KR20050064441A - Method for controlling internal connections among forward engines in mpls ler system having distributed forward engines - Google Patents

Abstract

The present invention relates to a multi-protocol label switching (MPLS) label edge router (LER) system including a plurality of forward engines, wherein a shape manager generates shape information by identifying the shapes of the forward engines, and the forward engine. Connect between them in full mesh and generate full mesh information about the internal connection between the forward engines. The resource management unit receives the shape information and the full mesh information from the shape management unit and stores the full mesh information as a full mesh table, and internally between the forward engines related to an external connection to a label switch path (LSP) or a subscriber. Detailed information about the internal connection is generated and released using the basic connection information about the connection. The connection processing unit provides basic resource connection information of the internal connection related to the external connection to the resource management unit in response to an external connection request to a label switch path or subscriber, and provides detailed information provided from the resource management unit to the forward engines. . This invention allows for fast connection and release processing regardless of the number of LSP / subscriber connections while using minimal memory resources.

Description

METHODS FOR CONTROLLING INTERNAL CONNECTIONS AMONG FORWARD ENGINES IN MPLS LER SYSTEM HAVING DISTRIBUTED FORWARD ENGINES}

The present invention relates to a distributed data communication network, and more particularly, to a method for internal connection between forward engines (FEs) in a Label Edge Router (LER) system of a multiple protocol label switching (MPLS) scheme in a distributed structure. .

In a data communication network composed of many components, a connection-based network such as a network which is usually composed of an interconnection of Asynchronous Transfer Mode (ATM), the Internet operating with Internet Protocol (IP), It is divided into a connectionless network such as an IP network. Recently developed connection-based networks allow the use of connection-based switches that work like connectionless routers. To this end, techniques known as tag or label switching or MPLS have been developed.

1 shows the structure of a typical switch network. The switch network 12 includes a plurality of connection based data switches 20a to 20d configured to act like a disconnected router.

Referring to FIG. 1 above, Label Switch Routers (LSRs) 16a to 16d are composed of typical connection based data switches 20a to 20d such as, for example, an ATM switch. Each of the data switches 20a-20d is configured to operate in conjunction with the root controllers 18a-18d. The LSRs 16a-16d are labeled Edge Routers (LERs) on disconnected networks 10, such as an IP network, to enable connectionless data transmission over the switch network 12. 14a, 14b). Data path 22 supports connectionless data transfer between LERs 14a and 14b and data switches 20a to 20d and can operate as an IP network.

The LERs 14a and 14b are each composed of a plurality of FEs connected to a subscriber or a Label Switched Path (LSP). These FEs perform the operation of establishing and releasing respective connections. When a subscriber or an LSP is connected to an FE in an MPLS LER system having a distributed FE structure, a path for establishing another FE within the LER system may be reached. The distributed FE structure refers to a structure in which packet delivery is performed in each FE by using several FEs for forwarding packets. The distributed FE structure saves system internal resources and solves the problem that packets are concentrated in a specific FE compared to a centralized structure using one FE to determine packet delivery.

2 shows an example of the path connection between distributed FEs.

As shown, the LERs 14a and 14b are each composed of a plurality of FEs 24a to 24d and 26a to 26d. In each LER 14a, 14b the specific FE 24a, 26a is responsible for connecting to the LSRs 16a, 16c, 16d of the MPLS domain 28, and the other FEs 24b-24d, 26b-26d. ) Is responsible for connecting to subscribers.

The MPLS system of the distributed FE structure as described above generates and stores connection information between FEs in the LER in a table, searches the table, and transfers corresponding information to the FE so as to be physically connected. These information are generated and stored as external connection information (LSP / subscriber connection), merging information, merging side switch connection information, forwarding side switch connection information, and forwarding information. As one entry, the remaining information is generated as many entries as the number of connected FEs. Therefore, in order to process the connection, it is necessary to find the corresponding entries in each table and process the corresponding information to establish and release the connection between internal FEs.

However, many memory resources are required to store all of the above connection information. For example, if there are n FEs, there are n-1 connections between any FE and the remaining FEs, so that connection information should be stored at each connection point for each internal connection. In addition, as the number of connections to each LSP or subscriber in each FE increases, the amount of internal connection information increases, requiring a lot of memory resources.

Accordingly, an object of the present invention, which was devised to solve the problems of the prior art operating as described above, is to provide a method for reducing memory resources required for storing connection information in an MPLS LER system having a distributed FE structure.

Another object of the present invention, in the MPLS LER system of the distributed FE structure stores only the index and basic information for the connection between the internal FE when connecting the LSP or subscriber, and the detailed information related to the actual connection between the FE with the basic connection information It is to provide a way to deliver to the FEs.

An embodiment of the present invention, which is designed to achieve the above object, controls an internal connection between the forward engines in a multi-protocol label switching (MPLS) type label edge router (LER) system including a plurality of forward engines. In the way,

Storing shape information and full mesh connection information of the forward engines in a full mesh table;

Assigning a virtual channel identifier (VCI) to a virtual path connection of each of the forward engines with reference to the full mesh table when an external connection to a label switch path (LSP) or a subscriber is required;

Obtaining detailed connection information of an internal connection between the forward engines related to the requested external connection by using the basic connection information on the requested external connection setting and the full mesh table;

And forwarding the detailed connection information to the forward engines so that the forward engines establish the required external connection.

In another embodiment of the present invention, in a multi-protocol label switching (MPLS) type label edge router (LER) system comprising a plurality of forward engines,

A shape manager configured to identify shapes of the forward engines, generate shape information, connect the forward engines in full mesh, and generate full mesh information about internal connections between the forward engines;

Receives the shape information and the full mesh information from the shape management unit, and stores the full mesh information in a full mesh table, and for the internal connection between the forward engines related to an external connection to a label switch path (LSP) or a subscriber. A resource manager for generating and releasing detailed information on the internal connection by using basic connection information;

In response to an external connection request to a label switch path or subscriber, a connection processing unit for providing basic connection information of an internal connection related to the external connection to the resource management unit and providing detailed information provided from the resource management unit to the forward engines. It is characterized by including.

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 of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

An embodiment of the present invention to be described later stores only the index and basic information for the connection between the internal FEs when connecting to the LSP or subscriber in the MPLS LER system of the distributed FE structure, the detailed information between the FE related to the actual connection is the basic information Take it and pass it to the appropriate FE. Before describing the operation according to an embodiment of the present invention in detail, the structure of the MPLS LER system to which the present invention is applied will be described.

3 illustrates the structure of the MPLS LER system according to the present invention, and as shown, a master shape manager (GSMP_master) 120, a slave shape manager (GSMP_slave) 110, and a resource manager (Label Manager) 130. And a connection processing unit 140 and a forward engine (FE) 150. Although only one FE is shown here, there are actually a plurality of FEs that are responsible for connecting to the LSP or subscriber.

In this case, GSMP means a general switch management protocol. In general, the protocol structure of a system is divided into a control plane that controls routing and a transmission plane through which actual packets are delivered. The control plane and the transmission plane can be independently developed by using a standard protocol called GSMP. . The GSMP slave, i.e., slave shape manager, is located in the control plane, and the GSMP master, i.e., master shape manager, is located in the transfer plane, and the control plane and the transfer plane are interfaced by operating the GSMP protocol between them.

Referring to FIG. 3, the slave shape management unit 110 grasps the shape of the FE of the LER system and transfers the shape to the master shape management unit 120. The master shape manager 120 connects the identified FEs to each other through a virtual path (VP) full mesh, and notifies the resource management 130 of this connection information.

The resource manager 130 receives virtual path (VP) full mesh information from the shape managers 110 and 120, stores the table as a table, and manages LSP (Label Switching Path) and subscriber connection information. In addition, the internal connection information is generated / released using basic information of the internal connection for the LSP / subscriber connection.

The connection processor 140 receives the LSP / subscriber connection request, transfers basic connection information to the resource manager 130, obtains internal connection information, and delivers the internal connection information to the FE 150. When the FE restarts or restarts the system, the internal connection information is regenerated using the internal connection information stored in the resource management unit 130 and the generated internal connection information is transferred to the FE 150 to perform a recovery function.

The FE 150 receives the internal connection information from the connection processing unit 140 and performs a setting / release command of the LSP / subscriber connection.

Basic connection information according to a preferred embodiment of the present invention refers to the connection information shown to the operator in relation to the subscriber or LSP connection, that is, the connection to the outside of the FE, such as port number, VPI, VCI, IP address, etc. for the connection. Contains information. These information are stored in the VC_MPLS table. For example, if you want to assign a subscriber to a system, the operator assigns a specific IP address to a specific port number, VPI, or VCI. The external connection information is the basic connection information. The resource manager 130 automatically performs an internal connection process so that a specific external connection is also connected to another FE in the distributed FE structure.

Then, the connection processing unit 140 passes the basic connection information on the subscriber or LSP connection to the resource management unit 130, and the resource management unit 130 for the internal connection for the corresponding subscriber or LSP connection based on the system shape information. The internal connection information is generated and transmitted to the connection processing unit 140, and the connection processing unit 140 transmits the internal connection information received from the resource management unit 130 to the FE 150.

Figure 4 shows the connection-related information of the MPLS LER system to which the present invention is applied, in particular between the FE (24a to 24d) and the switch 30 interconnecting the FE (24a to 24d), the inside of the FE position Shows connection configuration and connection related information to support it.

In the illustrated system, the switch resources are represented by VPI and VCI based on the ATM switching network. VPI is allocated by connecting the VP full mesh for the internal connection of the switch, and VCI is allocated one VCI from the VCI pool and assigned to each VPI. That is, VCI is also assigned to each connection between four FEs 24a to 24d.

Referring to FIG. 4, reference numeral 32 denotes external connection information and indicates connection information on a point where the LSP / subscriber connection meets the FE. The external connection information 32 is managed as a channel handler indicating an index value for the information on the connection point. The external connection information 32 includes an external port number, an external virtual path identifier (VPI), an external virtual channel identifier (VCI), a key value, and a channel handler value. The key value may be a subscriber IP (Internet Protocol) address in the case of a subscriber connection, and may be a destination IP address or a constraint-based (LS) identifier in the case of an LSP connection. The channel handler value is an index of the above information. In the FE, fast connection is possible by matching the external connection information 32 with the channel handler.

Reference numeral 34 is merging information necessary for merging merging side switch connections to an external connection. The channel handler values of both sides correspond to merging information. The merging information consists of a channel handler for the external connection point and a channel handler for the connection point of the FE internal switch.

Reference numeral 36 denotes information indicating merging side switch connection information indicating a connection point between the FE and the switch in the internal connection direction from the switch to the FE. The merging side switch connection information includes an internal port number of the FE, a VPI number assigned to the VP full mesh, a VCI number assigned to the VPI from the VCI pool 44, a key value, and a channel handler value. The key value may be a subscriber IP address in the case of a subscriber connection, and may be a destination IP address or a CR-LSP identifier in the case of an LSP connection. The channel handler value is an index of the information. In the FE, the merging-side switch connection information 36 is matched with the channel handler to enable fast searching.

Reference numeral 38 denotes forwarding switch connection information on the connection point between the FE and the switch in the internal connection direction from the FE to the switch. The forwarding side switch connection information 38 includes an internal port number of the FE, a VPI number assigned in the VP full mesh, a VCI number assigned from the VCI pool 44 for the VPI, a key value, and a channel handler. have. The key value may be a subscriber IP address in case of a subscriber connection, and may be a destination IP address or a CR-LSP identifier in case of an LSP connection. The channel handler is an index for the information. In the FE, the forwarding side switch connection information 38 is matched with the channel handler value to enable a fast search.

Reference numeral 40 is forwarding information, which corresponds to a key value and a channel handler value, which are information required to exit the switch from the FE. The key value may be a subscriber IP address in case of a subscriber connection, and may be a destination IP address or a CR-LSP identifier in case of an LSP connection. The channel handler value represents the connection point between the FE and the switch to go to the internal connection to the key value.

Reference numeral 42 denotes VP full mesh information. As the system runs, it maintains information about each connection to connect a VP full mesh, with one VP allocated among all FEs for internal connections between distributed FEs. The VP full mesh information 42 is allocated between the FE number (InFE) of one side, the internal port number (InPort) of one side FE, the internal FE number (OutFE) of the other side, the internal port number (OutPort) of the other side FE, and the FEs. Store the VPI number in the form of a VP mapping table.

As described above, since the FEs are connected by the VP full mesh, the VCI is allocated to the previously allocated VPI for the internal connection between the FEs when the LSP / subscriber connection occurs. To this end, the VCI pool information 44 for the system is managed to allocate / release VCIs for the corresponding internal VPIs. The VCI pool information 44 includes assignable VCI numbers.

In a preferred embodiment of the present invention, the resource management unit manages only the basic connection information by table, and when the internal connection or release request, the connection processing unit generates detailed connection information with the basic information, the VP mapping table, and the VCI pool to the FE. To convey.

5 is a view for explaining an operation example of the MPLS LER system according to a preferred embodiment of the present invention.

Referring to FIG. 5, MT and FT represent a merging table and a forwarding table, respectively. The merging table connects multiple input points of the FE to one output point for merging. The system uses a channel handler that is the index value for that connection point. Thus, information that maps multiple input connection points (channel handlers) to one output connection point (channel handlers) is included in the merging table.

In order for an FE not connected to any destination to be connected to any destination, it must first be connected to an FE connected to the destination. That is, internal connections must be made internally to the switch. The forwarding table contains information about the connection point (channel handler) at the corresponding FE to look up any destination and connect with the internal connection.

Linking an LSP connection / subscriber connection to a LER system refers to associating a destination IP address with any port, VPI, and VCI at the FE. Information about this connection point is used to determine the connection information for fast lookup at the FE. The index value (channel handler) is created by the resource management unit and transferred to the FE together with basic connection information (port number, VPI, VCI, and IP address).

When a new connection is added to the FE, packets that want to go to this connection from another FE must be connected to the added connection. Thus, when an LSP connection / subscriber connection is added, it internally establishes an internal connection with this connection from another FE. Information necessary for the internal connection is stored in tables of FT, VC_FT, VC_MT, MT, and VC_MPLS, respectively. The tables are referred to when looking up in the FE. The control plane generates information about the linked tables and delivers it to the transfer plane. This information also includes an index value (channel handler) for the connection contact in the FE to perform a quick lookup at the FE. That is, the channel handler is an index value necessary for a quick lookup in the FE and indicates information on the FE number, port number, VPI, and VCI, which are connection contact information in the FE. Therefore, the channel handler represents the FE number, the port number, the VPI, and the VCI.

The main information included in the forwarding table (FT) is the destination IP address and channel handler information in the VC_FT. The connection path through the switch connects the port number, VPI, and VCI between the two FEs using the VP mapping table and the VCI pool based on the shape information, and also creates a channel handler which is an index of the contact point. Delivered to each FE.

VC_FT includes information on the contact point where the FE and the switch are connected. The information on the connection contact includes the FE number, the port number, the VPI, the VCI, and the channel handler which is the index value for them. VC_MT includes information on the contact point between the output FE and the switch. This information includes the FE number, port number, VPI, VCI and channel handlers that are index values for them.

The merging table MT connects the input side input contact with one output contact.

VC_MPLS is information about the connection to be actually output, and contains basic connection information (FE number, port number, VPI, VCI) for LSP connection / subscriber connection. Create a handler and pass it to the FE together. This information is stored in a table called VC_MPLS.

The resource manager reads the FE number and VPI number from the VP mapping table with the port number and creates a channel handler using the VCI number read from the VCI pool. The channel handler value is stored in the VP_MPLS table for basic connection information. The channel handler is used to find MT entries, VC_MT entries, VC_FT entries and FT_entries. The connection processor then uses the VC_MPLS entry, the MT entries, the VC_MT entries, the VC_FT entries, and the FT entries for the connection between the internal FEs 24a to 24d.

6 is a signal flow diagram illustrating the operation of the MPLS LER system according to a preferred embodiment of the present invention.

Referring to FIG. 6, when the system is initially driven, the shape manager determines shape information of FEs and allocates VPIs between the FEs to determine VP full mesh information. In step 210, the shape information and the VP full mesh information are stored in the shape information table and the VP full mesh table by the resource manager, respectively. The VP full mesh table will also be referred to as a VP mapping table.

In step 220, when a connection request to the LSP or subscriber is generated to the connection processor, the connection processor requests connection establishment to the resource manager. The resource manager then allocates the VCI obtained from the VCI pool for each VP connection between the FEs for the LSP / subscriber connection with reference to the VP full mesh table. The basic connection information VP_MPLS for the connection between the internal FEs related to the LSP / subscriber connection is stored in the VP_MPLS table, and the result is transmitted to the connection processing unit.

In step 230, the connection processing unit calls the resource management unit to request retrieval of detailed connection setting information between internal FEs using basic connection information and VP full mesh table information stored prior to LSP / subscriber connection. The resource manager generates detailed connection information, VC_MPLS, MT, VC_MT, VC_FT, FT, etc. between internal FEs using VP full mesh information, and transfers the generated detailed connection information to the connection processor.

In step 240, the connection processor transfers the delivered detailed connection information to FEs related to the connection and receives a response thereto. The FEs then establish a physical connection with reference to the detailed decision sheet.

In step 250, when a request for disconnection to the LSP / subscriber occurs, the connection processor requests the connection information of the LSP / subscriber to release by calling the resource manager. The resource manager generates detailed information VC_MPLS, MT, VC_MT, VC_FT, FT, etc. between internal FEs based on the basic information between internal FEs and VP full mesh information obtained from the VP full mesh table, and provides them to the connection processor. The connection processor searches the basic connection information table with the received information and finds the corresponding entries.

In step 260, the connection processor transfers the found entries to each FE as connection release information. The FE releases a physical connection based on the disconnection information and returns a response. In step 270, the connection processor receives a response to the connection release from the FEs and requests the connection to the resource manager. Then, the resource manager recovers the VCI assigned to the internal VPI for the connection from the VCI pool, retrieves the basic connection information VC_MPLS between the internal FEs, and deletes the corresponding entry from the table.

Meanwhile, in the detailed description of the present invention, specific embodiments 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 not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

In the present invention operating as described in detail above, the effects obtained by the representative ones of the disclosed inventions will be briefly described as follows.

The present invention enables fast connection and release processing regardless of the number of LSP / subscriber connections while using minimal memory resources in performing connection and release between forward engines in a distributed structure in the MPLS LER system.

1 illustrates the structure of a typical switch network.

2 is an example of a path connection between forward engines.

3 is a view showing the structure of the MPLS LER system according to the present invention.

4 is a diagram illustrating connection related information of an MPLS LER system to which the present invention is applied.

5 is a view for explaining an operation example of the MPLS LER system according to a preferred embodiment of the present invention;

6 is a signal flow diagram illustrating operation of the MPLS LER system in accordance with a preferred embodiment of the present invention.

Claims (9)

A method of controlling internal connections between forward engines in a multi-protocol label switching (MPLS) type label edge router (LER) system including a plurality of forward engines, the method comprising: Storing shape information and full mesh connection information of the forward engines in a full mesh table; Assigning a virtual channel identifier (VCI) to a virtual path connection of each of the forward engines with reference to the full mesh table when an external connection to a label switch path (LSP) or a subscriber is required; Obtaining detailed connection information of an internal connection between the forward engines related to the requested external connection by using the basic connection information on the requested external connection setting and the full mesh table; And forwarding the detailed connection information to the forward engines to cause the forward engines to establish the required external connection. The method of claim 1, wherein the full mesh table, And a virtual path identifier (VPI) number assigned between forward engines associated with the number and internal port number of one forward engine and the number and forward port number of the other forward engine for each of the internal connections between the forward engines. Said method. The method of claim 1, wherein the basic connection information, The method comprising a port number, a virtual path identifier (VPI), a virtual channel identifier (VCI) and an internet protocol (IP) address. The method of claim 1, Obtaining a basic connection information corresponding to the external connection information to be released by referring to the full mesh table when an external connection to the label switch path or subscriber is requested; Obtaining detailed connection information of an internal connection between the forward engines related to the external connection to be released by referring to the basic connection information and the full mesh table; And forwarding the detailed connection information to the forward engines to cause the forward engines to release the required external connection. In a multi-protocol label switching (MPLS) type label edge router (LER) system comprising a plurality of forward engines, A shape manager configured to identify shapes of the forward engines, generate shape information, connect the forward engines in full mesh, and generate full mesh information about internal connections between the forward engines; Receives the shape information and the full mesh information from the shape management unit, and stores the full mesh information in a full mesh table, and for the internal connection between the forward engines related to an external connection to a label switch path (LSP) or a subscriber. A resource manager for generating and releasing detailed information on the internal connection by using basic connection information; In response to an external connection request to a label switch path or subscriber, a connection processing unit for providing basic connection information of an internal connection related to the external connection to the resource management unit and providing detailed information provided from the resource management unit to the forward engines. Said system comprising: a. The method of claim 5, wherein the full mesh table, And a virtual path identifier (VPI) number assigned between forward engines associated with the number and internal port number of one forward engine and the number and forward port number of the other forward engine for each of the internal connections between the forward engines. Said system. The method of claim 5, wherein the basic connection information, Said system comprising a port number, a virtual path identifier (VPI), a virtual channel identifier (VCI) and an internet protocol (IP) address. The method of claim 5, wherein the resource management unit, When the external connection to the level switch path or the subscriber is requested through the connection processing unit, basic connection information corresponding to the external connection information to be released is obtained by referring to the full mesh table, and the basic connection information and the full mesh are obtained. The system, characterized in that for obtaining detailed connection information of the internal connection between the forward engines related to the external connection to be released by referring to the table to the connection processor. The method of claim 5, wherein the connection processing unit, Upon restarting the forward engines or upon restarting the system, the internal connection information is regenerated using the basic connection information stored in the resource manager to recover internal connections in the forward engines. The system, characterized in that provided.