KR20010065413A - Mpls system and initialize method thereof - Google Patents

Abstract

PURPOSE: An MPLS(Multi Protocol Label Switching) system and a method for initializing thereof are provided to control the whole traffic flow of an MPLS network and to prevent traffic overload environments in an MPLS system. CONSTITUTION: An NMS(Network Management System)(50) controlling the whole traffic of an MPLS network receives initial information for each node(30,32,34) and stores it in its internal storage unit. If one of the nodes(30,32,34) gets downed, the initial information of the downed node is provided to an operator through the NMS(50). If the operator modifies initial information for the downed node, the NMS(50) stores the modified initial information of the downed node in its internal storage. The nodes(30,32,34) request the NMS(50) to provide their respective initial information before executing LDP(Label Distribution Protocol) operations to set up LSPs(Label Switched Paths). Based on an SNMP(Simple Network Management Protocol), each of the nodes downloads its own initial information from the NMS(50) using a file system its own OS(Operating System) provides.

Description

Multi-protocol label switching system and its initialization method {MPLS SYSTEM AND INITIALIZE METHOD THEREOF}

The present invention relates to a network system, and more particularly, to an initialization method in a multi-protocol label switching (MPLS) system.

The explosive growth of Internet users and traffic volumes, and the commercialization of new applications and the Internet, are driving the need for Quality of Service (QoS) and service availability. Multi Protocol Label Switching (MPLS) is an ongoing standard in the Internet Engineering Task Force (IETF) to meet this need. MPLS is independent of two-layer networks, but ATM cell switching effectively supports MPLS's concept of label swapping. MPLS is now recognized as the most powerful IP-over-Asynchronous Transfer Mode (IP-over-ATM) technique in backbone networks.

The early Internet was mainly used for file transfer protocol (FTP), e-mail, and remote-login between some research institutes and universities. However, the use of the Internet has exploded due to the spread of personal computers and the emergence of the Word Wide Web. As a result, processing capacity for rapidly increasing traffic capacity is required. In addition, with the emergence of new applications such as video conferencing, there is an increasing demand for QoS functions. User groups require different service availability and QoS, and therefore services and charges.

The current Internet structure does not meet these needs. In other words, software performs three-tier routing, supports only best-effort services without guarantees, and the possibilities for traffic engineering or aggregation are extremely limited. MPLS solves this problem as follows:

Combine label swapping concepts with 3 routing.

Improves the price-per-performance of 3 routing

Provides scalability through traffic aggregation

Traffic engineering can be provided by supporting new routing services.

Guarantee QoS

MPLS uses a scheme that simplifies forwarding by introducing the concept of connection-oriented on a connectionless IP network. That is, a fixed path, that is, a label switched path (LSP) from an edge node to another edge node in a high-speed switching network equipped with the MPLS function, for example, an ATM network, is set at a call setup time. Thus, the actual IP packet is delivered in the MPLS network through a preset LSP. At this time, a protocol for establishing an LSP between nodes in an MPLS network is required. IEFT proposed LDP (Label Distribution Protocol).

In FIG. 1, there are a plurality of nodes, for example, a plurality of edge router ERs and label switch routers LSRs, in the MPLS network 10. 2 shows the configuration of the LSP 12 between nodes in the MPLS network 10.

Once a particular LSP has been set up in the MPLS network 10, each edge router ER is configured to;

(1) Parse the header and set which LSP to use

(2) The packet is attached with an LSP ID in the form of a label.

When this process is completed, each node sees only the label information attached to the packet and transmits it at high speed along the LSP.

A more detailed description of the LSP configuration is as follows.

Each node performs LDP operation to establish LSPs with neighbor nodes. A particular node negotiates a label to use with its upstream and downstream neighbors for each forwarding equivalence class (FEC) it has. That is, it is determined which label to use for the LSP between the upstream node ↔ specific node (downstream node) or the specific node (upstream node) ↔ downstream node. The basic way to set up an LSP is as follows: First, the upstream proposes to the downstream to negotiate a label with each other for the LSP for a particular FCE. 3A shows the path of a label request for the LSP. The path of the label request consists of R1 → R2 → R3 → R4 → R5. The downstream node then assigns a label for that FEC and informs the upstream peer. 3b shows a path for notifying upstream peers of the label for the LSP. The path for notifying the upstream peer is composed of R5 → R4 → R3 → R2 → R1. As a result, each node creates a table called LIB (Label Information Base) that functions as a mapping between the label representing the LSP of the link and the FEC. Whenever the neighbor information of a specific node changes, the node renegotiates with the newly recognized neighbor node to generate an LSP.

When each node of the MPLS network 10 is booted from the system, as shown in FIG. 4, each node 30, 32, and 34 first sets the initial information of the node in its own storage medium, NVRAM (LMS), for LSP configuration. Read from non volatile Random Access Memory (40, 42, 44) (Step ①). The NVRAM is a memory provided in the nodes 30, 32, and 34, respectively, for the purpose of storing the initial information of the nodes themselves. And the details of the initial information of the own node will be described later with the embodiment of the present invention. After that, the actual LDP operation for setting the LSP proceeds (step ②). When the initial information such as the interface internet protocol address of the LDP is changed during the LDP operation, each of the nodes 30, 32, and 34 has its own NVRAM (40, 42) based on the storage command of the operator. At step 44, the changed initial information is stored.

As described above, in order to configure the LSP, each of the existing MPLS network nodes uses a technique that reads information necessary for itself from NVRAM and stores data in the NVRAM. Therefore, it does not take into account the overall traffic situation of the MPLS network, so it takes a lot of time to deal with the proliferation of data at a particular node. For example, when a specific node in an MPLS network is down and rebooted due to traffic overload, the NVRAM reads initial information previously stored in its NVRAM. The previous initial information stored in NVRAM cannot eliminate traffic overload, so that particular node remains in the traffic overload environment.

Accordingly, an object of the present invention is to provide an apparatus and an initialization method for controlling traffic flow of an entire MPLS network in an MPLS system.

Another object of the present invention is to provide an apparatus and an initialization method for preventing a traffic overload environment in an MPLS system.

In accordance with the above object, the present invention provides a multiprotocol label switching system comprising: a plurality of nodes performing a multiprotocol label switching function in a multiprotocol label switching network; Controls the overall traffic on the multi-protocol label switching network, receives initial information about each of the plurality of nodes from the plurality of nodes, and stores the initial information of the down node among the stored initial information when a predetermined node is down. A network management device provided to an operator and providing the stored initial information to the requesting node according to the initial information request among the plurality of nodes; Each of the plurality of nodes requests its initial information to the network management device and performs its own initial information provided by the network management device before performing a label distribution protocol operation for forming a label switching path between the nodes. Using the label distribution protocol.

The present invention also provides a protocol label including a multi-protocol label switching network, a plurality of nodes in the switching network that function as the multi-protocol label switching, and a network management device for controlling overall traffic on the multi-protocol label switching network. A method of initializing each of the plurality of nodes in a switching system, the method comprising initializing its initial information for each of the plurality of nodes before performing a label distribution protocol operation for forming a label switching path between the nodes at system boot time. And a process of requesting a network management device having initial information and performing the label distribution protocol operation using its initial information provided by the network management device.

The present invention also provides a protocol label including a multi-protocol label switching network, a plurality of nodes in the switching network that function as the multi-protocol label switching, and a network management device for controlling overall traffic on the multi-protocol label switching network. In the initializing method in the network management device in a switching system, the initial information for each of the plurality of nodes received from the plurality of nodes and stored, and the stored initial to the operator when any node of the plurality of nodes down; Providing initial information of the down node among the information, storing the initial information changed according to the initial information change of the operator for the down node in correspondence with the down node, and storing the plurality of nodes. Request of initial information Wherein the initial information corresponds to the requested node is characterized by constituted by any process available in the node.

1 is an example configuration of an MPLS network;

FIG. 2 is a diagram illustrating LSP configuration in an MPLS network; FIG.

3A is a diagram for explaining a label request for an LSP;

3B is a diagram for explaining notifying a label for an LSP;

4 is a view for explaining the operation of each part for LSP setting according to the prior art;

5 is a view for explaining the operation of each part for LSP setting according to an embodiment of the present invention;

6 is a control flowchart of each node according to an embodiment of the present invention;

7 is a control flowchart of MNS according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the same elements in the figures are denoted by the same reference numerals or the same reference numerals wherever possible. In addition, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

5 is a view for explaining the operation of each unit for LSP configuration according to an embodiment of the present invention. It should be understood that the nodes 30, 32, and 34 of FIG. 5 are represented as an example of a plurality of nodes provided in the MPLS network 10 shown in FIGS.

Referring to FIG. 5, in the embodiment of the present invention, each of the plurality of nodes 30, 32, and 34 provided in the MPLS network 10 and performing the MPLS function includes an NVRAM (eg, a plurality of nodes in the prior art). 40, 42, 44 in FIG. In the embodiment of the present invention, instead of using the NMS (Network Management System) 50 to perform the MPLS network management so that the LDP operation for LSP configuration for each of the plurality of nodes (30, 32, 34) do.

The operation of the MNS 50 in the embodiment of the present invention is as follows. The MNS 50 controls the overall traffic on the MPLS network and receives initial information about each of the plurality of nodes 30, 32, 34 from the plurality of nodes 30, 32, 34 and stores them in the internal storage device. 5 (i) of FIG. 5, the initial information of the down node among the initial information stored when the predetermined node is down is provided to the operator through the NMS 50. If the operator changes the initial information on the node down through the NMS 50, the operator stores the changed initial information in correspondence with the node down on the internal storage. In addition, the stored initial information is provided to the requested node according to the initial information request among the plurality of nodes 30, 32, and 34 (ⓐ in FIG. 5).

In addition, operations of each of the plurality of nodes 30, 32, and 34 according to an embodiment of the present invention are as follows. Each of the plurality of nodes 30, 32, and 34 requests its initial information to the NMS 50 before performing the LDP operation (B in FIG. 5) to form an LSP between the nodes. The LDP operation is performed using its initial information provided by 50).

In order to transmit initial information from the NMS 50 to the plurality of nodes 30, 32, 34, an embodiment of the present invention uses Simple Network Management Protocol (SNMP), and each node 30, 32, 34 is used. Downloads its initial information received from the NMS 50 based on SNMP using a file system provided by its operating system (OS).

The following information is an example of information to be negotiated between nodes for LSP configuration. That is, it is an example of initial information that each node 30, 32, 34 in the MPLS network 10 should have. The initial information is provided to the requested node of the plurality of nodes 30, 32, and 34 from the NMS 50 at the request of the corresponding node according to an embodiment of the present invention.

-Label Switch Router Identifier (LSR ID): A unique number representing each node in the MPLS network, which is expressed in the form of an IP address.

LDP Version: indicates the version of LDP that operates on a particular node. An LDP operation is performed to establish an LSP between nodes in the MPLS network 10. The first comparison is the LDP version. The LDP versions are different from each other and do not set the LSP.

TCP (Transmission Control Protocol) Connection Timeout: For LDP operation between two nodes in MPLS network, it must communicate with each other through TCP / IP (Transmission Control Protocol / Internet Protocol). In other words, data sent and received during LDP operation is transferred through TCP / IP. At this time, it basically means time to maintain TCP connection. That is, if TCP data is not transmitted from the partner node within this time, it is determined that the partner node is disconnected.

UDP (User Datagram Protocol) connection timeout: Before performing LDP operation between nodes in the MPLS network 10 or during operation, it is necessary to periodically recognize who the neighboring nodes are. Nodes recognize each other's neighbors through UDP / IP (User Datagram Protocol / Internet Protocol) data transfer. It means the UDP connection maintenance time at this time. That is, it receives data from a specific neighbor node and is recognized as a neighbor node. If data does not come back within a given time (UDP connection timeout), it is no longer recognized as a neighbor node.

Session retry: The TCP connection can be disconnected for a variety of reasons, in which case a new LDP operation must be initiated. At this time, the number of times is determined, and the session retry is the number of times.

Control Mode: The method of establishing an LSP between nodes in the MPLS network 10 is as described above. Basically, the upstream node asks the downstream node for the label to use for the LSP, and in response, the downstream allocates the spare label to the upstream. At this point, the downstream side should use the method of requesting his downstream label ("ORDERED") when it is connected to his downstream, or if he decides without prompting the downstream, Indicates whether to use the allocation method ("INDEPENDENT method").

Retention mode: Determines how to maintain a label assigned from a neighbor node. Conservative mode keeps only the labels received from the downstream link when forwarding data. This is especially useful when the number of label spaces is limited, such as ATM switches. In liberal mode, label assignments are maintained from all neighboring nodes regardless of validity. The advantage of this approach is that the label already exists, so it is responsive to routing changes.

Advertisement mode: In setting up the LSP, specify how the downstream notifies the upstream label. Downstream on demand is a way for the upstream to notify the upstream in response when it requests a label for the LSP. The downstream unsolicit method is to inform all of its upstream nodes unconditionally when there is a free label regardless of the upstream label request.

-Link type: LDP parameter specifies what type of lower link to use during negotiation. Current examples are classified into ATM, FR (Frame Relay), and other types.

Maximum Protocol Data Unit (PDU) Length: Specifies the maximum length of an LDP packet in the exchange of LDP data.

6 is a control flowchart of each of the nodes 30, 32, and 34 according to an embodiment of the present invention, and FIG. 7 is a control flowchart of the MNS 50 according to an embodiment of the present invention.

Hereinafter, an operation according to an embodiment of the present invention will be described in more detail with reference to FIGS. 1 to 3A, 5B, 5, 6, and 7.

The node operator of the plurality of nodes 30, 32, and 34 boots the system of the node when the system of the node operates normally (step 100 of FIG. 6). Thereafter, the node requests its initial information to the NMS 50 before performing the LDP operation for forming the LSP between the nodes (step 102 of FIG. 6).

Meanwhile, the NMS 50 receives initial information about each of the plurality of nodes 30, 32, and 34 in operation from each node and stores the initial information in each internal storage device (200 in FIG. 7). Each of the plurality of nodes 30, 32, 34 in operation transmits the changed initial information to the NMS 50 when an initial information change occurs inside. In addition, each of the plurality of nodes 30, 32, 34 periodically transmits its initial information to the NMS 50.

When the down node occurs among the plurality of nodes 30, 32, and 34 in the NMS network 10 (step 202 of FIG. 7), the NMS 50 transmits initial information of the down node to the operator of the NMS 50. To provide. That is, the MNS 50 displays the initial information already stored in the internal storage device corresponding to the down node on the monitor of the MNS 50 and informs the NMS operator (step 204 of FIG. 7). Accordingly, the NMS operator may change the initial information of the down node in consideration of the overall traffic situation of the MPLS network 10. When the NMS operator changes the initial information of the down node (step 206 of FIG. 7), the NMS 50 stores the changed initial information in an internal storage device (step 208 of FIG. 7).

In addition, when the NMS 50 receives its initial information request from a predetermined node among the plurality of nodes 30, 32, and 34 (step 210 of FIG. 7), the NMS 50 reads the initial information of the requested node from the internal storage device. The initial information is transmitted to the requesting node (step 212 of FIG. 7).

When the node requesting initial information among the plurality of nodes 30, 32, and 34 receives its initial information from the NMS 50 (step 104 of FIG. 6), the LDP operation is performed using the received initial information. (Step 106 of FIG. 6), and then LSP setting (step 108 of FIG. 6).

In the above description of the present invention, a specific embodiment has been described using several nodes in the NMS network, but various modifications can be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be defined by the described embodiments, but should be determined by the equivalent of claims and claims.

As described above, the present invention can stabilize the MPLS network by managing initial information of each node in consideration of the overall traffic of the network. In addition, since the MVRAM dedicated to storing initial information is not considered for each node in the MPLS network, the corresponding cost can be reduced.

Claims (5)

In a multiprotocol label switching system: A plurality of nodes performing a multiprotocol label switching function in the multiprotocol label switching network; Controls the overall traffic on the multi-protocol label switching network, receives initial information about each of the plurality of nodes from the plurality of nodes, and stores the initial information of the down node among the stored initial information when a predetermined node is down. A network management device provided to an operator and providing the stored initial information to the requesting node according to the initial information request among the plurality of nodes; Each of the plurality of nodes requests its initial information to the network management device and performs its own initial information provided by the network management device before performing a label distribution protocol operation for forming a label switching path between the nodes. Multi-protocol label switching system for performing the label distribution protocol operation. The protocol label switching system of claim 1, wherein the network management apparatus stores initial information changed according to the initial information change of the operator. The protocol label switching system of claim 1 or 2, wherein communication between the network management device and the plurality of nodes is performed by a simple network management protocol (SNMP). The plurality of nodes in the protocol label switching system having a multi-protocol label switching network, a plurality of nodes serving as the multi-protocol label switching function in the switching network, and a network management device for controlling the overall traffic on the multi-protocol label switching network. In the initialization method in each of the three nodes, Requesting a network management device having initial information of each of a plurality of nodes before performing a label distribution protocol operation for forming a label switching path between nodes during system booting; And performing the label distribution protocol operation using its initial information provided by the network management apparatus. The network in the protocol label switching system having a multi-protocol label switching network, a plurality of nodes in the switching network to perform the multi-protocol label switching function, and a network management device for controlling the overall traffic on the multi-protocol label switching network. In the initialization method in the management device, Receiving and storing initial information about each of the plurality of nodes from the plurality of nodes and providing initial information of the down node among the stored initial information to an operator when any node of the plurality of nodes is down; , Storing initial information changed according to the operator's initial information change for the downed node in correspondence with the downed node; And providing initial information corresponding to the requested node among the last stored initial information to the requesting node when the initial information is requested among the plurality of nodes.