JP5830320B2 - Route reflector device, route control method, and network system - Google Patents

Description

  The present invention relates to a route reflector device, a route control method, and a network system.

  BGP (Border Gateway Protocol) exists as a routing protocol for exchanging route information between providers. In this BGP, all IBGP (Internal BGP) routers belonging to a predetermined AS (Autonomous System) are prohibited from transmitting the route information received from the IBGP router to other IBGP routers. Need to connect. Specifically, if there are N IBGP routers in the AS, there will be N (N-1) / 2 IBGP sessions, so a lot of resources and bandwidth are needed to maintain these sessions. Consume.

  Therefore, as shown in Patent Document 1, one of the IBGP routers constituting the AS is set as a server called a route reflector, and the other IBGP router is set as a client. By doing in this way, the client sets peering only with the route reflector, so that the number of sessions is small, and peering can be performed in a star type that is easier to manage.

  By the way, in MPLS VPN (Multi Protocol Label Switching Virtual Private Network), an identifier for distinguishing VPN called RT (Route-target) is given to route information distributed from PE. In other PEs that have received the route information distributed from the PE, if the reception of the RT assigned to the route information is permitted, the route information is registered in the route table to form a VPN.

  When a route reflector distributes a route to a PE (Provider Edge) that is a client, it is necessary to distribute only a route permitted by each PE. Therefore, conventionally, a filter called an RT filter is attached to the route reflector. Provided and distributes route information based on this RT filter. By using such an RT filter, it is possible to prevent unnecessary route information from being distributed from the route reflector to the PE, and thus the burden on the network can be reduced.

Japanese Patent Laid-Open No. 2004-247871

  By the way, conventionally, when a new VPN is added, changed, or deleted to the PE, it is necessary to manually update the RT filter of the route reflector. Therefore, it is necessary to update every time a VPN is added. Therefore, there is a problem that time and cost are required.

  Therefore, an object of the present invention is to provide a route reflector device, a route control method, and a network system that do not require labor for changing an RT filter.

In order to solve the above-mentioned problems, the present invention provides a route reflector device for transferring route information transmitted from a BGP router that performs routing by BGP to another BGP router, in which a VPN is added to the BGP router, When the route information transmitted from the BGP router is received due to the change of the VPN or the deletion of the existing VPN, the route target information included in the route information and the route The first storage that constructs the first database by associating and storing the address information of the BGP router that transmitted the information, the route target information acquired by the acquiring means, and the address information in association with each other and means, second storing means for constructing a second database by storing the route information, wherein B When receiving the route information transmitted from the P router, a route target information included in the route information specified from the first database, the address information that is correlated with the route target information identified reference, that having a, a transmitting means for transmitting the route information extracted from the second database.
According to such a configuration, the trouble of changing the RT filter can be omitted.

According to another aspect of the invention, in addition to the above invention, the first storage unit registers new information in the first database when the VPN is added, and changes the VPN when the VPN is changed. The information registered in the first database is changed, and when the VPN is deleted, the corresponding information is deleted from the first database , and the second storage means is configured when the VPN is added. Registers new information in the second database, changes the information registered in the second database when the VPN is changed, and changes the information stored in the second database when the VPN is deleted. Delete the corresponding information.
According to such a configuration, even when a VPN is added, changed, or deleted, information about the route target can be appropriately managed.

According to another invention, in addition to the above-described invention, when the VPN is added to the BGP router, the transmission means transmits the route information of the existing BGP router to the BGP router to which the VPN is added. It transmits to it, It is characterized by the above-mentioned.
According to such a configuration, it becomes possible to reliably transmit route information to all BGP routers.

In the route control method of transferring route information transmitted from a BGP router that performs routing by BGP to another BGP router, a VPN is added to the BGP router, an existing VPN is changed, or When the route information transmitted from the BGP router is received due to the deletion of the existing VPN, the route target information included in the route information and the BGP router that transmitted the route information The acquisition step of acquiring the address information of the first , the first storage step of constructing the first database by associating the route target information acquired in the acquisition step with the address information and storing in the first storage means When the second storage scan building a second database by storing the route information in the second storage means And-up, when receiving the route information transmitted from the BGP router, a route target information included in the route information specified from said first database is correlated with the route target information identified and which refers to the address information, that having a, a transmission step of transmitting the path information extracted from the second database.
According to such a method, the trouble of changing the RT filter can be omitted.

Further, the present invention provides a network system having a plurality of BGP routers that perform routing by BGP and a route reflector device that transfers route information transmitted from the BGP router to another BGP router. Included in the route information when the route information transmitted from the BGP router is received due to the VPN being added to the BGP router, the existing VPN being changed, or the existing VPN being deleted Storing the route target information, the acquisition means for acquiring the address information of the BGP router that transmitted the route information, the route target information acquired by the acquisition means, and the address information in association with each other. , storing a first storage means for constructing a first database, the route information A second storing means for constructing a second database Rukoto, when receiving the route information transmitted from the BGP router identifies the route target information included in the route information from the first database, It refers to the address information that is correlated with the route target information specified, that having a, a transmitting means for transmitting the route information extracted from the second database.
According to such a system, the trouble of changing the RT filter can be omitted.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the route reflector apparatus which does not require the effort of change of RT filter, the route control method, and a network system.

It is a figure which shows the structural example of the network system which concerns on embodiment of this invention. It is a block diagram which shows the structural example of the route reflector apparatus shown in FIG. It is a figure which shows the structural example of the network system of the state in which CE50,60 is not accommodated. It is a figure which shows the structural example of the network system of the state in which CE60 is not accommodated. It is a figure which shows an example of the information stored in RT filter DB. It is a figure which shows an example of the information stored in path | route information DB. It is a flowchart for demonstrating the flow of the process performed in FIG.

  Next, an embodiment of the present invention will be described.

(A) Description of Configuration of Embodiment FIG. 1 is a diagram illustrating a configuration example of a network system according to an embodiment of the present invention. The network shown in FIG. 1 includes an RR (Route Reflector) 10, PE (Provider Edge) 20 to 40, and CE (Customer Edge) 50 and 60. The network system shown in FIG. 1 is, for example, an IP-VPN (Internet Protocol Virtual Private Network), and operates based on, for example, MPLS (Multi Protocol Label Switching).

  Here, the RR 10 and the PEs 20 to 40 are networks on the carrier side, constitute a backbone network of a plurality of VPNs, assign a label to a layer 3 packet (IP packet) based on MPLS, and based on this label Forward the packet. The PEs 20 to 40 are routers located at the edge of the backbone network, have different routing tables and VRF (Virtual Routing Forwarding) tables for each user, and exchange routing information distributed from users among users of the same VPN. Thus, a VPN for each user is realized on the same backbone network.

  The CEs 50 and 60 are site routers arranged on the user side, and have a function of connecting the user side network to the backbone network.

  The RR 10 realizes a server-client type connection with the PEs 20 to 40, and reflects (reflects) the route information transmitted from the PE that is the client to other PEs. Further, the RR 10 transfers the route information to the corresponding PE based on the route target (RT). The route target is information for establishing VPN membership.

  FIG. 2 is a diagram illustrating a configuration example of the RR 10. As shown in FIG. 2, the RR 10 includes a reception processing unit 11, a route information processing unit 12, a route information DB (Data Base) 13, an RT (Route Target) filter DB 14, a filter processing unit 15, and a transmission processing unit 16. have.

  Here, the reception processing unit 11 receives the route information transmitted from the PEs 20 to 40 and supplies the route information to the route information processing unit 12. The route information processing unit 12 registers the route information received by the reception processing unit 11 in the route information DB 13 and the RT filter DB 14 as necessary.

  The route information DB 13 is a database that stores route information indicating the route from the CE to the PE. The RT filter DB 14 is a database that stores filter information for filter linking route information based on a route target.

  The filter processing unit 15 performs a filtering process on the route information based on information stored in the RT filter DB 14.

  The transmission processing unit 16 performs processing for transmitting the route information that has not been filtered (discarded) by the filter processing unit 15 to the PE with reference to the route information registered in the route information DB 13.

  Next, the operation of the above embodiment will be described.

  First, as shown in FIG. 3, it is assumed that the CEs 50 and 60 are not connected (accommodated). In this state, assume that CE 50 is connected to PE 20 and VRF A for configuring VPN A is set in PE 20 as shown in FIG. Note that the address of the network connected by the CE 50 is 192.168.1.0/24 (where / 24 is a prefix), the address of the PE 20 is 1.1.1.1, and RT Is 1: 100.

  When the connection is completed, a routing process is executed between the PE 20 and the CE 50, and communication is established between them. After that, the PE 20 is “192.168.1.0/24” which is the address of the network connected to the CE 50, “1.1.1.1” which is the address of the PE to which the CE 50 is connected, and The information including the route target “1: 100” is advertised (transmitted) to the RR 10 as route information. The route information includes other information, but the description thereof is omitted here for the sake of simplicity.

  In the RR 10, such route information is received by the reception processing unit 11 and delivered to the route information processing unit 12. The route information processing unit 12 refers to the RT filter DB 14 and determines whether or not filter information corresponding to the received route information is registered. FIG. 5A shows an example of information registered in the RT filter DB 14. In the example of FIG. 5A, filter information regarding PEs 20 to 40 is registered. Specifically, first, the advertisement of the information of “3.3.3.3” which is the address of the PE 40 and the information of the route target “1: 200” is “permit” (permitted), and others (others) ) Is registered as a rule that sets the advertisement of the route target information to “deny”. Secondly, a rule is registered in which “1.1.1.1” which is the address of the PE 20 and all (all) route targets are “deny” (non-permitted). Third, a rule is registered in which “2.2.2.2” which is the address of the PE 30 and all (all) route targets are “deny” (non-permitted). Accordingly, since the filter information corresponding to the received route information is not registered in the RT filter DB 14, it is determined that it is not registered.

  As a result, the route information processing unit 12 registers the filter information in the RT filter DB 14. FIG. 5B shows an example of information registered in the RT filter DB 14 at this time. In this example, the information of PE 20 is updated and registered. Specifically, “1.1.1.1” which is the address of PE 20 is stored, “1: 100” and “Permit” are stored as application rules, and “others” and “deny” are stored. Has been. That is, for the route target “1: 100”, a rule for permitting “Permit” for the advertisement is applied. For “others” and “deny”, a rule that does not advertise other route targets is applied.

  Next, the RR 10 registers the route information in the route information DB 13. FIG. 6A shows an example of route information registered in the route information DB 13 in the state of FIG. In the example of FIG. 6A, “192.168.3.0/24” is stored as the first item “No. 1” as the network address (Network), and the next hop to the network ( Next, “3.3.3.3” is stored as “Nexthop”, and “1: 200” is stored as the route target (RT). In such a state, when the route information of the PE 20 is newly registered, the state shown in FIG. In the example of FIG. 6B, “192.168.1.0/24”, which is the network address (Network), is stored as the second item “No. 2”, and the next hop to the network is stored. “1.1.1.1” is stored as (Next), and “1: 100” is stored as the route target (RT).

  Next, the RR 10 refers to the RT filter DB 14 to determine whether or not there is another PE whose route target “1: 100” is “permit”. To advertise route information. In this example, since the PE that is “permit” is only the PE 20 that has transmitted the route information, it is determined that there is no other PE, and the route information is not advertised.

  Next, assume that CE 60 is connected to PE 30 and VRF A for configuring VPN A is set in PE 30. Note that the network address connected by the CE 60 is 192.168.2.0/24, the PE 30 address is 2.2.2.2, and RT is 1: 100.

  When the connection is completed, a routing process is executed between the PE 30 and the CE 60, and communication is established between them. Thereafter, the PE 30 is “192.168.2.0/24” which is the address of the network connected to the CE 60, “2.2.2.2” which is the address of the PE to which the CE 60 is connected, and The information including the route target “1: 100” is advertised to the RR 10 as route information.

  In the RR 10, such route information is received by the reception processing unit 11 and delivered to the route information processing unit 12. The route information processing unit 12 refers to the RT filter DB 14 and determines whether or not filter information corresponding to the received route information is registered. In this example, since the filter information related to the PE 30 is not registered, it is determined that it is not registered, and the filter information related to the PE 30 is newly registered as shown in FIG. In the example of FIG. 5C, the route target “1: 100” is “permit” as the filter information related to the address “2.2.2.2” of the PE 30, and “others” is “deny” other than that. Rules are registered.

  Further, the RR 10 registers the received route information in the route information DB 13. FIG. 6C shows a state in which route information related to the PE 30 is additionally registered. In this example, “192.168.2.0/24” is stored as the network address (Network) and “2.2.2.2” is stored as the next hop (Nexthop) to the network. “1: 100” is stored as the route target (RT).

  Next, the RR 10 refers to the RT filter DB 14 to determine whether or not there is another PE whose “1: 100” is “permit”. Advertise information. In the present example, as shown in FIG. 5C, the PE 20 whose address is “1.1.1.1” is “permit”, so the route information is advertised to the PE 20. The PE 20 that has received the advertisement of the route information has the route target “1: 100” and the address “192.168.2.0/ Knows that 24 "network is connected.

  Subsequently, the RR 10 transfers the route information of the existing PE having the same route target to the PE 30 to the PE 30 to which the CE 60 is newly connected. Specifically, since the route information of the PE 20 having the route target “1: 100” has not been transferred to the PE 30, the route information of the PE 20 is transferred to the PE 30. The PE 30 that has received the transfer of the route information has the route target “1: 100” and the address “192.168.1.0/ Knows that 24 "network is connected.

  Although the above example is an operation when a new VPN is accommodated (added) in the PE, the filter information can be automatically updated even when the VPN is changed or deleted. . Specifically, when changed, new route information is transmitted to the RR 10 from the PE whose VPN has been changed. In the RR 10, filter information based on the received route information is overwritten in the RT filter DB 14. Thereby, the filter information can be updated. When the VPN is deleted from the PE, route information including a command for requesting deletion of filter information is transmitted from the PE from which the VPN has been deleted. In RR10, filter information is deleted based on the received route information. Thereby, the filter information can be deleted.

  With the above operation, information for filtering the route information is extracted and registered in the RT filter DB 14 of the RR 10 according to the contents of the route target. The trouble of registering can be omitted.

  Next, a flowchart for realizing the operation of the above embodiment will be described. FIG. 7 is a flowchart for explaining the flow of processing executed in the route reflector device 10 shown in FIG. When this flowchart is started, the following steps are executed.

  In step S <b> 10, the reception processing unit 11 receives the route information transmitted from the PE and supplies the route information to the route information processing unit 12. The route information is specifically information including a network address, a PE address to which the CE is connected, and a route target. Actually, the route information includes information such as RD (Route Distinguisher) other than this, but is omitted here for simplification of description.

  In step S11, the route information processing unit 12 refers to the RT filter DB 14, determines whether or not the filter information related to the route information received in step S10 has been registered, and if it has been registered (step S11: Yes). Proceeds to step S12, otherwise proceeds to step S13 (step S11: No). For example, in the state shown in FIG. 3, as shown in FIG. 5A, only the filter information related to PE 40 is registered. In this state, when the CE 50 is newly accommodated in the PE 20, the route information including the route target “1: 100” is transmitted from the PE 20, and the information of the route target “1: 100” is not registered. Therefore, it determines with No in step S11, and progresses to step S12.

  In step S12, the route information processing unit 12 registers new filter information in the RT filter DB 14. In this example, since the information about the route target “1: 100” is not registered, the route “1.1.1.1” corresponding to the PE 20 is routed as shown in FIG. Filter information for “permit” the target “1: 100” and “deny” for “others” is newly registered.

  In step S13, the route information processing unit 12 overwrites and registers new information on the already registered filter information. For example, when the route information is changed, the new filter information is overwritten on the existing filter information, so that the filter rule can be changed.

  In step S14, the route information processing unit 12 registers a route advertisement event for the PE that has transmitted the route information. Specifically, an event for transmitting the already registered route information is registered to the PE that has transmitted the route information. When this event is registered, Yes is determined in step S20, and the event is executed in S21.

  In step S15, the route information processing unit 12 registers the route information received in step S10 in the route information DB 13. In the present example, since CE 50 is newly accommodated in PE 20, No. 5 in FIG. 2 is newly registered.

  In step S <b> 16, the filter processing unit 15 acquires route information from the route information processing unit 12, extracts a route target, and refers to filter information corresponding to the extracted route target from the RT filter DB 14. In the present example, as shown in FIG. 5 (B), information regarding the PE 20 is registered as the filter information having the route target “1: 100”, so this information is referred to.

  In step S17, the filter processing unit 15 determines whether or not there is another permit (permitted) PE in the filter information having the route target referred to in step S16 (step S17). In step S17: Yes, the process proceeds to step S18. In other cases (step S17: No), the process proceeds to step S19. In this example, as the filter information having the route target “1: 100”, as shown in FIG. 5 (B), information related to the PE 20 is registered, but this PE 20 uses the route information received in step S10. Since there is no information having the route target “1: 100” other than the transmission source that has transmitted, it is determined No in step S17 and the process proceeds to step S19. In the state where the information registered in the RT filter DB 14 is in the state as shown in FIG. 5B, when the route information whose route target is “1: 100” is transmitted from the PE 30, the PE 20 has the route target “1: 100 ”and“ permit ”, the route information is advertised to the PE 20.

  In step S <b> 18, the filter processing unit 15 permits advertisement of route information to the PE that has been permitted. For example, when the filter information shown in FIG. 5B is registered and the route information having the route target “1: 100” is received from the PE 30, the PE 20 relates to the route target “1: 100”. Therefore, the filter processing unit 15 supplies this route information to the transmission processing unit 16. The transmission processing unit 16 refers to the route information registered in the route information DB 13 and transmits the route information to the PE 20. The PE 20 that has received this path information knows that the VPN A is accommodated in the PE 30.

  In step S19, the filter processing unit 15 discards the route information that is not permitted without advertising. For example, when the CE 50 is connected to the PE 30 in the state shown in FIG. 3, the filter information that has been submitted does not exist other than the PE 20 that is the transmission source, and therefore the route information transmitted from the PE 20 is discarded.

  In step S20, the route information processing unit 12 determines whether or not a route advertisement event is registered, and if it is registered (step S20: Yes), the process proceeds to step S21, and otherwise (step S20). : No), the process ends. More specifically, if a route advertisement event is registered in step S14, the process proceeds to step S21.

  In step S21, the route information processing unit 12 executes a route advertisement event. More specifically, for example, when the CE 60 is connected after the CE 50 is connected in the state of FIG. 3, the filter information about the PE 20 is registered when the CE 60 is connected. Advertised to However, the route information of PE 20 does not reach PE 30. Therefore, in the present embodiment, when new filter information is registered, a route advertisement event is registered in step S14, and in step S21, a registered route is registered with respect to the PE in which the new CE is accommodated. Information and route information having the same route target is transmitted. That is, in the present example, when the CE 60 is newly connected, the route information of the PE 20 is transmitted to the PE 30 in step S21.

  According to the processing shown in the above flowchart, it is possible to determine whether or not the filter information is registered in the RT filter DB 13 when route information is received, and to register it when it is not registered. Also, route information can be registered in the route information DB 13. Further, the route information can be advertised to PEs that permit the same route target. In addition, when a CE is newly accommodated in a PE, the registered route information having the same route target is transmitted, so the route information is advertised to all PEs regardless of the accommodation order. can do.

(D) Description of Modified Embodiment The above embodiment is an example, and it is needless to say that the present invention is not limited to the case described above. For example, in the embodiment shown in FIG. 1, three PEs 20 to 40 are connected to the RR 10, but two or four or more PEs may be connected.

  In the embodiment shown in FIG. 1, two types of VPNs, VPN A and VPN B, are provided. However, one type or three or more types of VPNs may be provided. Further, instead of accommodating one VPN in one PE, two or more types of VPNs may be accommodated. For example, the PE 20 may accommodate three types of VPN A, VPN C, and VPN D.

  In the above embodiment, the route information is registered in the route information DB 13 after the filter information is registered in the RT filter DB 14 in FIG. 7, but the filter information is registered after the route information is registered. It may be.

10 RR
11 reception processing unit 12 route information processing unit (acquisition means, part of transmission means)
13 Route information DB
14 RT filter DB (storage means)
15 Filter processing part (part of transmission means)
16 Transmission processing part (part of transmission means)
20-40 PE (BGP router)
50-70 CE

Claims (5)

In a route reflector device that transfers route information transmitted from a BGP router that performs routing by BGP to another BGP router,
When the route information transmitted from the BGP router is received because the VPN is added to the BGP router, the existing VPN is changed, or the existing VPN is deleted, the route information is changed to the route information. Acquisition means for acquiring the included route target information and the address information of the BGP router that transmitted the route information;
First storage means for constructing a first database by storing the route target information acquired by the acquisition means and the address information in association with each other;
Second storage means for constructing a second database by storing the route information;
When receiving the route information transmitted from the BGP router identifies the route target information included in the route information from the first database, the address information that is correlated with the route target information identified And transmitting means for transmitting the route information extracted from the second database ;
A route reflector device comprising: The first storage means includes
When the VPN is added, new information is registered in the first database . When the VPN is changed, the information registered in the first database is changed, and the VPN is deleted. In this case, the corresponding information is deleted from the first database ,
The second storage means includes
When the VPN is added, new information is registered in the second database. When the VPN is changed, the information registered in the second database is changed, and the VPN is deleted. 2. The route reflector device according to claim 1, wherein corresponding information is deleted from the second database .   The transmission means, when the VPN is added to the BGP router, transmits the route information of the existing BGP router to the BGP router to which the VPN is added. 2. The route reflector device according to 2. In a route control method for transferring route information transmitted from a BGP router that performs routing by BGP to another BGP router,
When the route information transmitted from the BGP router is received because the VPN is added to the BGP router, the existing VPN is changed, or the existing VPN is deleted, the route information is changed to the route information. An acquisition step for acquiring the included route target information and the address information of the BGP router that transmitted the route information;
A first storage step of constructing a first database by associating and storing the route target information acquired in the acquisition step and the address information in a first storage means;
A second storage step of constructing a second database by storing the route information in a second storage means;
When receiving the route information transmitted from the BGP router identifies the route target information included in the route information from the first database, the address information that is correlated with the route target information identified And transmitting the route information extracted from the second database ,
A path control method comprising: In a network system having a plurality of BGP routers that perform routing by BGP and a route reflector device that transfers route information transmitted from the BGP router to another BGP router,
The route reflector is
When the route information transmitted from the BGP router is received because the VPN is added to the BGP router, the existing VPN is changed, or the existing VPN is deleted, the route information is changed to the route information. Acquisition means for acquiring the included route target information and the address information of the BGP router that transmitted the route information;
First storage means for constructing a first database by storing the route target information acquired by the acquisition means and the address information in association with each other;
Second storage means for constructing a second database by storing the route information;
When receiving the route information transmitted from the BGP router identifies the route target information included in the route information from the first database, the address information that is correlated with the route target information identified And transmitting means for transmitting the route information extracted from the second database ;
A network system comprising:

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