integer, 2 bytes.ECMP ID is 0 o'clock, represents this Route error, is abnormal conditions, retains this route, if receive before the route of identical RD and same prefix, this route overrides the route of all identical RD and same prefix; Other effective values represent the numbering of this route in same prefix.

It is inner that this attribute appears at path attribute in UPDATA message (Path Attributes), and this attribute is only meaningful between two neighbours, can not forward this attribute to other neighbours.For the equipment of this attribute of nonrecognition, this attribute can be left in the basket, and route learning is unaffected.

In router, be that each preferred concrete equal-cost route distributes an equivalent marking attribute, equal-cost route corresponding to same prefix all distributes different ECMP ID, for distinguishing equal-cost route.When concrete enforcement, these ECMP ID scopes can be from 1 to default maximum equal-cost route number, in the equivalent marking attribute of ECMP ID minimum, OPT Start position 1 represents effectively, represent that this route is the route that Article 1 will be upgraded, in the maximum equivalent marking attribute of ECMP ID, OPT End position 0 represents effectively, represent that this route is the route that the last item will upgrade, OPT position 00 in other equivalent marking attributes.User can arrange concrete numeric representation related sense according to actual service condition.All think in an embodiment of the present invention OPT End position and OPT Start position 1 are represented effectively, set to 0 expression invalid.

Below, the specific embodiment of the invention is elaborated.

Referring to Fig. 3, Fig. 3 is the L3VPN networking schematic diagram that forwards of equal value.CE1 is connected with PEB with PEA respectively, and PEA is connected with PEC respectively with PEB, and PEC is connected by P with PED, and PED is connected with CE3 with CE2 respectively.

In Fig. 3, introduce the transmitting terminal processing of route as an example of PEC example, introduce the processing of route receiving terminal as an example of PED example.

The route that PEC reception downstream PE A and PEB send, the route of receiving is stored in VPNv4 routing table in interim optimum route chained list, selects equal-cost route by preference rule, wherein, described in method, the process of preference rule selection equal-cost route sees above, repeat no more.

Referring to Fig. 5, Fig. 5 is the PEC process flow figure of equal-cost route generation method of the present invention.Concrete steps are as follows:

Whether step 501, in the time that needs send renewal route to neighbours, sent the route of the same prefix of route therewith before judgement, if not, and execution step 502; If so, execution step 503;

Re-start preferred route, preferably route changes, and neighbor state changes, configuration variation or neighbours' refresh requests, while having triggered the renewal of route, sends renewal route to neighbours.

Step 502, if this renewal route is equal-cost route, it is this renewal route assignment equal-cost route identity property, and be 1 by OPT Start position in the attribute of equal value of ECMP ID minimum, the equivalent marking attribute OPT End position of ECMP ID maximum is 1, the OPT of other ECMP ID route is set to 00, continues execution step 506; If this renewal route is not equal-cost route, by existing mode processing.

For each route is according to ECMP ID order-assigned equivalent marking attribute from small to large, the method that ECMP ID distributes is for to distribute successively since 1.Here inventor illustrates with a kind of situation of concrete practical application, and ECMP ID also can be according to from big to small or other order assignment, and beginning and the end of routing update also can be gone to set according to user custom in OPT Start position and OPT End position.The choice and operation of following three parameters is the better implementation of one that inventor thinks.

Step 503, if this renewal route is equal-cost route, judges that these upgrade route and whether had before distributed equivalent marking attribute, and if so, execution step 505, if not, performs step 504; If this renewal route is non-equivalence route, will remove with the equivalent marking attribute of the route in not preferred state of the same prefix of this route.

Step 504, for increasing equivalent marking attribute in preferred condition without the route of equal-cost route identity property with the same prefix of this route, continues execution step 505.

When increasing equivalent marking attribute assignment ECMP ID, this ECMP ID is not used in this prefix

Step 505, the equivalent marking attribute OPT End position that is 1, ECMP ID maximum for OPT Start position in the attribute of equal value of ECMP ID minimum is 1, the OPT of other route is set to 00.

Above-mentioned when telling about certain route and occurring to upgrade, the response processing of carrying out, if when many routing updates, can process according to above-mentioned the same method.

Step 506, is put into equal-cost route to send on chained list by route according to ECMP ID order from small to large.

The preferred embodiment that the method is only lifted for the present invention, in practical application, can be put into and send on chained list according to the assignment order of ECMP ID.

Step 507, BGP sets up People Near Me, when transmission, the route of different ECMP ID is carried out to message assembling, the equal-cost route identity property of every route is bundled in message simultaneously, sends to PED.

When equal-cost route in VPNv4 routing table is put into transmission chained list, equal-cost route in VPNv4 table is put into the routing table of corresponding VPN, preferred in VPN routing table, can in VPN routing table, form of equal value with the route of different RD, the condition of equivalence is to have identical local first level, AS_PATH, MED and Origin attribute.On this PE, if the equal-cost route optimizing is the route in VPNv4 table, to receive after message, the public network tunnel forming by the present invention E-Packets, otherwise by existing techniques in realizing message repeating.

Referring to Fig. 6, Fig. 6 is the PED process flow figure of equal-cost route generation method of the present invention.Concrete steps are as follows:

Step 601, PED receives the message that carries route, and the attribute of route is resolved, and by attribute, the route of receiving is saved in to transit shed.

The attribute of resolving comprises equivalent marking attribute.

Step 602 searches whether there is the route of receiving corresponding prefix according to the prefix of route and RD attribute in interim optimum chained list in VPNv4 routing table, if so, and execution step 604, otherwise execution step 603.

Step 603, is stored in local VPNv4 routing table by the route of receiving, carries out preferably, preferably rear activation according to preference rule.

Step 604, if the route of receiving is equal-cost route, and OPT in equivalent marking attribute is set to 00, and and the ECMP ID of local all same prefix is unequal, this route is left in to local VPVv4 routing table, carry out preferably according to preference rule, preferably rear activation.

If the route of receiving is equal-cost route, and the OPT position information in equivalent marking attribute is shown as Article 1 equal-cost route, be that OPT is set to 10 route, all routes of this prefix in local routing table are carried out to mark, such as be all labeled as stale state, then according to ECMP ID, all routes of this prefix are upgraded, upgrade one, need to be by the tag delete of this route, until receive the last item equal-cost route, OPT is set to 01 route.After renewal finishes, will still there is described mark, as the route of stale is deleted.Finally, according to preference rule, the route of upgrading is carried out preferably, preferably rear activation.

If the route of receiving is non-equivalence route, according to prior art processing.

Step 605, iterates to public network tunnel by the equal-cost route in VPNv4 routing table.

When equal-cost route in VPNv4 routing table is iterated to public network tunnel, equal-cost route in VPNv4 routing table is put into the routing table of corresponding VPN, preferred in VPN routing table, can in VPN routing table, form of equal value with the route of different RD, the condition of equivalence is to have identical local first level, AS_PATH, MED and Origin attribute.On this PE, if the equal-cost route optimizing is the route in VPNv4 table, to receive after message, the public network tunnel forming by the present invention E-Packets, otherwise by existing techniques in realizing message repeating.

The more new routing information sending is not got rid of and be there will be abnormal conditions, if there is abnormal conditions, in the present embodiment, if the ICMP ID receiving is 0, represents to occur extremely, only retaining this route.If receive the route of identical RD and prefix before, this route is override to the route of all identical RD and prefix.

Continue below take Fig. 3 as example, illustrate route learning process and message repeating process, dotted line is route propagation process, and solid line is traffic forwarding process.Route is sent to respectively PEA and PEB by CE1.The route of CE1 is sent to PEC by PEA and PEB, give respectively this route assignment label separately to PEC simultaneously, when PEC using these two routes when equal-cost route reflects to PED, above-mentioned label is resumed to PED, at this moment on PED, had to the public network tunnel of PEA and PEB.PED equivalence optimizes 2 routes, activates these two routes and forms of equal value.Down hop is respectively PEA and PEB, there is again the public network tunnel to PEA and PEB simultaneously, can iterate to public network tunnel, claim to be Ta to the tunnel of PEA, tunnel to PEB is called Tb, so just can form two paths: 1, PED->P1->PEA-> CE1; 2, PED->P2->PEB-> CE1; Just can carry out normal message repeating.As, there is flow to forward from CE2, destination address matches route, and CE2 is by traffic forwarding to PED, and there is equal-cost route in route on PED, under by flow forwarding pattern, can walk one of them route, and HASH is to path 1 here; On CE3, also have flow to forward, destination address matches route, in the time that flow arrives PED, can from two paths, select one, and HASH is to path 2.Flow can form of equal value forwarding on public network and in private network like this.The present invention realizes VPNv4 route equivalence on PE, send equal-cost route by BGP to VPNv4 neighbours, in VPNv4 and VPN, form equal-cost route, on public network, form private network route equivalence, and then in the time forwarding VPN message, realize comprehensively of equal value forwarding of private network and public network flow.

In addition, based on the inventive concept same with said method, the invention allows for the PE in a kind of Layer3 Virtual Private Network.

Fig. 7 is the PE structural representation in L3VPN of the present invention.As shown in Figure 7, this PE comprises: route receiver module 701, equal-cost route preferred module 702, equal-cost route identity property increase module 703, equal-cost route sending module 704 and equal-cost route iteration module 705.

Route receiver module 701, for receiving the route of sending from downstream PE, preserves and sends to equal-cost route preferred module 702.

Equal-cost route preferred module 702, is connected with route receiver module 701, carries out equivalence preferably for the route that route receiver module 701 is received, and the equal-cost route optimizing sends to equal-cost route identity property to increase module 703.

The preference rule of equal-cost route preferred module 702 is mentioned above, repeats no more.

Equal-cost route identity property increases module 703, is connected with equal-cost route preferred module 702, and one or more equal-cost route going out for parity price routing optimization increases equal-cost route identity property.

Equal-cost route identity property increases module 703 and further comprises: route judge module 7031, is used for judging after routing optimization, neighbor state changes or configure and change, and whether triggers routing update.

If trigger routing update, described route is sent to equal-cost route mark increase module 703, otherwise described route is sent to equal-cost route sending module 704.

The method of the form of equivalent marking attribute and increase equivalent marking attribute as described above, repeats no more.

Equal-cost route sending module 704, increases module 703 with equal-cost route identity property and is connected, and the equal-cost route that increases equal-cost route identity property is sent to upstream PE or CE.

Equal-cost route iteration module 705, increases module 703 with equal-cost route identity property and is connected, and the equal-cost route that increases attribute-bit is activated, and iterate to public network tunnel.

Wherein, modules of the present invention can be integrated in one, and also can separate deployment.Above-mentioned module can be merged into a module, also can further split into multiple modules.

The foregoing is only preferred embodiment of the present invention, in order to limit the present invention, within the spirit and principles in the present invention not all, any modification of making, be equal to replacement, improvement etc., within all should being included in the scope of protection of the invention.

Claims

1. a generation method for Layer3 Virtual Private Network equal-cost route, is characterized in that, the method comprises:

A, service provider edge router PE preserve the route receiving from downstream PE, and the row equivalent routing optimization of going forward side by side, for the equal-cost route optimizing increases equal-cost route identity property and activates;

2. method according to claim 1, is characterized in that, described equal-cost route identity property comprises the equal-cost route identification number ECMP ID for distinguishing equal-cost route; The described method that increases equal-cost route identity property for the equal-cost route that optimizes is: for equal-cost route corresponding to same prefix distributes different ECMP ID.

3. method according to claim 1 and 2, it is characterized in that, described equal-cost route method for optimizing is: in the interim optimum chained list in VPNv4 routing table, preferably have the route of the maximum route of route, the Preferred-value value in public network tunnel, route that local first level is the highest, polymerization route, autonomous system AS shortest path, route that ORIGIN type level is high, the preferred minimum route of Multi-Exit Discriminator attribute med value; According to the route of preserving to the selective sequential of Internal BGP IBGP from External BGP EBGP, alliance; In the time that the route number optimizing is less than or equal to default maximum equal-cost route number, preferably complete, in the time that the route number optimizing exceedes default maximum equal-cost route number, get at random the route of default maximum equal-cost route number as equal-cost route number;

Or, in interim optimum chained list in VPNv4 routing table, preferably have the maximum route of route, the Preferred-value value in public network tunnel, route that local first level is the highest, polymerization route, the route of AS shortest path, the minimum route of route, med value that ORIGIN type level is high; According to the route of preserving to the selective sequential of IBGP from EBGP, alliance the preferred minimum route of down hop public network route Cost value; In the time that the route number optimizing is less than or equal to default maximum equal-cost route number, preferably complete, in the time that the route number optimizing exceedes default maximum equal-cost route number, get at random the route of default maximum equal-cost route number as equal-cost route number.

4. method according to claim 2, it is characterized in that, the method further comprises: in the time that needs send renewal route to neighbours, if sent the route of upgrading therewith the same prefix of route before, and this renewal route is equal-cost route, for increasing equal-cost route identity property in preferred condition without the route of equal-cost route identity property with the same prefix of this renewal route, if this renewal route is non-equivalence route, will remove with the equal-cost route identity property of the route in not preferred state of the same prefix of this renewal route; If do not send the route of upgrading therewith the same prefix of route before, and this renewal route is equal-cost route, is this route assignment equal-cost route identity property; The equal-cost route of the same prefix that has equal-cost route identity property is sent to upstream PE.

5. method according to claim 4, it is characterized in that, described send to upgrade when route to neighbours be: re-start routing optimization, preferably route changes, neighbor state changes, configuration variation, or neighbours' refresh requests, send renewal route to neighbours while having triggered the renewal of route.

6. method according to claim 2, is characterized in that, the method further comprises: if when abnormal conditions appear in ECMP ID in the attribute-bit of the renewal route sending, only retain this route; If receive with described ECMP ID and occur that the route of abnormal conditions has the route of identical route-distinguisher RD and prefix, override the route of all identical RD with it and prefix by this route before.

7. method according to claim 2, it is characterized in that, the method that in described steps A, PE preserves the route receiving from downstream PE is: the route of receiving is left in transit shed, search in the interim optimum chained list in VPNv4 routing table according to the prefix of route and route-distinguisher RD attribute, the route of the corresponding prefix of if there is no receiving, leaves the described route of receiving in local VPNv4 routing table; If there is the route of the corresponding prefix received, and described in the route received be equal-cost route, determine that according to the equivalent marking attribute of route route stores local VPNv4 routing table or renewal into.

8. method according to claim 7, is characterized in that, described equal-cost route identity property further comprises: for representing the action identification OPT of routing update state;

The described method that increases equal-cost route identity property for the equal-cost route that optimizes further comprises: for route corresponding to same prefix, the OPT of the route that will upgrade is at first designated Article 1 equal-cost route, and route OPT that will final updating is designated the last item equal-cost route;

9. a Layer3 Virtual Private Network retransmission method of equal value, is characterized in that, the method comprising the steps of:

B, be PE for upstream equipment, increased the equal-cost route of equal-cost route identity property and send to upstream PE optimizing; Be user network boundary device CE for upstream equipment, by optimizing the equal-cost route that has increased equal-cost route identity property, iterate to public network tunnel;

C, PE receive the message that CE sends, and the route optimizing in local VPN table is the preferred route of described equivalence, send to target CE with described public network tunnel; Otherwise send message by the local preferably public network tunnel that route forms.

10. method according to claim 9, it is characterized in that, in described step C, PE further comprises after receiving the message that CE sends: under by flow forwarding pattern, determine a paths by HASH algorithm, the message of receiving is sent to target CE by this path.

Service provider edge router PE in 11. 1 kinds of Layer3 Virtual Private Network, it is characterized in that, this PE comprises: route receiver module, equal-cost route preferred module, equal-cost route identity property increase module, equal-cost route sending module and equal-cost route iteration module;

Described equal-cost route preferred module, is connected with described route receiver module, carries out equivalence preferably for the route that described route receiver module is received, and the equal-cost route optimizing sends to described equal-cost route identity property to increase module;

Described equal-cost route identity property increases module, is connected with described equal-cost route preferred module, increases equal-cost route identity property for the equal-cost route that described equal-cost route preferred module is optimized;

12. PE according to claim 11, it is characterized in that, described equal-cost route identity property increases module and further comprises: route judge module, described route judge module is used for judging after routing optimization, neighbor state changes or configuration variation, whether trigger the renewal of route, if so, send to described equal-cost route identity property to increase module described route, otherwise described route is sent to described equal-cost route sending module or described equal-cost route iteration module.