CN1960366A

CN1960366A - Cross-domain connection method of label exchange virtual dedicated network in multiprotocol

Info

Publication number: CN1960366A
Application number: CNA2005101009127A
Authority: CN
Inventors: 马汝胜; 李虹; 许生海; 伏朝晖; 朱超国
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2005-10-31
Filing date: 2005-10-31
Publication date: 2007-05-09
Anticipated expiration: 2025-10-31
Also published as: CN100571264C

Abstract

The method comprises: starting label distribution protocol between autonomic system edge routers; using the layer-2 label to switch traffic; starting MPBGP protocol between autonomic system edge routers, and using non direct connection address to build MPBGP neighbor; on the autonomic system edge routers, configuring the non direct address routing protocol pointing to the domain of opposite side, and shielding other routes being needless. In the invention, the LDP and MPBGP neighbors are built between ASBRs by using non direct connection address so as to use lower layer routing protocol to implement load balance and route backup.

Description

A kind of cross-domain connection method of label exchange virtual dedicated network in multiprotocol

Technical field

The present invention relates to the router technology field in the communication network, refer more particularly to the cross-domain interconnection technique field of three-layer VPN.

Background technology

VPN (VPN (virtual private network)) business is one of telecommunication service of new generation of tool potentiality.Realize that based on the Multi-Protocol Label Switch (MPLS) network technology of VPN improved the defective of traditional IP greatly, can provide the fail safe the same to guarantee simultaneously again, adapted to the demand of vpn service well with the frame relay/atm network.Traditional IP network is all carried out the 3rd layer route querying at each routing node, and the time-delay of total capaciated flow network is bigger; Traditional IP network can't provide good fail safe for user's private network; Traditional network QOS do neither be very good.The appearance of MPLS technology is fine to be solved these problems, and the especially release of MPLS VPN can provide abundant business to the user on IP network.Each telecommunications producer all in the product of oneself, has increased the support to MPLS VPN, to adapt to the variation that telecommunication market develops rapidly.

When making up MPLS VPN network, often need to cross over a plurality of autonomous systems, even cross over a plurality of different operators.At this time the problem that need consider of the MPLS VPN of Kua Yueing is just many, mainly contains following Several Factors:

1, whether the route of autonomous system domains leaks mutually;

2, stride the how route of switched vpc N of autonomous system;

3, to the influence of the other side's autonomous system how cross-domain MPLS VPN.

Each top problem all needs careful consideration and research.The route of switched vpc N between different operators how, do not influence the normal route calculation of the other side's autonomous system, in other words the other side is produced minimum influence, three kinds of cross-domain connection methods of three-layer VPN introduced in one piece of article on the juniper website " BGP/MPLS VPN Hierarchical and RecursiveApplications ", and describe the exchanged form of label in detail.

Wherein, the connected mode of second kind of leap is on the border router of two cross-domain connections (ASBR), uses the address of direct-connected interface to set up MP-EBGP neighbours, comes the label of switched vpc N.The deficiency of this mode maximum is that the interface of setting up MP-EBGP neighbours is relied on very much.Can not normally move if set up this interface, will cause the failure of cross-domain MPLS VPN.Especially can not handle following situation flexibly:

The router of two cross-domain connections (representing with ASBR-A and ASBR-B respectively), the ASBR-A router has two interface A1, and A2 is connected respectively to the B1 of ASBR-B router, the B2 interface.ASBR-A router and ASBR-B router have two interconnected circuit (A1-B1 like this, A2-B2), if on the circuit of A1-B1, pass through two straight chain interface A1 of router, B1 sets up the neighbours of cross-domain MP-EBGP, when the A1-B1 line failure, overstate that the ASBR-A in territory and ASBR-B MPLS-VPN just can't operate as normal, though this time A2-B2 the circuit operate as normal.

Summary of the invention

Technical problem to be solved by this invention is: solve in the prior art, set up cross-domain connection to the problem that the interface of setting up MP-EBGP neighbours relies on very much, propose a kind of new connected mode.

Technical scheme of the present invention is to go up the route that adopts MP-BGP (MPBGP) and tag distribution protocol (LDP) switched vpc N at Autonomous System Boundary Router, AS Boundary Router (ASBR).

Particularly, can may further comprise the steps:

Step 1, between Autonomous System Boundary Router, AS Boundary Router (ASBR), enable tag distribution protocol (LDP agreement), adopt two-layer label to come switching traffic;

Step 2, between Autonomous System Boundary Router, AS Boundary Router (ASBR), enable the MPBGP agreement, adopt the indirectly connected address of Autonomous System Boundary Router, AS Boundary Router to set up MPBGP neighbours;

Step 3, point to the Routing Protocol of the indirectly connected address in the other side territory, shield other unwanted routes in Autonomous System Boundary Router, AS Boundary Router configuration.

We are compared with prior art bright, following advantage:

1, adopt indirectly connected address (as LOOPBACK) to set up LDP and MPBGP neighbours between the ASBR, more unified with the LDP MPBGP configuration style of other routers in the entire domain.

2, ASBR sets up MPBGP LDP neighbours by indirectly connected address, can use the Routing Protocol of lower floor to realize load balancing and route backup.

Description of drawings

Fig. 1 is the most basic networking diagram in the cross-domain connected mode of a kind of VPN;

Fig. 2 is to be the label distribution process schematic diagram of example with the concrete route of certain bar among Fig. 1;

Fig. 3 is to be the flow transport process schematic diagram of example with the concrete route of certain bar among Fig. 1.

Embodiment

In the present invention, if two routers all move MPBGP in same autonomous system, claim that the MPBGP between these two routes is MP-IBGP (a multi-protocols Internal BGP); If two routers claim that at different autonomous system operation MPBGP the MPBGP that moves between these two routers is MP-EBGP.

As shown in Figure 1, concrete connected mode is as follows:

1, R1 (PE1) and R2 (ASBR1) set up MP-IBGP neighbours, and the vpn label of the VPN of R1 is exchanged to R2; R1 (PE1) and R2 (ASBR1) are in same territory.

R1 router and R2 router are served as the functional role difference in Fig. 1 as follows:

The R1 router is a pe router, is responsible for three-layer VPN user's access; The R1 router is the router in the autonomous system domains, does not generally set up MP-EBGP and LDP neighbours with other autonomous systems router outward.

The R2 router is a core router, the forwarding capability of responsible three-layer VPN only, not responsible three-layer VPN user's access; The R2 router is the router of striding autonomous system domains, and router general and other autonomous system is set up MP-EBGP and LDP neighbours.

Pe router (supplier's border router) is responsible for the access of three-layer VPN on function.The function of representing this router to serve as with PE is also refered in particular to the router of serving as the three-layer VPN access function traditionally.

2, set up LDP neighbours between R1 (PE1) and R2 (ASBR1), the LDP agreement will be set up the outer layer label path from R1 (PE1) to R2 (ASBR1).

3, R4 (PE2) and R3 (ASBR2) set up MP-IBGP neighbours, and the vpn label of the VPN of R4 is exchanged to R3; R4 (PE2) is in another different territory with R3 (ASBR2).

4, set up LDP neighbours between R4 (PE2) and the R3 (ASBR2), the LDP agreement will be set up the outer layer label path from R4 (PE2) to R3 (ASBR2).

5, R2 (ASBR1) and R3 (ASBR2) are increased to the route of the indirectly connected address of the other side mutually, as increasing the static routing of pointing to the other side loopback address.

6, between R2 (ASBR1) and R3 (ASBR2), pass through indirectly connected address,, set up the neighbours of MP-EBGP as the loopback address.

7, set up LDP neighbours between R2 (ASBR1) and the R3 (ASBR2), as on direct-connected circuit (fa0/0-fa0/0) open the LDP agreement.

Fig. 2 is a label distribution process schematic diagram, and the process of distribution label is:

1, R1 distributes outer layer label and distributes vpn label to MPBGP neighbours R2 to adjacent LDP neighbours;

2, R2 is to adjacent MP-EBGP and LDP neighbours R3 distribution vpn label and outer layer label;

3, R3 distributes outer layer label and vpn label to adjacent LDP and MP-IBGP neighbours R4.

After connecting according to above-mentioned connected mode, the mode that cross-domain VPN flow transmits as shown in Figure 3:

1, because next jumping that ASBR1 announces to the VPN route of PE1 is ASBR1 itself, cross-domain the arrivals PE2 router VPN flow that PE1 sets out exchanges arrival ASBR1 according to outer layer label.

2, outer layer label was ejected after packet arrived ASBR1, only remaining vpn label, ASBR1 directly searches three-layer VPN vpn label route, finds next to jump (loopback of the other side ASBR2), and then searches route and the label of the loopback of the other side ASBR2 according to next jumping.

3, the vpn label that finds according to step 2 exchanges to the other side ASBR2 to the three-layer VPN flow, thereby finishes cross-domain process.

Claims

1, a kind of cross-domain connection method of label exchange virtual dedicated network in multiprotocol, the route of employing MPBGP and tag distribution protocol secure virtual private network on Autonomous System Boundary Router, AS Boundary Router.

2, the described cross-domain connection method of label exchange virtual dedicated network in multiprotocol of claim 1 is characterized in that,

Step 1, between Autonomous System Boundary Router, AS Boundary Router, enable tag distribution protocol, adopt two-layer label to come switching traffic;

Step 2, between Autonomous System Boundary Router, AS Boundary Router, enable the MPBGP agreement, adopt the indirectly connected address of Autonomous System Boundary Router, AS Boundary Router to set up MPBGP neighbours;

3, the described cross-domain connection method of label exchange virtual dedicated network in multiprotocol of claim 2, it is characterized in that, set up MP-IBGP neighbours and tag distribution protocol neighbours between two routers in same territory, the Autonomous System Boundary Router, AS Boundary Router of same area is not enabled Routing Protocol, learn the route of the indirectly connected address of the other side, and set up neighbours and the tag distribution protocol neighbours of MP-EBGP by indirectly connected address.

4, claim 2 or 3 described cross-domain connection method of label exchange virtual dedicated network in multiprotocol is characterized in that, described indirectly connected address is meant the lookback address.

5, the described cross-domain connection method of label exchange virtual dedicated network in multiprotocol of claim 3 is characterized in that, described Routing Protocol is that static routing protocol also can be a dynamic routing protocol.