KR100772190B1 - MPLS Interworking System and method using Pre-assigned Label Value - Google Patents

Abstract

The present invention relates to an MPLS interworking system and a method using a pre-allocated label value, and assigns a label value indicating what kind of two-layer protocol the information conveyed by the MPLS packet is, and then inserts it into the packet to exit. If the label value in the received packet header is a label value indicating a layer 2 protocol, the exit LSR deletes the label value without referring to the label table and then the layer 1 corresponding to the label value. Since the layer protocol processing unit delivers a packet to a next node, the present invention relates to an MPLS interworking system and a method capable of high-speed packet transmission by shortening a label table reference time required for packet transmission.

MPLS, pre-allocated label, LSR, packet head. Layer 1 and Layer 2 protocols

Description

MPLS Interworking System and method using Pre-assigned Label Value}

1 is a diagram schematically showing a system implementing conventional MPLS.

2 is a block diagram illustrating an MPLS interworking system using a pre-assigned label value according to an embodiment of the present invention.

3 is a diagram illustrating a process of performing MPLS interworking using a pre-allocation label value in an exit LSR according to another embodiment of the present invention.

FIG. 4 is a diagram illustrating an interworking method of an MPLS interworking system using the pre-allocation label value shown in FIG. 2.

<Description of main parts of the drawings>

Inlet LSR: 800 Outlet LSR: 700

Relay LSR: 600 Ethernet: 100, 150

IPv4: 200, 250 ATM: 300, 350

The present invention relates to an MPLS interworking system and a method using a pre-allocated label value, and more particularly, to a MPLS interworking system and a method capable of high-speed packet transmission by reducing the label table reference time required for packet transmission. .

The emergence of multimedia services such as voice and video and various real-time applications places high demands on the Internet and high bandwidths on the Internet. Considering this situation of the Internet, Multi-Protocol Label Switching (MPLS) technology is a movement to evolve into a next-generation Internet network capable of providing high speed and high quality of service (QoS). This was developed. MPLS technology combines ATM's high-speed multi-service switching function based on the existing routing method and delivers IP packets. It aims to provide various additional services along with high-speed data transmission in a large network.

MPLS is a kind of third layer switch technology that uses a second layer switching technology such as ATM or frame relay to speed packet forwarding, and connects a routing function of the third layer to provide network scalability. In MPLS, a label exchange method of transmitting a packet based on a short and fixed length label is used. Therefore, in MPLS, IP packet header processing required for transmitting IP packets to a destination is performed only once when an IP packet enters an MPLS network without having to be performed in every Label Switching Router (LSR).

Hereinafter, the MPLS technology will be briefly described with reference to the accompanying drawings.

As shown in FIG. 1, in a system implementing MPLS, a label switching router has a large ingress LSR 10-1, a transit LSR 20-1, 30-1, and an exit depending on its role. (Egress) can be distinguished by the LSR 40-1. The incoming LSR 10-1 is located at the point where the unlabeled IP packet first arrives in the MPLS network, and refers to the packet header information, that is, the destination address or the destination network address, and inserts a corresponding label into the packet accordingly. A packet is transmitted to the relay LSR 20-1.

The relay LSRs 20-1 and 30-1 are LSRs which perform a switching operation at high speed only by the label information upon receiving a packet including a label. The label forwarding is composed of rows consisting of elements of an input label, an output label, and an output port. It has a table called Label Forwarding Information Base (LFIB). The exit LSR 40-1 has an LFIB as an LSR that operates to transmit a packet to a general router by removing a label and checking a packet's destination address or network number when a packet including a label is received.

In order to perform fast switching with reference to only a label from the incoming LSR to the exit LSR via the relay LSRs, the above-mentioned LSRs must be labeled and the table information must be appropriately set.

The packet arriving at the conventional exit LSR is unlabeled and once exits the MPLS network as an IP packet. However, the actual label elimination knows that the next LSR in the Penultimate LSR (LSR) just before the exit LSR is known as the exit LSR. To be assigned. This is to reduce the load on the exit LSR by indicating that the exit LSR does not need to refer to the label to forward MPLS packets to the IPv4 or IPv6 router. This feature is called PHP (Penultimate Hop Popping) and it is basically applied in general MPLS network.

Recently, MPLS has been widely used as a technology for interworking and transmitting data of Layer 1 (L1) protocols such as TDM and Layer 2 (L2) protocols such as Ethernet and ATM. Therefore, there is a need for applying the above-described PHP technology to the MPLS interworking technology in order to maintain high speed packet delivery, which is the biggest advantage of MPLS.

An object of the present invention is to provide an MPLS interworking technique capable of delivering data packets of L1 and L2 protocols at high speed.

Another object of the present invention is to provide an MPLS interworking method capable of high-speed packet transmission by reducing the number and time of referencing a label table required for packet transmission in an exit LSR.

As a preferred embodiment of the present invention for achieving the above object, a fast packet forwarding method using a pre-assigned label in the relay label switching router immediately before the exit label switching router,

A pre-assignment label generation step of setting the output label to the label value indicating the type of the L2 protocol the MPLS packet transfers the input label of the received MPLS packet to immediately before the relay LSR;

Removing an input label inserted in an MPLS packet received from an external source,

Inserting an output label value indicating the type of L1 or L2 protocol delivered by the received packet into the packet;

And sending the packet with the pre-assigned label inserted to an exit label switching router.

In addition, according to another preferred embodiment of the present invention, a fast packet forwarding method using a pre-assigned label in the exit label switching router,

A pre-assignment label setting step of setting different labels according to the frame type of the L1 or L2 protocol constituting the deliverable packet;

If a packet is transmitted from the outside, confirming whether a label inserted in the delivered packet matches one of the pre-allocated labels;

Deleting the label, obtaining information about a network to which the packet is to be delivered from a pre-assigned label that matches the label, and then forwarding the information to a destination node corresponding to the network.

In addition, the high-speed packet delivery method using a pre-assigned label in the MPLS network according to the present invention for achieving the above object,

A pre-assignment label generation step of setting an output label with a label value indicating the type of L1 or L2 protocol carried by the MPLS packet;

Removing the label inserted in the packet received by the relay label switching router immediately before the exit label switching router from the outside;

Inserting an output label value indicating the type of L1 or L2 protocol delivered by the received packet into the packet;

Transmitting the packet with the pre-assigned label inserted to an exit label switching router;

Checking at an exit label switching router whether a label inserted in the forwarded packet matches one of the pre-allocated labels;

Deleting the label, obtaining information about a network to which the packet is to be delivered from a pre-assigned label that matches the label, and then forwarding the label to a destination node corresponding to the network.

In addition, a label switching router for delivering packets at high speed using a pre-assigned label in an MPLS network according to an embodiment of the present invention for achieving the above object,

An MPLS function unit for identifying a pre-allocated label inserted in the MPLS packet received from the relay label switching router and then deleting the label included in the header;

An MPLS interworking function unit for selecting an L1 or L2 protocol corresponding to the packet from which the header and the label are deleted by referring to a label deleted from the MPLS function unit; And,

And an L1 / L2 protocol processor for analyzing data information in the MPLS packet corresponding to the selected protocol and delivering the same to the next node.

In addition, in the MPLS network according to an embodiment of the present invention for achieving the above object, a system for delivering packets at high speed by using a pre-assigned label,

An incoming label switching router for generating an MPLS packet by inserting an MPLS label and header information into the packet to transmit a frame of an L1 or L2 protocol entering the MPLS network;

A relay label switching router which receives the MPLS packet from the incoming label switching router and inserts a pre-assigned label into the packet to transmit the MPLS packet; And,

Analyzes a label constituting the packet received from the relay label switching router, recognizes a network to which the packet is delivered using the analyzed label and the set label, and corresponds to a destination that recognizes the packet. It consists of an exit label switching router that forwards to the node.

According to the present invention, the MPLS interworking system using a pre-assigned label improves the performance of effectively delivering high-speed packets by reducing the number of label references and time required for packet transmission when the MPLS network interworks with various L1 / L2 protocol technologies. Has the advantage. In addition, the MPLS interworking system using the pre-allocated label of the present invention can know the L1 or L2 protocol of the frame delivered by the MPLS packet, and is configured in the same form as a general MPLS label table, and does not store additional information related to the label. Therefore, there is an advantage of effectively using the capacity of the MPLS interworking system.

Hereinafter, with reference to the accompanying drawings will be described in detail the operating principle of the preferred embodiment of the present invention. In the following description, when it is determined that the gist of the invention may be unnecessarily obscured, the detailed description thereof will be omitted. In addition, terms to be described below are terms defined in consideration of the functions of the present invention, and may vary according to the intention or custom of a user or an operator. Therefore, the definition should be made based on the contents throughout the specification.

2 is a block diagram schematically illustrating an MPLS interworking method using a pre-assigned label value according to an embodiment of the present invention. Hereinafter, an MPLS interworking method using a pre-assigned label value according to an embodiment of the present invention will be described in detail with reference to FIG. 2.

2, the system of the present invention includes an incoming LSR 800, two relay LSRs 600, and an exit LSR 700. In addition, the incoming LSR 800 is connected to the Ethernet 100, the IPv4 200, and the ATM 300, and the exit LSR 700 is also connected to the Ethernet 150, the IPv4 250, and the ATM 350. . Of course, it is apparent that other L1 or L2 protocols besides Ethernet, IPv4, and ATM may be connected with the incoming LSR 800 or the exit LSR 700. However, FIG. 2 shows only Ethernet, IPv4, and ATM for convenience of description.

Referring to FIG. 2, a label switching path is set between an incoming LSR 800 and an exit LSR 700 to exchange packets between two access networks. The Ethernet 100 transmits a packet to the Ethernet 150 via the incoming LSR 800, the relay LSRs 600, and the exit LSR 700 constituting the MPLS network 400. The IPv4 200 transmits the packet to the IPv4 250 via the incoming LSR 800, the relay LSRs 600, and the exit LSR 700 constituting the MPLS network 400. The ATM 300 transmits a packet to the ATM 350 via the incoming LSR 800, the relay LSRs 600, and the exit LSR 700 constituting the MPLS network 400.

Here, in the MPLS network according to the present invention, a fast packet forwarding method using a pre-assigned label is used in particular between the exit LSR 700 and the relay LSR 600 immediately before it.

First, when the MPLS packet is delivered to the relay LSR 600, the relay LSR 600 determines whether the next node to which the MPLS packet is to be forwarded is the exit LSR 700. 2, it can be seen that the relay LSR 600 is the LSR immediately before the exit LSR 700, and the next node is the exit LSR 700. Accordingly, the relay LSR 600 converts an input label constituting the header of the received MPLS packet into an output label indicating the L1 or L2 protocol.

Upon receipt of the MPLS packet with the pre-assigned label from the relay LSR 600, the exit LSR 700 first confirms the pre-assigned label and then deletes it. Then, based on the information recorded on the pre-assigned label, the information is transmitted to the corresponding L1 / L2 protocol node, that is, the Ethernet 150 or the ATM network 350.

3 is a view showing in detail the operation performed at the exit LSR in accordance with a preferred embodiment of the present invention. Hereinafter, an operation performed in the exit LSR according to an embodiment of the present invention will be described in detail with reference to FIG. 3.

According to FIG. 3, the exit LSR according to the present invention includes an MPLS function unit 450, an MPLS interworking function unit 500, and an L1 / L2 protocol processing unit 550.

First, the MPLS function 450 of the exit LSR, which has received the MPLS packet with the pre-assigned label inserted from the relay LSR 600, checks the pre-assigned label, deletes it, and then uses the MPLS interworking function 500 To pass). The MPLS interworking function unit 500 having received the packet from which the pre-allocation label has been deleted transmits the packet to a corresponding L1 / L2 protocol processor based on the information recorded in the pre-allocation table. The L1 / L2 protocol processor 550 of the exit LSR analyzes the data information in the MPLS packet and delivers the data information to the next node.

In FIG. 3, a label value 4 indicates an ATM, a label value 6 indicates a frame relay (FR), and a label value 7 indicates Ethernet.

At this time, in FIG. 3, the pre-allocation label shown in Table 1 is used as the pre-allocation label between the exit LSR and the immediately preceding relay LSR. The label value indicating the L1 or L2 protocol is not the final standardized value, but it is clear that the specific label value is used for the purpose of indicating the specific L1 or L2 protocol. This applies to all equipment and networks with MPLS technology.

[Table 1] Pre-allocation label for each L1 / L2 / L3 protocol

L1 / L2 / L3 Protocol Assigned label IPv4 Label0 IPv6 Label 2 ATM Label 4 FR Label6 Ethernet Label7

Although not shown in FIG. 3, the LSR immediately before the exit LSR allocates 0 as a pre-allocation label value if the MPLS packet to be delivered to the exit LSR is a packet to be delivered to the IPv4 network. The exit LSR assigns 2 as a pre-assigned label value if the received MPLS packet is to be transmitted to the IPv6 network and 4 as a preassigned label value if the received MPLS packet is to be transmitted to the ATM network. The exit LSR assigns 6 to the pre-assigned label value if the received MPLS packet is to be transmitted to the FR network, and assigns 7 to the pre-assigned label value to the forwarded MPLS packet to the Ethernet.

The L1 / L2 protocol processor of the exit LSR analyzes the packet received from the MPLS interworking function to determine the next node to forward. That is, when the header address of the received packet is related to IPv4, the exit LSR forwards the received packet to the IPv4 network. If the header address of the received packet is related to IPv6, the exit LSR forwards the received packet to the IPv6 network.

4 is a view for explaining in detail the interworking method of the MPLS interworking system using a pre-allocation label value. In this case, an additional label may be used between the MPLS label value and the Ethernet frame delivered by each LSR in FIG. 4 to more conveniently distinguish the Ethernet frame. Hereinafter, an interworking method using the MPLS interworking system according to an embodiment of the present invention will be described in detail with reference to FIG. 4.

In particular, FIG. 4 is a diagram illustrating a packet received from a network using an L1 or L2 protocol such as Ethernet among a plurality of networks by a high speed packet delivery method using a pre-assigned label in the MPLS network of the present invention to an L1 / L2 protocol network such as Ethernet An example is shown. Of course, the process of delivering the packet received from the network other than the Ethernet network to another network other than the Ethernet network is also performed by the same process as shown in FIG.

The interworking system of FIG. 4 includes an Ethernet switch 1 900, an incoming LSR 800, a relay LSR 600, an exit LSR 700, and an Ethernet switch 2 800. Obviously, the number of relay LSRs may vary according to user settings. In addition, the function of the incoming LSR 800 and the exit LSR 700 depends on the direction in which the packet is introduced. That is, when a packet is introduced from the exit LSR, the exit LSR performs the function of the incoming LSR, and the incoming LSR performs the function of the exit LSR.

The Ethernet switch 1 900 transmits the received Ethernet frame 10 to the incoming LSR 800 to send to the Ethernet switch 2 (850). When the incoming LSR 800 receives the Ethernet frame 10 from the Ethernet switch 1 900, the incoming LSR 800 inserts the MPLS label and header information into the Ethernet frame 10 to generate the MPLS packet 20. According to FIG. 4, the MPLS label assigned to the Ethernet frame received by the incoming LSR 800 is 100. However, the MPLS label assigned by the incoming LSR 800 to the received Ethernet frame is not fixed but variable.

The incoming LSR 800 transfers the generated MPLS packet 20 to the relay LSR. The relay LSR deletes the header information and the MPLS label of the received packet and adds the updated header information and the MPLS label. That is, according to FIG. 4, the relay LSR allocates 110 to the MPLS label.

The relay LSR forwards the reprocessed MPLS packet 30 to another relay LSR 600. The relay LSR 600 is a Penultimate LSR (LSR) immediately before the exit LSR 700 that recognizes that the next node to deliver the received MPLS packet 30 is the exit LSR 700. Accordingly, the relay LSR 600 inserts 7 into the packet as a pre-assigned label based on the pre-assigned label shown in Table 1 since the received MPLS packet 30 is an Ethernet frame, and then delivers the packet to the exit LSR 700.

Next, since the label inserted in the received MPLS packet 40 corresponds to one of the pre-assigned labels, the exit LSR 700 removes the MPLS label and header information, and then removes only the Ethernet frame 50 from the Ethernet switch 50. Forward to 850.

As described above, the packet is transmitted and received using the pre-assigned label to perform a fast switching operation.

Meanwhile, in the detailed description of the present invention, specific examples have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the equivalents of the claims as well as the appended claims.

As described above, in the MPLS interworking system using the pre-assigned label according to the present invention, when the MPLS network interworks with various L1 / L2 protocol technologies, the packet reference number and time required for packet transmission are reduced, thereby effectively delivering high-speed packets. There is the advantage of performance improvements that make it possible.

In addition, the MPLS interworking system using the pre-allocated label of the present invention contains the L1 or L2 protocol information of the data contained in the MPLS packet, is configured in the same form as the general MPLS label table, and stores additional information related to the label in the LFIB There is an advantage in using the capacity of the MPLS interworking system effectively.

Claims (11)

In the method for delivering a packet using a multi-protocol label switching network, A pre-assignment label generation step of setting an output label to a label value indicating a type of an L1 or L2 protocol to which the MPLS packet carries an input label of an MPLS packet immediately before the relay LSR; The relay LSR immediately before the exit LSR removes the label inserted in the packet received from the outside, Inserting an output label value indicating the type of L1 or L2 protocol delivered by the received packet into the packet; And transmitting the packet with the pre-assigned label inserted to an exit label switching router. delete The method of claim 1, The packet forwarding method of claim 1, wherein the network protocol of the forwardable packet is one selected from the L1 and L2 protocols. The method of claim 1, In the pre-assignment label generation step, if the packet is delivered to the ATM network, 4 is assigned as the pre-allocated label value, if the packet is delivered to the FR network, 6 is assigned to the pre-allocated label value, and the packet is transmitted to the Ethernet. A packet forwarding method comprising assigning a 7 as an assignment label value. In the method for delivering a packet using a multi-protocol label switching network, A pre-assignment label setting step of setting different labels according to the frame type of the L1 or L2 protocol constituting the deliverable packet; When a packet is forwarded from the relay label switching router to the exit label switching router, checking whether a label inserted in the forwarded packet matches one of the pre-allocated labels; Deleting the label inserted in the packet if the label inserted in the packet matches one of the pre-allocated labels; And, Obtaining information about a network to which the packet is to be delivered from a label inserted in the packet, and then forwarding the packet to a destination node corresponding to the network. The method of claim 5, The forwarding of the packet to a destination node corresponding to the network may include determining a next destination node according to a protocol characteristic of the packet. delete delete In a multi-protocol label switching system for delivering packets at high speed, An MPLS function unit for receiving an MPLS packet having a label value indicating a type of L1 or L2 protocol transmitted by an MPLS packet, checking a label value assigned to the packet, and then deleting a label included in a header; An MPLS interworking function unit for selecting an L1 or L2 protocol transmitted by an MPLS packet with reference to a label deleted from the MPLS function unit and transferring the selected L1 or L2 protocol to a corresponding L1 / L2 protocol processing unit; And, And a L1 / L2 protocol processor configured to analyze L1 or L2 protocol frame information in an MPLS packet corresponding to the selected protocol and deliver the same to the next node. delete The method of claim 9, The MPLS interworking function does not refer to a label table when the input label value of the MPLS packet received from the exit label switching router matches one of the pre-allocated label values indicating the type of L1 or L2 protocol. The label switching router, characterized in that for transmitting the frame of the MPLS packet to the L1 / L2 protocol processor.

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