KR101209215B1 - Method for changing route distinguisher in network - Google Patents

Abstract

The present invention relates to a method of changing a path distinguisher of a network. The method of changing a path discriminator of a network according to an embodiment of the present invention includes a method of changing a path discriminator of a network. In a network including a connection router, a step in which a predetermined subscriber network connection router changes a path separator of the corresponding subscriber network, determines whether the other subscriber network connection router supports a path discriminator change function, and the other party joins. If the self-connecting router supports the path distinguisher change function, transmitting the path distinguisher change message to the other subscriber network connection router. Thereby, the dynamic change of the path identifier RD used to distinguish the VPN path information in the BGP / MPLS VPN network is possible.

Network, path, identifier, change, message

Description

{Method for changing route distinguisher in network}

The present invention relates to a method for changing a path distinguisher of a network, and more particularly, to a method for changing a dynamic path distinguisher in a BGP / MPLS VPN network.

The present invention is derived from a study conducted as part of the IT growth engine technology development project of the Ministry of Knowledge Economy and the Ministry of Information and Communication Research and Development. Support router technology development].

MPLS (Multi Protocol Label Switching) is a technology that improves the performance of IP network by routing Internet Protocol (IP) packets only during network input and output and performing high-speed switching using labels in the center of the network. A Label Switched Path (LSP), which is a logical channel, is set in the IP network to operate as a connected type.

MPLS is a transport mechanism designed to provide IP flexibility and scalability while providing Asynchronous Transfer Mode (ATM) or Quality of Service (QoS) of frame relay. It has an easy structure to provide VoIp (Voice over IP) '/' Video over IP '.

Among them, MPLS Multi Protocol Label Switching Virtual Private Network (VPN) performs the decommissioning of user groups by selectively distributing routing information. Definitions, methods of handling, and network operational procedures and policies are described.

However, there is no suggestion of how to change the path delimiter (RD) of the VPN group, and simply change the path delimiter (RD) of the VPN group in the subscriber network connection router (PE router). In this case, since the other PE router recognizes the creation of a new VPN group, there is a problem in that information about a VPN group that is separate from a VPN group having an existing path distinguisher (RD) is constructed.

It is an object of the present invention to provide a method for handling the dynamic change of a path identifier (RD) used to distinguish VPN path information in a BGP / MPLS VPN network.

According to an aspect of the present invention, there is provided a method for changing a path discriminator of a network, in a network including a plurality of subscriber network connection routers connected to a plurality of subscriber networks. Changing the path discriminator of the own network; determining whether the other subscriber network connection router supports the path discriminator change function; and if the other subscriber network connection router supports the path discriminator change function, And transmitting a path distinguisher change message to the subscriber network connection router.

According to an embodiment of the present invention, when the other subscriber network connection router supports the path discriminator change function, the VPN subscriber information is distinguished from the BGP / MPLS VPN network by transmitting a path identifier change message to the other subscriber network connection router. This allows for dynamic modification of the path identifier (RD) used to Accordingly, the VPN group information can be prevented from being duplicated in the other subscriber network connection router and the operability of the VPN network can be improved.

Hereinafter, with reference to the drawings will be described the present invention in more detail.

FIG. 1 is a diagram illustrating a configuration of a BGP / MPLS VPN network according to the present invention, FIG. 2 is a diagram illustrating a configuration of a BGP open message, and FIG. 3 is a diagram illustrating a configuration of a BGP update message.

Referring to the drawings, the BGP / MPLS VPN network provides a virtual private network (VPN) service to users connected to the public network using Border Gateway Protocol (BGP) technology and Multi-Protocol Label Switching (MPLS) technology. To provide a network.

As shown in the figure, a router that is directly connected to a subscriber network in a BGP / MPLS VPN network is called a subscriber network connection router (PE (Provider Edge Router), hereinafter called a PE router), and is used in a subscriber network for a VPN service. A router connected to the PE router is called a public network router (CE (Customer Edge) router, hereinafter referred to as CE router).

In order to perform packet transmission in such a BGP / MPLS VPN network, first, each PE router (PE1, PE2) establishes an iBGP session with the other PE routers (PE2, PE1) and then sends them through a BGP UPDATE message. Exchange route information for this serving VPN group.

Here, the BGP of each PE router (PE1, PE2) supports a capability advertisement function that informs the other PE routers (PE2, PE1) of the functions that can be supported by each PE router, and each PE router supports multiprotocol extension. (Multiprotocol Extension), BGP Extended Communities Attribute, and BGP Route Update (ROUTE REFRESH) message processing.

The operation of the BGP / MPLS VPN network is briefly described below.

First, when a TCP (Transmission Control Protocol) connection for establishing an iBGP session between each PE (PE1, PE2) is completed, an iBGP session is established through BGP open message exchange as shown in FIG. The router adds a code, length, and value for each function supported by the local station to the option parameter of the BGP open message, thereby transmitting the corresponding BGP such as a multiprotocol extension function or a path update function. Informs the peer PE router of the function it can handle.

On the other hand, when the BGP open message is received from the peer PE router through the BGP open message exchange, it checks the option parameter of the received BGP open message to determine whether it supports all the functions included in the option parameter of the BGP open message.

If the judgment result does not support all the functions included in the option parameter of the received BGP open message, the BPE NOTIFICATION message is sent to inform the other PE router that there is an unsupported function, and the iBGP session setup is terminated. .

On the other hand, if all of the functions included in the option parameter of the BGP open message received as a result of the determination, and transmits the (KEEPALIVE) message to the peer PE router.

After receiving the BGP keep-alive message from the peer PE router, and iBGP session establishment with the peer PE router is completed normally, each PE router routes to all VPN groups serviced by each PE router through the update message of FIG. Exchange information with peer PE router.

As described above, each PE router that exchanges route information for a VPN group through a BGP update message is a VPN Routing and Forwarding used for packet transmission to each VPN group based on the route information for the exchanged VPN group. ) Tables are created and managed, and the VRF table is configured separately from the general IP routing table, and is managed only in the PE router serving the VPN group.

Here, as shown in Fig. 1, the PE router distinguishes the route information from the subscriber site by using a Route Distinguisher (RD) to distinguish the route information from the subscriber site from the route information of the public IP network.

For example, if a CE router is added to a VPN group to receive VPN services in a specific VPN group, it assigns a path identifier (RD) at the PE router to distinguish route information from that CE router, It is managed independently by the VPN group provided by the router.

In addition, the peer PE router distinguishes relevant VPN groups based on the route identifier (RD) of the VPN route information received through the BGP update message, and if the route identifier (RD) is different, recognizes it as a separate VPN group. do.

Meanwhile, in the embodiment of the present invention, when the path identifier RD of the VPN group is changed, the path identifier RD is dynamically changed. This will be described later with reference to FIG.

4 is a flowchart showing a path distinguisher change function notification procedure in accordance with the present invention.

Referring to the drawings, first, a TCP (Transmission Control Protocol) connection for establishing an iBGP session between PE routers PE1 and PE2 is established through an operator's input (S400). In order to exchange VPN route information between PE routers in a BGP / MPLS VPN network, an iBGP session must be established between each PE router.

Next, when a TCP connection is established successfully as a result of the TCP connection setting in operation 400 (S400), the PE router notifies the counterpart PE router of the function of the BGP open message to inform the BGP function supported by the local station (S405). . In particular, the option parameter in the BGP open message adds a path identifier (RD) change option parameter.

Message format and procedure related to BGP feature notification is operated in accordance with RFC2842 “Capabilities Advertisement with BGP-4” established by Internet Engineering Task Force (IETF). According to this standard, feature notification option parameters are code, length and length. ), And Value.

On the other hand, if the code value of the function notification option parameter is standardized, the value assigned from the Internet Assigned Number Authority (IANA) should be used. If it is not standardized, private assignment code values 128 to 255 may be used. That is, a code value of a path identifier (RD) change option parameter can be newly assigned.

Next, the BGP open message is transmitted to the peer PE router (S410).

Next, the BGP open message from the peer PE router is received (S415).

Through this process, it is determined whether the BGP of the corresponding PE router supports all the functions supported by the BGP of the other PE router (S420).

If the determination result is supported, the BGP connection maintenance message is transmitted to the peer PE router (S425). If the determination result is not supported, a code value of an unsupported function is inserted into the error sub code of the BGP notification message to the peer PE router. After the transmission (S430), the iBGP session is stopped (S455).

On the other hand, in step 425, it is determined whether a BGP connection maintenance message is received from the peer PE router in response to the BGP connection maintenance message transmission (S435). The iBGP session is set by setting the RD change function to Enable (440). If the BGP notification message is received as a result of the determination, it is determined whether the error sub code value in the message is the RD change function code value. It is determined (S445).

As a result of the determination in step 445, when the error sub code value is the path discriminator change function code value, the path discriminator change function is set to Disable and the iBGP session is reestablished (S450). If the error sub code value is not the path distinguisher (RD) change function code value, the iBGP session is suspended (S455).

As described above, when iBGP session establishment between PE routers for providing BGP / MPLS VPN service is normally established, each PE router (PE1, PE2) uses all of the services serviced by each PE router using the BGP update message of FIG. Exchange route information for a VPN group.

5 is a flowchart illustrating a method of changing a path discriminator according to an embodiment of the present invention, FIG. 6 is a diagram illustrating a configuration of a BGP path identifier change message of FIG. 5, and FIG. 7 is a BGP path update message of FIG. 5. Figure showing the configuration of the.

Referring to the drawings, the path distinguisher changing method of FIG. 5 is performed on the premise of exchanging path information on a mode group served by each PE router of FIG.

First, the PE router performs a task of changing the path identifier RD of related VPN group information in the corresponding PE router (S505). This change is performed when the operator enters a path distinguisher (RD) change.

Next, it is determined whether the peer PE router supports the path distinguisher (RD) change function (S510). This is to change the path information of the related VPN group previously transmitted to the peer PE router.

As a result of the determination in step 510 (S510), when the peer PE router supports the path distinguisher (RD) change function, the BGP path distinguisher change message is transmitted to the peer PE router (S515).

6 shows a configuration of a BGP path distinguisher change message. The size of the path identifier (RD) value in the BGP path identifier change message may vary. In addition, the route identifier (RD) value in the BGP route identifier change message may include an old route distinduisher and a new route distinduisher. Accordingly, the path distinguisher change can be clearly performed.

On the other hand, if the peer PE router does not support the path distinguisher (RD) change function, and transmits the existing BGP update message once to delete the route information for the VPN group (S520). The BGP update message may be as shown in FIG. 3. That is, the route information for the corresponding VPN group can be deleted using the option parameter information in the BGP update message.

Thereafter, it is again determined whether a BGP notification message including an update message error is received from the peer PE router (S530). If there is no error as a result of the determination, the VPN group is newly connected to the peer PE by using the existing BGP update message. Add route information for (S545). The BGP update message may be as shown in FIG. 3. That is, the route information for the corresponding VPN group can be added by using the option parameter information in the BGP update message.

If there is an error as a result of the determination in step 530 (S530), the iBGP session is stopped (S540).

On the other hand, in step 525 (S525), if there is no error as a result of the determination, a BGP path update message is transmitted to the counterpart PE router (S535). If there is an error as a result of determination, the iBGP session is suspended (S540). The BGP path update message may be as shown in FIG. 7.

On the other hand, the present invention can also be embodied as computer readable codes on a computer readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and may be implemented in the form of a carrier wave (for example, transmission via the Internet) . The computer readable recording medium may also be distributed over a networked computer system so that computer readable code can be stored and executed in a distributed manner.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the invention as defined by the appended claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

1 is a diagram showing the configuration of a BGP / MPLS VPN network according to the present invention by way of example.

2 is a diagram illustrating a configuration of a BGP open message.

3 is a diagram illustrating a configuration of a BGP update message.

4 is a flowchart showing a path distinguisher change function notification procedure in accordance with the present invention.

5 is a flowchart illustrating a method of changing a path separator according to an embodiment of the present invention.

FIG. 6 is a diagram illustrating a configuration of a BGP path distinguisher change message of FIG. 5.

FIG. 7 is a diagram illustrating a configuration of a BGP path update message of FIG. 5.

Claims (9)

A method of changing a path discriminator in a network including a plurality of subscriber network connection routers connected to a plurality of subscriber networks, Changing, by a predetermined subscriber network connection router, a path discriminator of a corresponding subscriber network; Determining whether the other subscriber network connection router supports a path discriminator change function; And And transmitting a path discriminator change message to the counterpart subscriber network connection router when the counterpart subscriber network connection router supports a path discriminator change function. The method of claim 1, The path distinguisher change message, And a path distinguisher before the change of the corresponding subscriber network, and the changed path discriminator. The method of claim 1, If a notification message including a path discriminator change error is not received from the other subscriber network connection router, transmitting a path update message to the other subscriber network connection router; How to change the separator. The method of claim 1, When receiving a notification message including a path discriminator change error from the other subscriber network connection router, stopping the connection between the predetermined subscriber network connection router and the other subscriber network connection router; How to change the path separator of a network. The method of claim 1, If the counterpart subscriber network connection router does not support a path distinguisher change function, transmitting an update message for deleting the path information of the corresponding subscriber network to the counterpart subscriber network connection router. How to change the path separator of a network. The method of claim 5, Terminating a session with the counterpart subscriber network connection router when receiving a notification message including an error about an update message for deleting the route information. . The method of claim 5, If the notification message including an error about the update message for deleting the route information is not received, transmitting an update message for changing the route information of the corresponding subscriber network to the counterpart subscriber network connection router; How to change the path identifier of the network, characterized in that. The method of claim 1, The determining step and the transmitting step, And performing a connection maintenance message from the counterpart subscriber network connection router. The method of claim 1, And said network comprises a multi-protocol label switching network.

Images