KR100519166B1 - Method for Echo Requesting in ATM MPLS VPN Network - Google Patents

Abstract

The present invention relates to an echo request method in an ATM MPLS VPN network capable of checking whether a packet arrives at a subscriber side directly connected to a peer PE router using a private address of a customer edge (CE).

In the conventional ATM MPLS VPN network, before providing VPN service to subscribers, the CE router, which is directly connected to the peer PE router, does not provide a function to check whether packet arrival is normally performed. There is a problem in that it continues to deliver packets.

In the present invention, when the private address and VPN group information of the CE router inputted from the operator in the ingress PE router is transferred to the egress PE router to which the CE router is directly connected, the egress PE router receives the ingress PE router. By pinging the CE router based on the information, it is possible to check whether the packet can reach the CE router directly connected to the peer PE router using the private address of the CE router.

Description

Method for echo request in ATM MPLS VPN network {Method for Echo Requesting in ATM MPLS VPN Network}

The present invention relates to an echo request method in an Asynchronous Transfer Mode (ATM) Multi Protocol Label Switching (MPLS) virtual private network (VPN) network, and in particular, directly connected to a peer PE router using a private address of a customer edge (CE). The present invention relates to an echo request method in an ATM MPLS VPN network capable of confirming whether a packet reaches a subscriber.

In general, an Asynchronous Transfer Mode (ATM) Multi Protocol Label Switching (MPLS) Virtual Private Network (VPN) is a network providing VPN services to users connected to a public network, and FIG. 1 illustrates a typical ATM MPLS VPN network. It is shown.

The router directly connected to the subscriber network in the ATM MPLS VPN network of FIG. 1 is called a provider edge router (PE1, PE2), and a router directly connected to the PE routers (PE1, PE2) in the subscriber network for VPN service. It is called a CE (Customer Edge) router (CE1, CE2, CE3, CE4).

As described above, the PE routers PE1 and PE2 establish an internal border gateway protocol (iBGP) session connection with each other and exchange routing information of subscriber networks directly connected to them, and the PEs received routing information through the iBGP session. The routers PE1 and PE2 transmit the received routing information to the site through the CE routers CE1, CE2, CE3, and CE4.

The CE routers CE1, CE2, CE3, and CE4 directly connected to the PE routers PE1 and PE2 are assigned a private address from the PE routers PE1 and PE2 to the corresponding CE routers CE1, CE2, CE3, and CE4. It must have a built-in interface. In this way, the assigned interface is configured for the VPN when configuring the subscriber-side IPOA interface, so that the RD (Route Distinguisher) of the VPN group to which the CE router connected to the interface belongs is associated with each other.

As a result, it is possible to look up a forwarding table for a VPN in order to transmit a packet entering the interface.

As described above, after each PE router (PE1, PE2) exchanges the routing information for the subscriber network managed in the home country with the peer PE router (PE2, PE1) that is connected end-to-end through an iBGP session, subscribers When the packet is received from the network, the packet is received from the subscriber network based on the routing information exchanged with each other.

However, in the conventional ATM MPLS VPN network, before providing a VPN service to a subscriber, a function for checking whether packet arrival is normally performed to a CE router directly connected to a counterpart PE router is not provided.

As a result, there is a problem in that packets continue to be delivered to the CE router in which packet arrival is not normally performed.

The present invention has been made to solve the above-mentioned problem, and when the ingress PE router transfers the private address and VPN group information of the CE router received from the operator to the egres PE router directly connected to the CE router, egres The PE router pings the CE router based on the information received from the ingress PE router, so that the packet can reach the CE router directly connected to the peer PE router using the CE router's private address. The purpose of the present invention is to provide an echo request method in ATM MPLS VPN network.

A feature of the present invention for achieving the above object is, in the echo request method in the AMT MPV VPN network, the private address of the CE router to check the reachability from the operator through the MMI in the Ingress PE routers; Receiving VPN group information to which the CE router belongs; Retrieving an RD and VRF table using the received VPN group information in the ingress PE router and finding a next hop by searching the retrieved VRF table with the private address; In the ingress PE router, the next hop is used as a destination address, and an IP header including a VPN recorded in a protocol type field is added to the data part including the private address and VPN group information. The packet is generated through an ATM MPLS VPN network. Transmitting to the Grass PE router; In the egress PE router, the packet received from the ingress PE router is analyzed to determine the reachability of the CE router. If the packet is a packet for which the CE router is to be reached, the VPN group information and the private address included in the packet are used. Generating an ICMP reachable echo request packet; At the egress PE router, looking up the ICMP reachable echo request packet in a VPN forwarding table and transmitting it to the CE router; Whether or not packet forwarding to the CE router is possible or not depending on whether an egress PE router receives an ICMP reachability echo response packet, which is a response packet to the ICMP reachability echo request packet, from the CE router. Judging process; The egress PE router generates a response packet including the determination result, adds an IP header including the address of the ingress PE router as a destination address and records a VPN in a protocol type field, and then adds the packet through the ATM MPLS VPN network. Transmitting to an ingress PE router; And analyzing, by the ingress PE router, the packet received from the egress PE router and reporting the reachability of the CE router to the operator.

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Hereinafter, an echo request method in an ATM MPLS VPN network according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 is a road showing a configuration of a PE router to which an echo request method according to the present invention is applied, a VPN controller 10, an IP unit 20, a SI (subnet interface) unit 30, and a forwarding engine (FE). A portion 40 is provided.

In such a configuration, the VPN controller 10 performs an interface with the SI unit 30 to process the echo request message for the VPN, and sends an IP unit 20 to send a message to the other end PE router that is connected end-to-end. Interface). The RD (Route Distinguisher) and the VRF table are searched based on the private address of the CE router to check the reachability input from the operator and the VPN group information to which the CE router belongs. NEXTHOP) is applied to the IP unit 20. If the packet is the packet to be determined as a result of analyzing the data of the packet received from the IP unit 20, the RD and the private address included in the data unit of the packet are After generating the ICMP (Internet Control Message Protocol) reachability direction request packet, and sends down to the FE unit 40 through the SI unit (30).

The IP unit 20 creates an IP header obtained by using the next hop authorized by the VPN control unit 10 as a destination address, writes a VPN in the protocol type field, adds it to the data unit, and applies the SI unit 30 to the SI unit 30. 30, the IP header of the authorized packet is removed, and if the protocol type field is VPN, the packet is applied to the VPN controller 10.

The SI unit 30 transmits the packet authorized from the IP unit 20 to the ATM MPLS VPN network through the FE unit 40.

The packet authorized from the FE unit 40 is transmitted to the ATM MPLS VPN network, and the ICMP reachability echo request packet authorized from the VPN control unit 10 through the SI unit 30 is looked up in the VPN forwarding table to the corresponding CE router. send.

3 is a diagram illustrating an echo request method in an ATM MPLS VPN network according to the present invention.

First, the Ingress PE router PE1 receives a private address of a CE router and a VPN group information belonging to the CE router to check reachability from an operator through an MMI (Man Machine Interface) (1). S10).

In step S10, the VPN control unit PE1-10 of the ingress PE router PE1 that receives the private address of the CE router and the VPN group information to which the CE router belongs, receives the private address of the CE router to check reachability from the operator. Search the RD and VRF table by using the VPN group information received in S10, search the found VRF table by the private address of the CE router received in the above process S10, find out the next hop, and then go to the IP unit (PE1-20). It is applied (S12).

The IP unit PE1-20, which has received the next hop from the VPN controller PE1-10, creates an IP header that records the VPN in the protocol type field by using the authorized next hop as a destination address, and checks the reachability. After adding to the data portion consisting of the private address of the router and the VPN group information to which the CE router belongs, it is applied to the SI unit PE1-30 (S14).

In step S14, the SI unit PE1-30, which receives the packet from the IP unit PE1-20, transmits the authorized packet to the Egress PE router PE2 through the FE unit PE1-40. (S16, S18).

The packet transmitted from the ingress PE router (PE1) through the above process S18 is transmitted to the egress PE router (PE2) through the ATM MPLS VPN network. The FE unit (PE2-40) and the SI unit (PE2-30) IP header (PE2-20) of the egress PE router (PE2) that received the packet transmitted from the ingress PE router (PE1) through) analyzes the IP header of the received packet, and thus the destination is itself. Since the VPN is recorded in the protocol type field, the data unit is applied to the VPN control unit PE2-10 (S20, S22, S24).

Since the VPN control unit PE2-10 receiving the data unit from the IP unit PE2-20 in step S24 is intended to determine the reachability of the CE router, the intent PE router PE1 intends to determine the reachability of the CE router. After generating the ICMP reachability echo request packet (PING packet) using the VPN group information and the private address included in the data part authorized from the PE2-20), the SI part (PE2) using IPC (Inter Process Communication) -30) down to the FE part (PE2-40) (S26, S28).

The FE unit PE2-40 receiving the ICMP reachability echo request packet transmits the ICMP reachability echo request packet to the corresponding CE router by looking up the VPN forwarding table (S30). The ICMP reachable echo request packet transmitted to the CE router at (PE2) is received by the CE router. If the corresponding CE router receiving the ICMP reachable echo request packet is in normal operation, the ICMP reachable echo request packet is received. If the corresponding CE router receiving and transmitting the response packet to the egress PE router (PE2) and receiving the ICMP reachability echo request packet does not operate, it does not receive the ICMP reachability echo request packet and returns the response packet. It will not be able to send to the PE router (PE2).

That is, when the CE router operates normally, the ICMP reachability echo request packet transmitted in the above step S30 is received through the FE unit CE-40 and the SI unit CE-30. The SI unit CE-30 of the CE router that receives the ICMP reachability echo request packet from the router PE2 applies the received packet to the IP unit CE-20 (S32 and S34).

In the IP unit CE-20 that receives the ICMP reachability echo request packet from the SI unit CE-30, the ICMP reachability echo response packet is generated by the ICMP processing function since the authorized packet is an ICMP reachability echo request packet. When the IP header is generated, the IP header is replaced with the destination field and the source field. The IP header is sent to the ICMP reachability echo response packet, and is then sent down to the FE unit CE-40 through the SI unit CE-30.

The FE unit CE-40 that receives the ICMP reachability echo response packet transmits the received ICMP reachability echo response packet to the egress PE router PE2 (S40). An egress PE router (PE2) that sent an ICMP reachability echo request packet to a CE router waits for an ICMP reachability echo response packet, which is a response packet to the ICMP reachability echo request packet, from the CE router. Does not operate or fails to receive a response packet for the ICMP reachability echo request packet from the CE router due to an error occurring in the path, the packet forwarding from the VPN controller PE2-10 to the CE router is disabled. After generating a response packet having a data portion including information that is not possible, the address of the ingress PE router PE1 connected to the end-to-end is passed to the IP portion PE2-20. The IP unit PE2-20 uses the address passed from the VPN control unit PE2-10 as the destination, creates an IP header in which the VPN is written in the protocol type field, adds it to the response packet, and then adds the response packet to the SI unit PE2-30. And the ingress PE router PE1 through the FE unit PE2-40.

On the other hand, the egress PE router (PE2) transmitting the ICMP reachability echo request packet to the CE router through the above process S30 is transmitted from the CE router through the FE unit (PE2-40) and SI unit (PE2-30). When receiving an ICMP reachability echo response packet, the IP part PE2-20 of the egress PE router PE2 analyzes the IP header of the received packet and removes the IP header if the destination is itself. Apply to VPN control unit PE2-10 (S42, S44, S46).

Since the VPN controller PE2-10 receives the ICMP reachability echo response packet from the IP unit PE2-20 in step S46, the IC router reaches the CE router. It writes that transmission is possible and transfers the address of the ingress PE router PE1 connected to the end-to-end to the IP unit PE2-20 (S48).

The IP unit PE2-20, which has received the address of the ingress PE router PE1 connected from the VPN control unit PE2-10 to the end-to-end connection, uses the received address as the destination address and enters the VPN in the protocol type field. An IP header is generated, added to the ICMP reachability echo response packet, and applied to the SI unit PE2-30 (S50).

In step S50, the SI unit PE2-30 receiving the reachable echo response packet from the IP unit PE2-20 receives the received reachable echo response packet through the FE unit PE2-40. Transfer to PE1 (S52, S54).

Packets transmitted from the egress PE router (PE2) are transmitted to the ingress PE router (PE1) through the ATM MPLS VPN network, and the egress PE through the FE unit (PE1-40) and the SI unit (PE1-30). The IP part PE1-20 of the ingress PE router PE1 receiving the packet transmitted from the router PE2 removes the IP header because the destination address is itself as a result of analyzing the IP header of the received packet. Since the VPN is recorded in the type field, the data unit of the received packet is applied to the VPN controller PE1-10 (S56, S58, and S60).

In step S60, the VPN control unit PE1-10, which receives the data unit from the IP unit PE1-20, checks the contents of the data unit received from the egress PE router PE2, and sends the data unit to the CE router. Report whether or not packet delivery is possible to the operator through the MMI (1) (S62).

The echo request method in the ATM MPLS VPN network of the present invention is not limited to the above-described embodiments, and may be variously modified and implemented within the range allowed by the technical idea of the present invention.

According to the echo request method in the ATM MPLS VPN network of the present invention as described above, the egress PE router to which the CE router directly connects the private address and VPN group information of the CE router inputted from the operator in the ingress PE router. In this case, the egress PE router pings the CE router based on the information received from the ingress PE router, thereby directly connecting to the other PE router using the CE router's private address. It is possible to confirm whether or not the packet can reach the side.

1 is a diagram showing the configuration of a typical ATM MPLS VPN network by way of example.

2 is a diagram illustrating a configuration of a PE router to which an echo request method according to the present invention is applied;

3 is a diagram illustrating an echo request method in an ATM MPLS VPN network according to the present invention;

*** Explanation of symbols for the main parts of the drawing ***

MMI, 10, PE1-10, PE2-10. VPN control unit,

20, PE1-20, PE2-20, CE-20. IP section, 30, PE1-30, PE2-30, CE-30. SI department,

40, PE1-40, PE2-40, CE-40. FE part

Claims (4)

In the method of requesting echo in AMT MP VNP network, Receiving a private address of a CE router and a VPN group information belonging to the CE router to check reachability from an operator through an MMI in an ingress PE router; Retrieving an RD and VRF table using the received VPN group information in the ingress PE router and finding a next hop by searching the retrieved VRF table with the private address; In the ingress PE router, the next hop is used as a destination address, and an IP header including a VPN recorded in a protocol type field is added to the data part including the private address and VPN group information. The packet is generated through an ATM MPLS VPN network. Transmitting to the Grass PE router; In the egress PE router, the packet received from the ingress PE router is analyzed to determine the reachability of the CE router. If the packet is a packet for which the CE router is to be reached, the VPN group information and the private address included in the packet are used. Generating an ICMP reachable echo request packet; At the egress PE router, looking up the ICMP reachable echo request packet in a VPN forwarding table and transmitting it to the CE router; Whether or not packet forwarding to the CE router is possible or not depending on whether an egress PE router receives an ICMP reachability echo response packet, which is a response packet to the ICMP reachability echo request packet, from the CE router. Judging process; The egress PE router generates a response packet including the determination result, adds an IP header including the address of the ingress PE router as a destination address and records a VPN in a protocol type field, and then adds the packet through the ATM MPLS VPN network. Transmitting to an ingress PE router; Echo request in the ATM MP VPS network comprising the step of analyzing the packet received from the egress PE router in the ingress PE router to report the reachability of the CE router to the operator Way. delete delete delete