KR100310308B1 - Method for Providing Differentiated Service According to FC in AMT-based MPS - Google Patents

Abstract

The present invention is to assign a label reflecting the quality of service requirements in an Asynchronous Transfer Mode (ATM) -based Multi Protocol Label Switch (MPLS) to provide differentiated services according to the same forward class. The purpose of the ATM-based MPLS to provide a differentiated service providing method according to the FEC.

According to the present invention, there is provided a differentiated service providing method applied to ATM-based MPLS, comprising: a first step of receiving an Internet packet and analyzing a destination address and a service level; And a second step of determining a forward equal class according to the analyzed destination address and service class and mapping a label.

Description

How to provide differentiated services according to FC in ATM based MPS

The present invention is to assign a label reflecting the quality of service requirements in an Asynchronous Transfer Mode (ATM) -based Multi Protocol Label Switch (MPLS) to provide differentiated services according to the same forward class. The present invention relates to a method for providing differentiated services according to FEC in ATM-based MPLS.

Recently, a study on MPLS is being conducted as a method for providing an efficient Internet service. MPLS performs IP forwarding using a label promised between neighboring routers or switches that recognize MPLS without using the longest prefix match method, which is an existing IP forwarding method.

In addition, scalability of the core network may be satisfied through a data merging function of giving the same label to data flows having the same forwarding class.

The Working Group (WG) of the Internet Engineering Task Force (IETF) organizes data flows with the same destination by forming the same forwarding class (FCE). It is recommended to follow 'Router Id.' To bind all data flows connected to the same router as IP prefix type 'and to assign a label to each data flow.

In addition, the conventional Internet service has supported only the best-effort service without differentiating service quality. Of course, there was a type of service (ToS) octet specifying the type of service in the existing IP header, but the existing routers did not use it.

However, researches on differentiated services on the Internet are in progress according to the demand for multimedia services due to the emergence of the World Wide Web (WWW) and the activation of electronic commerce.

These activities provide services differentiated into three classes, best-effort service, guaranteed service and control load service, by the Reverse Resource Reservation Protocol (RSVP) around IETF, which represent more general and explicit service class than RSVP. Differentiated service that defines DS byte to represent code point according to traffic characteristics of each data flow as DS byte and packet forwarding differs according to DS byte. Research is ongoing.

However, in the case of RSVP, differentiated services are available through resource flow method for each data flow, but routers or switches in the core network must manage traffic information for each data flow. There is a problem of salability, and there is a problem that there must be overhead for supporting RSVP protocol.

In the case of differentiated service, traffic conditioning is performed at the edge router, and the core router performs simple IP forwarding according to per-hop-behavior (PHB) of the data flow. A study on how to provide a service by performing forwarding () is being conducted.

MPLS has emerged as a technology that solves the scalability problem of existing routers and enables fast forwarding.

MPLS merges data flows with the same forward class (FEC) and maps a label to the merged data streams to improve the scalability of the core network. Can be reduced.

In addition, by separating routing and forwarding, a change in the conventional routing function is not required, and fast forwarding is possible by using a short label match method without using the conventional longest prefix match method.

In IETF's MPLS WG, stream merging is performed by mapping a single label to data flows with the same destination as a method of determining the same forward class. We propose a method for mapping a label for each label.

As a result, the level of demand for all services has been provided as best-effort without considering different service characteristics for each data flow.

Therefore, there has been a demand for the development of a label assignment method that reflects the service demand quality.

The present invention has been made to meet the requirements as described above, and when the ATM switching system performs the ATM-LER role, the destination IP address prefix and CoS in the IP packet header received from the IP data flow. Provides a service that satisfies the quality of service requirements by configuring the FEC using the field and setting the granularity of the label using 'COS TLV' and 'FEC TLV' of the label mapping message sent and received in the LDP process required for LSP setup. The purpose is to provide differentiated service provision method according to FEC in ATM-based MPLS.

1 is a configuration diagram of an ATM switching system for interworking with an MPLS network in a ships-in-the-night mode to which the present invention is applied;

2 is a header diagram of an Internet protocol packet used in the present invention.

3A is a packet diagram of a label mapping message used in the present invention.

3b is a packet diagram of a label request message used in the present invention;

4 is a configuration diagram of a forward information table used in the present invention;

5 is an explanatory diagram of forward equality determination and label mapping for service differentiation used in the present invention;

6 is a flowchart illustrating a label assignment process according to FEC considering a service class in an ATM-LER according to an embodiment of the present invention;

7 is a flowchart illustrating a label assignment process according to FEC considering a service class in an ATM-LSR according to an embodiment of the present invention.

♠ Explanation of symbols on the main parts of the drawing ♠

101: asynchronous transmission mode access module 102: internet protocol access module

103: interconnect switch 104: operation and maintenance module

According to the present invention for achieving the above object, there is provided a differentiated service providing method applied to ATM-based MPLS, comprising: a first step of receiving an Internet packet, analyzing a destination address and a service level; A second step of judging whether there is a forward equality level in accordance with the new Internet data flow in the existing stream that has been determined; A third step of mapping to a label that already exists as a result of the determination of the second step; A fourth step of establishing a LDP session with the counterpart LSR in order to map a label by determining a new forward equal rank if it does not exist as a result of the determination of the second step; A fifth step of transmitting a label request message to a counterpart LSR through an established LDP session; And a sixth step of receiving a label mapping message from the counterpart LSR, binding the mapped label, and storing the mapped label.

According to the present invention, there is provided a differentiated service providing method applied to ATM-based MPLS, comprising: establishing an LDP session with a counterpart LSR and analyzing a FEC-TLV of a received label mapping message; A second step of analyzing the COS-TLV in the label mapping message if the FEC type is defined to give an FEC for the data flow as a result of the first step analysis; A third step of searching the forward information table to determine whether an FEC corresponding to the new data flow has already been granted; A fourth step of mapping the label given to the existing FEC by determining the same level as the existing FEC if it is given as a result of the determination of the third step, and determining a new FEC and mapping a new label if it is not given; And a fifth step of determining a new FEC and mapping a new label when the FEC type is designated as an IP prefix as a result of the analysis of the first step.

According to the present invention, there is provided a differentiated service providing method applied to an ATM-based MPLS for a computer, comprising: a first step of receiving an Internet packet and analyzing a destination address and a service level; And a recording medium on which a program capable of executing a second step of mapping a label by determining a forward equal class according to the analyzed destination address and a service class is provided.

According to the present invention, there is provided a differentiated service providing method applied to an ATM-based MPLS to a computer, comprising: establishing a LDP session with a counterpart LSR and analyzing an FEC-TLV of a received label mapping message; A second step of analyzing the COS-TLV in the label mapping message if the FEC type is defined to give an FEC for the data flow as a result of the first step analysis; A third step of searching the forward information table to determine whether an FEC corresponding to the new data flow has already been granted; A fourth step of mapping the label given to the existing FEC by determining the same level as the existing FEC if it is given as a result of the determination of the third step, and determining a new FEC and mapping a new label if it is not given; And a recording medium recording a program capable of executing the fifth step of determining a new FEC and mapping a new label when the FEC type is designated as an IP prefix as a result of the analysis of the first step.

In the following, with reference to the accompanying drawings, a preferred embodiment of a method for providing differentiated services according to FEC in ATM-based MPLS according to the present invention will be described in detail.

The MPLS interface type of the ATM switching system may be configured as an ATM-LER configured to receive a packet of IP data flows and establish an adjacent LSR and an LSP, and an ATM-LSR that configures an adjacent LER or an LSR and an LSP.

In addition, the ATM-LER is connected to routers performing IP forwarding through a physical link provided by an ATM switching system (physical link (DS1, E1, DS3, STM1)). After setting the LSP for the IP packet stream, the IP packet is encapsulated in the IP packet and the IP stream is transmitted to the LSR in which the LSP is set.

In addition, the ATM-LSR transmits an IP stream by swiping to an output label corresponding to an input label.

In addition, the label allocation process reflecting the quality of service requirements in ATM-LER and ATM-LSR is composed of FEC using IP address prefix of destination and CoS of IP data flow, which is more scalability than the method of configuring FEC for each data flow. It is possible to solve the problem of failing to provide differentiated services when granting FEC only by IP address prefix.

Therefore, it is possible to provide various services to network operators by providing a basis for providing differentiated services required by subscribers while satisfying scalability through the same forward rating, which is the basic concept of MPLS.

In addition, subscribers can deliver high-speed information according to MPLS's short label match method as well as the best-effort service that has been provided through the Internet, and can suggest a service demand level reflecting subscriber's needs.

1 is a block diagram of an ATM switching system for interworking with an MPLS network in a ships-in-the-night mode to which the present invention is applied.

As shown in the figure, the ATM switching system for interworking with the MPLS network in the ships-in-the-night mode to which the present invention is applied, the MPLS while maintaining the signaling (signaling) necessary to provide services to ATM subscribers The ATM interface and the MPLS interface exist in a single exchange system.

The configuration of such a switching system includes a routing protocol and an LDP for providing an MPLS service by accessing an ATM access module 101 which performs signaling protocol processing and connection control functions for an ATM subscriber, a router of an IP network, or a LER having an MPLS function. Internet protocol access module 102 for processing protocols, interconnected ATM module 103 interconnecting distributed ATM access module 101 and distributed Internet protocol access modules 102, and operator interface and operation and maintenance within the system. It consists of an Operation & Maintenance Module (OMCM) 104 that performs a function.

2 is a header diagram of an Internet protocol packet used in the present invention.

As shown in the figure, the header structure of the Internet protocol packet used in the present invention is of two types: IPv4 (a) and IPv6 (b).

In the figure, the ToS area 201 defines a service type, and the CoS value is included in the content of the ToS area 201.

And, the destination internet protocol address 202 means a destination to which a packet is to be delivered.

In order to determine the FEC by analyzing the input IP packet, the ToS area 201 and the destination IP address 202 are referred to.

Ingress ATM-LER receives the IP packet to determine the FEC, and stores the destination IP address 202 and information about the CoS in the forwarding information table, and then through the LDP session control to the exit point ( It is responsible for setting up the LSP up to the egress point.

The LDP message necessary for LSP configuration is generated by referring to the IP header. In addition, in the case of an egress ATM-LER, the forwarding information table is packet forwarded after removing the incoming label.

3A is a packet diagram of a label mapping message used in the present invention, and FIG. 3B is a packet diagram of a label request message used in the present invention.

The Label Distribution Protocol (LDP) message is used for LSP configuration and, in the case of an ingress ATM-LER, generates a label mapping message of FIG. 3A and a label request message of FIG. 3B with reference to a forwarding information base (FIB).

The generated message includes a Type-Length-Value (FEC-TLV) 302, an ATM-Label-TLV 303, a COS-TLV 304, a Hop Count TLV 305, and a Path Vector TLV 306. do.

4 is a configuration diagram of a forward information table used in the present invention.

As shown in the figure, a forwarding information base (FIB) table used in the present invention stores an IP address 401, next hop information 406, and an output interface 407 by a routing protocol such as OSPF. do.

In addition, it stores the input interface 404, the input label 405, the FEC 403, and the CoS 402 determined when the IP packet is received, and label mapping for the FEC when the LSP is set up to an egress point. ) And the determined output label 408 is stored.

5 is an explanatory diagram for forward equality determination and label mapping for service differentiation used in the present invention.

In the figure, data flow 1 (Flow 1), data flow 2 (Flow 2), and data flow 3 (Flow 3) have the same destination IP prefix and map to one label when the CoS region values representing the service class are the same. The stream is merged into FEC1 which is mapped.

In addition, since data flow 4 (Flow 4) and data flow 5 (Flow 5) require CoS area values having the same destination IP prefix but different service classes, the streams are streamed to FEC2 that is mapped to a new label rather than merged into FEC1. This is merged.

The packet is encapsulated in an IP packet stream that is merged and transmitted by each FEC1 and FEC2 and then transmitted.

The label of the IP packet stream is mapped to the VPI / VCI of the ATM cell on the ATM switch.

6 is a flowchart illustrating a label assignment process according to FEC considering a service class in an ATM-LER according to an embodiment of the present invention.

As shown in the figure, the label allocation process according to the FEC considering the service class in the ATM-LER according to an embodiment of the present invention, by receiving the IP packet for the new data flow (601), the destination in the received IP packet It is analyzed whether the IP address is an IP address existing in the forward information table (602).

Thereafter, the CoS region in the IP header is analyzed (603) to determine whether the FEC corresponding to the new IP data flow is already determined in the existing stream (604).

As a result of the determination, the existing label is used, and if not, a new FEC is determined and the label is mapped.

That is, after establishing an LDP session with the counterpart LSR in order to map a label for the FEC of the new data flow (605), the label request message is transmitted to the counterpart LSR through the established LDP session (606). .

Subsequently, a label mapping message is received from the counterpart LSR (607), the mapped label is bound and stored (608).

7 is a flowchart illustrating a label assignment process according to FEC considering a service class in an ATM-LSR according to an embodiment of the present invention.

As shown in the figure, the label assignment process according to the FEC considering the service class in the ATM-LSR according to an embodiment of the present invention, first after establishing the LDP session with the counterpart LSR (701), the label from the counterpart LSR The mapping message is received (702), and a message error is checked (703).

Thereafter, it is determined whether there is an error (704), terminates if there is an error, and if there is no error, analyzes the FEC-TLV in the label mapping message received from the counterpart LSR (705), so that the FEC type is the FEC for the data flow. If it is defined to give a COS-TLV in the label mapping message is analyzed (707).

Next, the forward information table is searched to see if the FEC with destination IP prefix and COS has been set (708).

Subsequently, it is determined whether the FEC corresponding to the new data flow has already been assigned (709), and if it is already assigned, it is determined to be of the same class as the existing FEC, and the label assigned to the existing FEC is mapped (711). If not, a new FEC is determined and a new label is mapped (710).

On the other hand, it is determined whether there is an error (704), and if there is no error, the FEC-TLV in the label mapping message received from the counterpart LSR is analyzed (705), and if the FEC type is specified as an IP prefix, the new FEC is determined and the new FEC is determined. Map the label (710) and end.

As described in detail above, in the ATM-based MPLS of the present invention, a method for providing differentiated services according to FEC can increase scalability than a method for configuring FEC for each data flow, and provides a differentiated service when assigning FEC to an IP prefix. It can solve the problem of not providing.

In addition, it is possible to correspond to the ATM Transfer Capability appropriate to the traffic characteristics of the granted FECs, thereby ensuring the quality of service through the traffic control function provided by ATM.

In the above description, the technical concept of the differentiated service providing method according to the FEC in the ATM-based MPLS of the present invention has been described with the accompanying drawings, but this is only illustrative of the best embodiments of the present invention and is not intended to limit the present invention. . In addition, it is obvious that any person skilled in the art can make various modifications and imitations without departing from the scope of the technical idea of the present invention.

Claims (3)

In the differentiated service providing method applied to ATM-based MPLS, A first step of receiving an Internet packet and analyzing a destination address and a class of service; A second step of judging whether there is a forward equality level in accordance with the new Internet data flow in the existing stream that has been determined; A third step of mapping to a label that already exists as a result of the determination of the second step; A fourth step of establishing a LDP session with the counterpart LSR in order to map a label by determining a new forward equal rank if it does not exist as a result of the determination of the second step; A fifth step of transmitting a label request message to a counterpart LSR through an established LDP session; And And a sixth step of receiving a label mapping message from the counterpart LSR, binding the mapped label, and storing the mapped label. In the differentiated service providing method applied to ATM-based MPLS, A first step of establishing an LDP session with a counterpart LSR and analyzing the FEC-TLV of the received label mapping message; A second step of analyzing the COS-TLV in the label mapping message if the FEC type is defined to give an FEC for the data flow as a result of the first step analysis; A third step of searching the forward information table to determine whether an FEC corresponding to the new data flow has already been granted; A fourth step of mapping the label given to the existing FEC by determining the same level as the existing FEC if it is given as a result of the determination of the third step, and determining a new FEC and mapping a new label if it is not given; And And a fifth step of determining a new FEC and mapping a new label when the FEC type is designated as an IP prefix as a result of the analysis of the first step. On your computer, In the differentiated service providing method applied to ATM-based MPLS, A first step of establishing an LDP session with a counterpart LSR and analyzing the FEC-TLV of the received label mapping message; A second step of analyzing the COS-TLV in the label mapping message if the FEC type is defined to give an FEC for the data flow as a result of the first step analysis; A third step of searching the forward information table to determine whether an FEC corresponding to the new data flow has already been granted; A fourth step of mapping the label given to the existing FEC by determining the same level as the existing FEC if it is given as a result of the determination of the third step, and determining a new FEC and mapping a new label if it is not given; And And recording a program capable of executing a fifth step of determining a new FEC and mapping a new label when the FEC type is designated as an IP prefix as a result of the analysis in the first step.