CN106817434B

CN106817434B - Session binding method, routing agent and PCRF

Info

Publication number: CN106817434B
Application number: CN201510857325.6A
Authority: CN
Inventors: 黄震宁; 朱琳
Original assignee: China Mobile Communications Group Co Ltd
Current assignee: China Mobile Communications Group Co Ltd
Priority date: 2015-11-30
Filing date: 2015-11-30
Publication date: 2020-02-18
Anticipated expiration: 2035-11-30
Also published as: CN106817434A

Abstract

The invention discloses a session binding method, which comprises the following steps: a first LDRA receives a first Rx interface request message; when the first Rx interface request message is determined not to carry the destination PCRF identification, matching a first corresponding relation table configured locally, locally stored Gx interface session information and user public network IP address information carried in the first Rx interface request message; the first corresponding relation table is a corresponding relation table of the user public network IP address and the PCEF in the first LDRA tandem area; when the first matching relation is obtained, session binding is carried out; filling the PCEF identification corresponding to the first matching relationship and the corresponding PCRF identification in the Rx interface request message to obtain a second Rx interface request message; the corresponding PCEF identifier is used for session binding of the corresponding PCRF; and routing the second Rx interface request message according to the corresponding PCRF identification. The invention also discloses an LDRA, an HDRA and a PCRF.

Description

Session binding method, routing agent and PCRF

Technical Field

The present invention relates to the field of wireless communications, and in particular, to a session binding method, a routing Agent (DRA), and a Policy and Charging Rule Function (PCRF).

Background

In order to achieve the goal of differentiated Service capability, resource grooming capability, network traffic optimization capability, etc., a Policy and Charging Control (PCC) system architecture is introduced into the existing packet network to perform Quality of Service (QoS) Control on packet data services according to the standard specification of the third Generation Partnership Project (3 GPP).

At present, a method for associating users under a PCC architecture, that is, performing session binding, mainly includes: by adopting the binding scheme of the private network IP address and the public network IP address of the user, the pairing of all the public network IP addresses and the corresponding relation of a Policy and Charging Enforcement Function (PCEF) is required to be carried out on the DRA side, so that the processing overhead of the DRA is greatly increased.

Disclosure of Invention

In order to solve the existing technical problem, embodiments of the present invention provide a session binding method, a DRA, and a PCRF.

In order to achieve the above purpose, the technical solution of the embodiment of the present invention is realized as follows:

the embodiment of the invention provides a session binding method, which is applied to a routing agent (LDRA) of a first visit place, and comprises the following steps:

receiving a first Rx interface request message;

when the first Rx interface request message is determined not to carry the destination PCRF identification, matching a first corresponding relation table configured locally, locally stored Gx interface session information and user public network IP address information carried in the first Rx interface request message; the first corresponding relation table is a corresponding relation table of the user public network IP address and the PCEF in the first LDRA tandem area;

when the first matching relation is obtained, session binding is carried out;

filling the PCEF identification corresponding to the first matching relationship and the corresponding PCRF identification in the first Rx interface request message to obtain a second Rx interface request message; the corresponding PCEF identifier is used for session binding of the corresponding PCRF;

and routing the second Rx interface request message according to the corresponding PCRF identification so as to transmit the second Rx interface request message to the corresponding PCRF.

In the above scheme, the method further comprises:

and when the user is activated, recording the PCRF identification, the PCEF identification and the private network IP address information corresponding to the user to form Gx interface session information.

In the above scheme, the session binding is as follows:

and carrying out session binding by utilizing the corresponding PCEF identifier and the private network IP address of the user.

In the above scheme, the method further comprises:

matching the first corresponding relation table, the locally stored Gx interface session information and the user IP address information carried in the first Rx interface request message, and matching according to a locally configured second corresponding relation table when the first matching relation is not obtained; the second corresponding relation table is a corresponding relation table between the user public network IP address in the first LDRA adjacent tandem area and the adjacent direct-connected LDRA;

and when a second matching relationship is obtained, sending the first Rx interface request message to an adjacent LDRA corresponding to the second matching relationship so as to enable the adjacent LDRA to perform session binding, and transmitting the corresponding Rx interface request message to the corresponding PCRF.

In the above scheme, the method further comprises:

and when the second matching relation is not obtained, sending the first Rx interface request message to a home routing agent (HDRA) so that the HDRA sends the first Rx interface request message to a second LDRA.

The embodiment of the invention also provides a session binding method which is applied to the first HDRA, and the method comprises the following steps:

receiving a first Rx interface request message sent by a first LDRA;

and according to the user public network IP address carried in the first Rx interface request message, sending the first Rx interface request message to a corresponding second LDRA so as to enable the second LDRA to perform session binding, and transmitting the corresponding Rx interface request message to a corresponding PCRF, or sending the first Rx interface request message to a corresponding second HDRA so as to enable the second HDRA to distribute the corresponding LDRA or HDRA for the first Rx interface request message.

In the above scheme, the sending the first Rx interface request message to the corresponding second LDRA according to the user public network IP address carried in the first Rx interface request message is:

matching a third corresponding relation table configured locally with the user public network IP address carried in the first Rx interface request message to obtain a third matching relation; the third corresponding relation table is the corresponding relation between the user public network IP address and the LDRA;

and sending the first Rx interface request message to the second LDRA according to the third matching relation.

In the above scheme, the sending the first Rx interface request message to the corresponding second HDRA according to the user public network IP address carried in the first Rx interface request message is:

matching a locally configured fourth corresponding relation table with the user public network IP address carried in the first Rx interface request message to obtain a fourth matching relation; the fourth corresponding relation table is the corresponding relation between the IP address of the user public network and the HDRA;

and sending the first Rx interface request message to the second HDRA according to the fourth matching relation.

The embodiment of the invention also provides a session binding method, which is applied to the PCRF and comprises the following steps:

receiving a second Rx interface request message;

and carrying out session binding according to the PCEF identification in the second Rx interface request message and the IP address information of the private network of the user.

In the above scheme, the method further comprises:

and triggering corresponding policy decision after the session is bound.

An embodiment of the present invention further provides an LDRA, including: the device comprises a first receiving unit, a first matching unit, a first session binding unit, a filling unit and a first sending unit; wherein the content of the first and second substances,

the first receiving unit is configured to receive a first Rx interface request message;

the first matching unit is configured to, when it is determined that the first Rx interface request message does not carry the destination policy control and charging rule function entity PCRF identifier, match a locally configured first correspondence table, locally stored Gx interface session information, and user public network IP address information carried in the first Rx interface request message; the first corresponding relation table is a corresponding relation table of the user public network IP address and the PCEF in the LDRA convergence area;

the first session binding unit is used for carrying out session binding when a first matching relationship is obtained;

the filling unit is configured to fill the PCEF identifier and the PCRF identifier corresponding to the first matching relationship in the Rx interface request message to obtain a second Rx interface request message; the corresponding PCEF identifier is used for session binding of the corresponding PCRF;

the first sending unit is configured to route the second Rx interface request message according to the corresponding PCRF identifier, so that the second Rx interface request message is transmitted to the corresponding PCRF.

In the foregoing solution, the LDRA further includes: and the recording unit is used for recording the PCRF identification, the PCEF identification and the private network IP address information corresponding to the user when the user is activated to form Gx interface session information.

In the foregoing solution, the LDRA further includes: a second matching unit, configured to match the first correspondence table, locally stored Gx interface session information, and user IP address information carried in the first Rx interface request message, and perform matching according to a locally configured second correspondence table when the first matching relationship is not obtained; the second corresponding relation table is a corresponding relation table of the user public network IP address in the adjacent tandem area of the LDRA and the adjacent direct-connected LDRA;

the first sending unit is further configured to send the first Rx interface request message to an adjacent LDRA corresponding to a second matching relationship when the second matching relationship is obtained, so that the adjacent LDAR performs session binding, and transmit a corresponding Rx interface request message to the corresponding PCRF.

In the foregoing scheme, the first sending unit is further configured to send the first Rx interface request message to the HDRA when the second matching relationship is not obtained, so that the HDRA sends the first Rx interface request message to the second LDRA.

An embodiment of the present invention further provides an HDRA, including: a second receiving unit and a second transmitting unit; wherein the content of the first and second substances,

the second receiving unit is configured to receive a first Rx interface request message sent by the first LDRA;

the second sending unit is configured to send the first Rx interface request message to a corresponding second LDRA according to a user public network IP address carried in the first Rx interface request message, so that the second LDRA performs session binding, and transmits the corresponding Rx interface request message to a corresponding PCRF, or send the first Rx interface request message to a corresponding second HDRA, so that the second HDRA allocates the corresponding LDRA or HDRA to the first Rx interface request message.

In the foregoing solution, the HDRA further includes: a third matching unit, configured to match a locally configured third correspondence table with the user public network IP address carried in the first Rx interface request message, to obtain a third matching relationship; the third corresponding relation table is the corresponding relation between the user public network IP address and the LDRA;

correspondingly, the second sending unit is configured to send the first Rx interface request message to the second LDRA according to the third matching relationship.

In the foregoing solution, the HDRA further includes: a fourth matching unit, configured to match a locally configured fourth correspondence table with the user public network IP address carried in the first Rx interface request message, to obtain a fourth matching relationship; the fourth corresponding relation table is the corresponding relation between the IP address of the user public network and the HDRA;

correspondingly, the second sending unit is configured to send the first Rx interface request message to the second HDRA according to the fourth matching relationship.

An embodiment of the present invention further provides a PCRF, including: a third receiving unit and a second session binding unit; wherein the content of the first and second substances,

the third receiving unit is configured to receive a second Rx interface request message;

and the second session binding unit is used for carrying out session binding according to the PCEF identifier in the second Rx interface request message and the IP address information of the private network of the user.

In the foregoing solution, the PCRF further includes: a policy decision unit; wherein the content of the first and second substances,

the second session binding unit is also used for triggering the strategy decision unit after the session binding;

the strategy decision unit is used for carrying out corresponding strategy decision.

According to the session binding method, the DRA and the PCRF provided by the embodiment of the invention, the first LDRA receives a first Rx interface request message; when the first Rx interface request message is determined not to carry the destination PCRF identification, matching a first corresponding relation table configured locally, locally stored Gx interface session information and user public network IP address information carried in the first Rx interface request message; the first corresponding relation table is a corresponding relation table of the user public network IP address and the PCEF in the first LDRA tandem area; when the first matching relation is obtained, session binding is carried out; filling the PCEF identification corresponding to the first matching relationship and the corresponding PCRF identification in the first Rx interface request message to obtain a second Rx interface request message; the corresponding PCEF identifier is used for session binding of the corresponding PCRF; routing the second Rx interface request message according to the corresponding PCRF identification; and after receiving the second Rx interface request message, the corresponding PCRF performs session binding according to the PCEF identifier in the second Rx interface request message and the IP address information of the private network of the user, and the LDRA only performs pairing of the corresponding relation between the IP address of the public network of the user and the PCEF in the local convergence region, so that the processing overhead of the LDRA can be greatly reduced. Meanwhile, the user association, namely the session binding, can be realized under the condition that the IP address of the user private network is repeated.

In addition, the first HDRA receives a first Rx interface request message sent by the first LDRA; and according to the user public network IP address carried in the first Rx interface request message, the first Rx interface request message is sent to a corresponding second LDRA, so that the second LDRA performs session binding, and the corresponding Rx interface request message is transmitted to a corresponding PCRF, or the first Rx interface request message is sent to a corresponding second HDRA, so that the second HDRA allocates the corresponding LDRA or HDRA for the first Rx interface request message, and the HDRA does not need to record session binding information, so that the overhead of the HDRA is greatly reduced, and the modification difficulty is reduced.

Drawings

In the drawings, which are not necessarily drawn to scale, like reference numerals may describe similar components in different views. Like reference numerals having different letter suffixes may represent different examples of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed herein.

Fig. 1 is a schematic diagram of a PCC architecture in the related art;

FIG. 2 is a flow chart illustrating a method for implementing user association in the related art;

fig. 3 is a flowchart illustrating a session binding method at a first LDRA side according to an embodiment of the present invention;

fig. 4 is a flowchart illustrating a session binding method at a first HDRA side according to an embodiment of the present invention;

fig. 5 is a schematic flowchart of a session binding method at a PCRF side in an embodiment of the present invention;

FIG. 6 is a flowchart illustrating a second session binding method according to an embodiment of the present invention;

fig. 7 is a corresponding relationship representation intention configured on LDRA and HDRA according to the second embodiment of the present invention;

FIG. 8 is a schematic structural diagram of a third LDRA according to an embodiment of the present invention;

FIG. 9 is a schematic structural diagram of a third HDRA according to an embodiment of the present invention;

fig. 10 is a schematic diagram of a PCRF structure according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

Prior to describing embodiments of the present invention, a related art will be understood.

Fig. 1 is a schematic diagram of a PCC architecture. As can be seen from fig. 1, the main network elements in the PCC architecture include: PCRF, PCEF, Application Function entity (AF), Online Charging System/Offline Charging System (OCS/OFCS), and subscription Repository (SPR). Wherein, the functions of each network element are respectively as follows:

PCRF: with policy control decision making and flow-based charging control functionality, the PCEF is provided with network control functions with respect to traffic data flow detection, gating, QoS-based and flow-based charging (except credit control).

A PCEF: the charging function responsible for detecting service data flow, executing policy and based on flow is generally set on Gateway GPRS Support Node (GGSN) or PDN Gateway (P-GW).

AF: the dynamic policy/charging control is mainly carried out on the IP-CAN user plane behavior and is arranged on a service platform.

SPR: the service server is a logical entity and is used for storing information related to all subscribers or subscriptions, including services allowed by the subscribers and the like.

OCS/OFCS: for online/offline charging.

Under the PCC architecture, on one hand, it is considered that IP addresses allocated to users at the present stage are private network IP addresses, so that an IP address duplication problem (IPv4 address) exists under different P-GWs, and therefore, the user association cannot be realized in an international standard manner (using the IP addresses allocated to users). On the other hand, considering that the private network IP addresses of each user under the same P-GW do not overlap, at present, user association is mainly performed through the user public and private network IP addresses, that is, the private network IP address allocated to the user and the public network IP address (the P-GW that can determine the user's home) of the user behind the NET are used for user association.

Specifically, as shown in fig. 2, the process of implementing user association mainly includes the following steps:

step 201: on the established PDN connection, UE initiates a hypertext Transfer Protocol (HTTP) request to AF through PCEF;

step 202: after receiving the HTTP request, the PCEF and the determined PCRF interact to finish authorization of the user session corresponding to the UE;

specifically, the PCEF sends a Credit Control Request (CCR, Credit Control Request) to the PCRF through the DRA;

the PCRF sends a Credit Control Answer (CCA) to the PCEF via the DRA.

Step 203: after receiving an HTTP request sent by UE to AF, when P-GW determines that the IP address allocated to UE is a private IP address, inserting the private IP address information of UE into the header of HTTP request message of the message;

here, in practical application, the P-GW may also insert a Public Land Mobile Network (PLMN) Identity (ID) corresponding to the selected PCRF into a header of the HTTP request message.

Step 204: and the P-GW forwards the modified HTTP request message to the AF requested by the UE.

Here, since the PCEF is generally combined with the P-GW, it is the PCEF that performs steps 201 to 202, and it is the P-GW that performs steps 203 to 204.

Step 205: after receiving the HTTP request message, the AF carries out addressing of the access node according to the additional information of the HTTP packet header;

here, the additional information may be PLMN ID information. If the PLMN ID information cannot be directly obtained, the AF may calculate the corresponding PLMN ID information according to the public network IP address information of the UE in the additional information.

In practical application, the access node may be an Application Access Control (AAC) node, or may be a service creation environment entity (SCEF).

Assuming that the access node is AAC, the access node addressing procedure includes:

the AF constructs AAC Domain Name information according to PLMN ID information of a user access point, and sends DNS query information to a Domain Name System (DNS);

after receiving the message, the DNS queries the IP address information of the AAC according to the information stored in the DNS, and returns a DNS response message carrying the AACIP address to the AF.

Wherein, the DNS inquiry message carries AAC domain name information.

The DNS response message carries the IP address of AAC.

Step 206: the AF initiates an HTTP session message to an AAC node corresponding to the IP address of the inquired AAC;

here, the initiated session message carries the public network IP address and the private network IP address information of the user, so as to help the AAC node find a suitable PCRF.

Step 207: after receiving the session message, the AAC node finds out a proper PCRF according to the public network IP address and the private network IP address information of the user, and the PCRF performs session binding according to the public network IP address and the private network IP address information of the user.

Specifically, an AAC node sends an authentication authorization Request-Initial Request (AAR-I, AA-Request-Initial) Request to a corresponding PCRF through a DRA;

and after receiving the request, the PCRF performs session binding and returns an AAA-I message to the AAC node through the DRA.

The sent AAR-I request carries information of a public network IP address and a private network IP address of a user, the DRA matches the public network IP address of the user with corresponding relations between all public network IP addresses configured by the DRA and the PCEF so as to help the AAC node to find a proper PCRF, and the received AAR-I request is sent to the found proper PCRF.

Wherein, after receiving AAA-I, DRA needs to record session binding information.

As can be seen from the above description, in the PCRF addressing process, when a Diameter signaling network is used to carry Gx and Rx interface messages, the DRA needs to pair all public network IP addresses with the PCEF, and in addition, the DRA also needs to perform session binding to find a suitable PCRF, which greatly increases the processing overhead of the DRA, thereby resulting in a large network overhead.

Based on this, in various embodiments of the invention: a first visited routing agent (LDRA) receiving a first Rx interface request message; when the first Rx interface request message is determined not to carry the destination PCRF identification, matching a first corresponding relation table configured locally, locally stored Gx interface session information and user public network IP address information carried in the first Rx interface request message; the first corresponding relation table is a corresponding relation table of the user public network IP address and the PCEF in the first LDRA tandem area; when the first matching relation is obtained, session binding is carried out; filling the PCEF identification corresponding to the first matching relationship and the corresponding PCRF identification in the first Rx interface request message to obtain a second Rx interface request message; the corresponding PCEF identifier is used for session binding of the corresponding PCRF; routing the second Rx interface request message according to the corresponding PCRF identification; and after receiving the second Rx interface request message, the corresponding PCRF performs session binding according to the PCEF identifier in the second Rx interface request message and the IP address information of the private network of the user.

Example one

The present embodiment provides a session binding method, applied to a first LDRA, as shown in fig. 3, the method includes the following steps:

step 301: receiving a first Rx interface request message;

here, in actual application, when a user performs a service, the user applies for a service request to an access node (such as an AAC node or SCEF), and at this time, a service request message received by the access node may be from a client of the User (UE), that is, a service request message sent by the UE, or may be a service request message sent by a service platform (AF). Whether the service request message is sent to the access node by the user himself or by the service platform can be determined according to the requirements of the service type.

The service request message carries public network IP address information, private network IP address information and service request information of the user.

After receiving the service request message, the access node triggers a first Rx interface request message to apply for a strategy to a core network; the first Rx interface request message (e.g., AAR-I message) carries the public network IP address information and the private network IP address information of the user.

Before performing this step, the method may further include:

The PCRF identifier may be a PCRF host name (host); accordingly, the PCEF identification may be PCEFhost.

In practical applications, the PCEF host is a source (origin) host in a user session establishment Request message (such as a Credit Control Initial Request (CCR-I) message).

The PCRF host may be a PCRF host used when the PCRF is locally selected, or may be a PCRF host extracted from an origin host field of a response message (e.g., a Credit Control Answer (CCA-I) message).

Step 302: when the first Rx interface request message is determined not to carry the destination PCRF identification, matching a first corresponding relation table configured locally, locally stored Gx interface session information and user public network IP address information carried in the first Rx interface request message;

here, the first correspondence table is a correspondence table between the user public network IP address in the first LDRA tandem area and the PCEF.

In the first mapping table, the expression form of the public network IP address may be an IP address field, an independent IP address, or a class of IP addresses represented by a mask.

In the first corresponding relation table, the DRA and the PCRF support the determination of the corresponding relation between the PCEF identifier and the PCEF host by identifying the PCEF identifier.

Here, the PCEF identity may be a PCEF host, or may be a abbreviation of the PCEF host or another form, and in the embodiment of the present invention, the PCEF identity is not limited, and in actual application, as long as the information capable of identifying the identity of the PCEF can be used as the PCEF identity.

It should be noted that: the embodiment of the invention does not limit the specific implementation process that the DRA and the PCRF support the determination of the corresponding relationship between the PCEF identity and the PCEF host by identifying the PCEF identity, and can be any implementation process, such as identification by identifying the PCEF prefix.

In actual application, after receiving the first Rx interface request message, the first LDRA may query whether the first Rx interface request message carries a destination PCRF identifier (for example, Dest-host), and when the first Rx interface request message carries the destination PCRF identifier, the first Rx interface request message may be routed according to the destination PCRF until the first Rx interface request message is transmitted to the destination PCRF.

Step 303: when the first matching relation is obtained, session binding is carried out;

specifically, session binding is performed by using the PCEF identifier corresponding to the first matching relationship and the private network IP address of the user.

Step 304: filling the PCEF identification corresponding to the first matching relationship and the corresponding PCRF identification in the first Rx interface request message to obtain a second Rx interface request message; the corresponding PCEF identifier is used for session binding of the corresponding PCRF;

step 305: and routing the second Rx interface request message according to the corresponding PCRF identification so as to transmit the second Rx interface request message to the corresponding PCRF.

Here, when the first mapping relationship table, the locally stored Gx interface session information, and the user IP address information carried in the first Rx interface request message are matched, and a first matching relationship is not obtained, the first LDRA performs matching according to a locally configured second mapping relationship table; the second corresponding relation table is a corresponding relation table between the user public network IP address in the first LDRA adjacent tandem area and the adjacent direct-connected LDRA;

and when a second matching relationship is obtained, the first LDRA sends the first Rx interface request message to an adjacent LDRA corresponding to the second matching relationship, so that the adjacent LDRA performs session binding, and transmits the corresponding Rx interface request message to the corresponding PCRF.

In other words, steps 302-305 are performed by the neighboring LDRA.

Specifically, the adjacent LDRA matches the locally stored Gx interface session information with the user public network IP address information carried in the first Rx interface request message according to the correspondence table between the user public network IP address in the locally configured self-tandem area and the policy control and charging enforcement function entity PCEF; and when the matching is available, the adjacent LDAR performs session binding, fills the PCEF identification corresponding to the matching relation and the corresponding PCRF identification in the first Rx interface request message, and routes the filled first Rx interface request message according to the corresponding PCRF identification so as to transmit the Rx interface request message to the corresponding PCRF.

When the second matching relationship is not obtained, the first LDRA sends the first Rx interface request message to a home routing agent (HDRA), so that the HDRA sends the first Rx interface request message to a second LDRA, and the second LDRA performs the above operation of the first LDRA, thereby finally transmitting the Rx interface request message to the corresponding PCRF.

The embodiment also provides a session binding method applied to the first HDRA, as shown in fig. 4, the method includes the following steps:

step 401: receiving a first Rx interface request message sent by a first LDRA;

step 402: and according to the user public network IP address carried in the first Rx interface request message, sending the first Rx interface request message to a corresponding second LDRA so as to enable the second LDRA to perform session binding, and transmitting the corresponding Rx interface request message to a corresponding PCRF, or sending the first Rx interface request message to a corresponding second HDRA so as to enable the second HDRA to distribute the corresponding LDRA or HDRA for the first Rx interface request message.

Specifically, the first HDRA matches a locally configured third correspondence table with the user public network IP address carried in the first Rx interface request message to obtain a third matching relationship; the third corresponding relation table is the corresponding relation between the user public network IP address and the LDRA;

Or, the first HDRA matches a locally configured fourth correspondence table with the user public network IP address carried in the first Rx interface request message to obtain a fourth matching relationship; the fourth corresponding relation table is the corresponding relation between the IP address of the user public network and the HDRA;

In practical application, because the first HDRA further has a routing function, after receiving the first Rx interface request message, first, it is queried whether a destination PCRF identifier (for example, Dest-host) is carried in the first Rx interface request message, and when the destination PCRF identifier is carried in the first Rx interface request message, the first Rx interface request message is routed according to the destination PCRF until the first Rx interface request message is transmitted to the destination PCRF.

The specific operation process of the second LDRA is completely the same as the steps 302 to 305, and is not described herein again.

The specific processing procedure of the second HDRA is completely the same as that of the first HDRA, and is not described again.

The embodiment also provides a session binding method, which is applied to the PCRF, and as shown in fig. 5, the method includes the following steps:

step 501: receiving a second Rx interface request message;

step 502: and carrying out session binding according to the PCEF identification in the second Rx interface request message and the IP address information of the private network of the user.

Here, in actual application, when the second Rx interface request message corresponds to an Rx interface new call, the PCRF may perform step 502, and when the second Rx interface request message corresponds to a non-Rx interface new call, the PCRF may perform session binding according to a session ID in the second Rx interface request message, where a specific processing procedure may refer to the prior art.

After the session is bound, a corresponding policy decision is triggered.

In the session binding method provided in this embodiment, a first LDRA receives a first Rx interface request message; when the first Rx interface request message is determined not to carry the destination PCRF identification, matching a first corresponding relation table configured locally, locally stored Gx interface session information and user public network IP address information carried in the first Rx interface request message; the first corresponding relation table is a corresponding relation table of the user public network IP address and the PCEF in the first LDRA tandem area; when the first matching relation is obtained, session binding is carried out; filling the PCEF identification corresponding to the first matching relationship and the corresponding PCRF identification in the first Rx interface request message to obtain a second Rx interface request message; the corresponding PCEF identifier is used for session binding of the corresponding PCRF; routing the second Rx interface request message according to the corresponding PCRF identification; and after receiving the second Rx interface request message, the corresponding PCRF performs session binding according to the PCEF identifier in the second Rx interface request message and the IP address information of the private network of the user, and the LDRA only performs pairing of the corresponding relation between the IP address of the public network of the user and the PCEF in the local convergence region, so that the processing overhead of the LDRA can be greatly reduced. Meanwhile, the user association, namely the session binding, can be realized under the condition that the IP address of the user private network is repeated.

In addition, the first HDRA matches a locally configured third correspondence table with the user public network IP address carried in the first Rx interface request message to obtain a third matching relationship; the third corresponding relation table is the corresponding relation between the user public network IP address and the LDRA; according to the third matching relation, the first Rx interface request message is sent to the second LDRA; or, the first HDRA matches a locally configured fourth correspondence table with the user public network IP address carried in the first Rx interface request message to obtain a fourth matching relationship; the fourth corresponding relation table is the corresponding relation between the IP address of the user public network and the HDRA; and according to the fourth matching relationship, the first Rx interface request message is sent to the second HDRA, and the HDRA only performs the pairing of the corresponding relationship between the user public network IP address and the LDRA or the pairing between the user public network IP address and the HDRA, so that the processing overhead of the HDRA can be greatly reduced, and the reconstruction difficulty is further reduced.

Example two

On the basis of the first embodiment, the present embodiment describes in detail how to perform session binding.

In this embodiment, the access node is an AAC node.

As shown in fig. 6, the session binding process mainly includes the following steps:

step 601: configuring corresponding relation tables on the LDRA and the HDRA, and then executing a step 601;

specifically, a corresponding relation table of a user public network IP address and an LDRA (Low-density random Access) and a corresponding relation table of the user public network IP address and the HDRA are configured on the HDRA; and configuring a corresponding relation table between the user public network IP address in the junction region and the PCEF on the LDRA, and simultaneously configuring a corresponding relation table between the user public network IP address in the adjacent junction region and the adjacent direct-connected LDRA on the LDRA.

The corresponding correspondence table configured on LDRA and HDRA may be as shown in fig. 7.

The expression form of the public network IP address can be an IP address section, an independent IP address or a class of IP addresses represented by masks.

In practical application, the table for mapping the user public network IP address to the PCEF in the tandem area configured on the LDRA may be a PCEF list, instead of the mapping shown in fig. 7. Meanwhile, the DRA and the PCRF support the judgment of the corresponding relation between the PCEF identification and the PCEF host by identifying the PCEF identification.

The PCEF identity may be a PCEF host, or may be a shorthand or other means of the PCEF host, and in the embodiment of the present invention, the PCEF identity is not limited, and in actual application, information that can identify the identity of the PCEF may be used as the PCEF identity.

Step 602: when a user is activated, recording PCRF identification, PCEF identification and private network IP address information corresponding to the user;

here, these pieces of recorded information form Gx interface session information.

The PCRF identifier may be a PCRF host; accordingly, the PCEF identification may be a PCEF host.

In practice, the PCEF host is originhost in a user session establishment request message (such as a CCR-I message).

The PCRF host may be a PCRF host used when the PCRF is locally selected, or may be a PCRF host extracted from an origin host field of a response message (such as a CCA-I message).

Step 603: when a user carries out a service, applying for a service request to an AAC node;

here, the service request message received by the AAC node may be from a client of the User (UE), that is, a service request message sent by the UE, or may be a service request message sent by a service platform (AF). Whether the service request message is sent by the user himself to the AAC node or by the service platform to the AAC node can be determined according to the needs of the service type.

Step 604: after receiving the service request message, the AAC node triggers an Rx interface request message to apply for a strategy to a core network;

here, the Rx interface cancel request message (e.g., AAR-I message) carries the public network IP address information and the private network IP address information of the user.

Step 605: after receiving the Rx interface request message, the LDRA queries whether the Rx interface request message carries a Dest-host, if so, performs step 615, otherwise, performs step 606;

step 606: matching the corresponding relation table of the user public network IP address and the PCEF in the locally configured local tandem area, the locally stored Gx interface session information and the user public network IP address information carried in the Rx interface request message; judging whether a first matching relation is obtained, if so, executing a step 614, otherwise, executing a step 607;

step 607: matching the corresponding relation table of the user public network IP address and the adjacent direct-connected LDRA in the adjacent tandem area configured locally with the user public network IP address information carried in the Rx interface request message; judging whether a second matching relation is obtained, if so, executing step 608, otherwise, executing step 610;

step 608: sending the Rx interface request message to an adjacent LDRA;

step 609: after receiving the Rx interface request message, the adjacent LDRA queries whether the Rx interface request message carries a Dest-host, if so, performs step 615, otherwise, performs step 606;

here, in actual application, the operations performed by each LDRA are the same, that is, after receiving the Rx interface request message, first query whether the Rx interface request message carries a Dest-host, if so, execute step 615, otherwise, execute step 606.

In practical application, the number of adjacent LDRAs of each LDRA is relatively small, and when the adjacent LDRAs match the locally configured corresponding relationship table between the user public network IP address and PCEF in the local tandem area, the locally stored Gx interface session information, and the user public network IP address information carried in the Rx interface request message, and no matching relationship is obtained, the last adjacent LDRA directly sends the Rx interface request message to the corresponding HDRA, and the HDRA determines the corresponding LDRA or HDRA.

Step 610: sending the Rx interface request message to a corresponding HDRA;

step 611: after receiving the Rx interface request message, the corresponding HDRA queries whether the Rx interface request message carries a Dest-host, if so, performs step 615, otherwise, performs step 612;

here, since the HDRA also has a routing function, after receiving the Rx interface request message, it will first determine whether the Rx interface request message carries a Dest-host, and if so: and routing the Rx interface request message according to the Dest-host.

Step 612: the HDRA matches the corresponding relation between the locally configured user public network IP address and the L/HDRA with the user public network IP address carried in the Rx interface request message;

step 613: if the corresponding LDRA is matched, sending an Rx interface request message to the corresponding LDRA, executing steps 605-608 and 614-615 by the corresponding LDRA, if the corresponding HDRA is matched, sending the Rx interface request message to the corresponding HDRA, and executing step 612 by the corresponding HDRA;

step 614: carrying out session binding; filling the PCEF identification corresponding to the matching relation and the corresponding PCRF identification into an Rx interface request message;

here, session binding is performed using the corresponding PCEF identity and the private network IP address of the user.

In actual application, the PCEF identifier may be filled in by replacing the value of the original field carrying the public network IP address information, or by using a new field carrying the PCEF identifier information.

And filling the corresponding PCRF identification in the Rx interface request message, in other words, filling the desthost field information in the Rx interface request message.

Step 615: routing the Rx interface request message according to the Dest-host until the Rx interface request message is transmitted to the destination PCRF;

step 616: and after receiving the Rx interface request message, the PCRF performs session binding, triggers a corresponding policy decision and ends the current processing flow.

Specifically, when the Rx interface request message received corresponds to an Rx interface new call, the PCRF performs session binding according to the PCEF identifier in the Rx interface request message and the user private network IP address information; and when the Rx interface request message corresponds to a new call not returned by the Rx interface, the PCRF performs session binding according to the session ID in the Rx interface request message.

As can be seen by combining the session binding flows shown in fig. 2 and fig. 6, if the scheme of public network IP address + private network IP address is used, on one hand, it is necessary that the LDRA, the HDRA, and the PCRF all need to record session binding information; on the other hand, mapping tables of all public network IP addresses and PCEF identifiers need to be configured, so that pairing of all public network IP addresses and PCEF corresponding relations is performed by the DRA, and processing overhead of the DRA is greatly increased. The two aspects are integrated, so that the conventional scheme has more reconstructed network elements and high performance overhead of each network element. Meanwhile, the DRA is used as a core node of a signaling network, and the reconstruction difficulty is very high.

By adopting the session binding scheme of the embodiment of the invention, the LDRA only performs the pairing of the corresponding relation between the user public network IP address and the PCEF in the tandem area, and the HDRA does not need to record the session binding information, thereby greatly reducing the processing overhead of the LDRA. Meanwhile, the user association, namely the session binding, can be realized under the condition that the IP address of the user private network is repeated.

EXAMPLE III

To implement the method according to the embodiment of the present invention, this embodiment provides an LDRA, as shown in fig. 8, where the LDRA includes: a first receiving unit 81, a first matching unit 82, a first session binding unit 83, a filling unit 84, and a first sending unit 85; wherein the content of the first and second substances,

the first receiving unit 81 is configured to receive a first Rx interface request message;

the first matching unit 82 is configured to, when it is determined that the first Rx interface request message does not carry the destination policy control and charging rule function entity PCRF identifier, match a first locally configured correspondence table, locally stored Gx interface session information, and user public network IP address information carried in the first Rx interface request message; the first corresponding relation table is a corresponding relation table of the user public network IP address and the PCEF in the LDRA convergence area;

the first session binding unit 83 is configured to perform session binding when the first matching relationship is obtained;

the filling unit 84 is configured to fill the PCEF identifier corresponding to the first matching relationship and the corresponding PCRF identifier in the Rx interface request message to obtain a second Rx interface request message; the corresponding PCEF identifier is used for session binding of the corresponding PCRF;

the first sending unit 85 is configured to route the second Rx interface request message according to the corresponding PCRF identifier, so that the second Rx interface request message is transmitted to the corresponding PCRF.

In practical application, when a user performs a service, the user applies for a service request to an access node (such as an AAC node or SCEF), and at this time, a service request message received by the access node may be from a client of the User (UE), that is, a service request message sent by the UE, or may be a service request message sent by a service platform (AF). Whether the service request message is sent to the access node by the user himself or by the service platform can be determined according to the requirements of the service type.

Here, the service request message carries public network IP address information, private network IP address information, and service request information of the user.

In an embodiment, the LDRA may further include: and the recording unit is used for recording the PCRF identification, the PCEF identification and the private network IP address information corresponding to the user when the user is activated to form Gx interface session information.

In actual application, after the first receiving unit 81 receives the first Rx interface request message, the first matching unit 82 may query whether the first Rx interface request message carries a destination PCRF identifier (for example, Dest-host), and when the first Rx interface request message carries the destination PCRF identifier, the first sending unit 85 may route the first Rx interface request message according to the destination PCRF until the first Rx interface request message is transmitted to the destination PCRF.

The first session binding unit 83 is specifically configured to: and carrying out session binding by utilizing the PCEF identifier corresponding to the first matching relationship and the private network IP address of the user.

In an embodiment, the LDRA may further include: a second matching unit, configured to match, by the first matching unit 82, the first mapping table, locally stored Gx interface session information, and user IP address information carried in the first Rx interface request message, and perform matching according to a locally configured second mapping table when the first matching relationship is not obtained; the second corresponding relation table is a corresponding relation table of the user public network IP address in the adjacent tandem area of the LDRA and the adjacent direct-connected LDRA;

the first sending unit 85 is further configured to, when a second matching relationship is obtained, send the first Rx interface request message to an adjacent LDRA corresponding to the second matching relationship, so that the adjacent LDAR performs session binding, and transmit a corresponding Rx interface request message to the corresponding PCRF.

In other words, the function of the LDRA is performed by the neighboring LDRA.

The first sending unit 85 is further configured to send the first Rx interface request message to the HDRA when the second matching relationship is not obtained, so that the HDRA sends the first Rx interface request message to the second LDRA.

In practical applications, the first receiving unit 81 and the first sending unit 85 may be implemented by a transceiver in the LDRA; the first matching Unit 82, the first session binding Unit 83, the filling Unit 84, the recording Unit, and the second matching Unit may be implemented by a Central Processing Unit (CPU), a Microprocessor (MCU), a Digital Signal Processor (DSP), or a Programmable logic Array (FPGA) in the LDRA.

To implement the method of the embodiment of the present invention, the embodiment further provides an HDRA, as shown in fig. 9, where the HDRA includes: a second receiving unit 91 and a second transmitting unit 92; wherein the content of the first and second substances,

the second receiving unit 91 is configured to receive a first Rx interface request message sent by a first LDRA;

the second sending unit 92 is configured to send the first Rx interface request message to a corresponding second LDRA according to the user public network IP address carried in the first Rx interface request message, so that the second LDRA performs session binding, and transmits the corresponding Rx interface request message to a corresponding PCRF, or send the first Rx interface request message to a corresponding second HDRA, so that the second HDRA allocates the corresponding LDRA or HDRA to the first Rx interface request message.

In an embodiment, the HDRA may further include: a third matching unit, configured to match a locally configured third correspondence table with the user public network IP address carried in the first Rx interface request message, to obtain a third matching relationship; the third corresponding relation table is the corresponding relation between the user public network IP address and the LDRA;

correspondingly, the second sending unit 92 is configured to send the first Rx interface request message to the second LDRA according to the third matching relationship.

In an embodiment, the HDRA may further include: a fourth matching unit, configured to match a locally configured fourth correspondence table with the user public network IP address carried in the first Rx interface request message, to obtain a fourth matching relationship; the fourth corresponding relation table is the corresponding relation between the IP address of the user public network and the HDRA;

accordingly, the second sending unit 92 is configured to send the first Rx interface request message to the second HDRA according to the fourth matching relationship.

In practical application, because the HDRA further has a routing function, after receiving the first Rx interface request message, first of all, it is queried whether the first Rx interface request message carries a destination PCRF identifier (for example, Dest-host), and when the first Rx interface request message carries the destination PCRF identifier, the first Rx interface request message is routed according to the destination PCRF until the first Rx interface request message is transmitted to the destination PCRF.

Here, the specific operation process of the second LDRA is completely the same as the function of the above LDRA, and is not described herein again.

The specific processing procedure of the second HDRA is completely the same as the HDRA function described above, and is not described again.

In practical applications, the second receiving unit 91 and the second sending unit 92 may be implemented by transceivers in the HDRA; the third matching unit and the fourth matching unit can be realized by a CPU, an MCU, a DSP or an FPGA in the HDRA.

In order to implement the method according to the embodiment of the present invention, this embodiment further provides a PCRF, as shown in fig. 10, where the PCRF includes: a third receiving unit 101 and a second session binding unit 102; wherein the content of the first and second substances,

the third receiving unit 101 is configured to receive a second Rx interface request message;

the second session binding unit 102 is configured to perform session binding according to the PCEF identifier in the second Rx interface request message and the user private network IP address information.

In practical application, when the second Rx interface request message corresponds to an Rx interface new call, the second session binding unit 102 may perform session binding according to a PCEF identifier in the second Rx interface request message and user private network IP address information, and when the second Rx interface request message corresponds to a non-Rx interface new call, the second session binding unit 102 may perform session binding according to a session ID in the second Rx interface request message, where a specific processing procedure may refer to the prior art.

The PCRF may further include: a policy decision unit; wherein the content of the first and second substances,

the second session binding unit 102 is further configured to trigger the policy decision unit after session binding;

In practical application, the third receiving unit 101 may be implemented by a transceiver in the PCRF; the second session binding unit 102 and the policy decision unit may be implemented by a CPU, an MCU, a DSP, or an FPGA in the PCRF.

It should be noted that, as used herein, the first and second … … only indicate different messages, LDRA or HDRA, and do not limit the functions of the messages, LDRA or HDRA.

In the session binding scheme provided in this embodiment, the first receiving unit 81 of the LDRA receives the first Rx interface request message; when it is determined that the first Rx interface request message does not carry the destination PCRF identifier, the first matching unit 82 of the LDRA matches the locally configured first mapping table, locally stored Gx interface session information, and the user public network IP address information carried in the first Rx interface request message; the first corresponding relation table is a corresponding relation table of the user public network IP address and the PCEF in the first LDRA tandem area; when the first matching relationship is obtained, the first session binding unit 83 of the LDRA performs session binding; filling the PCEF identification corresponding to the first matching relationship and the corresponding PCRF identification in the first Rx interface request message to obtain a second Rx interface request message; the corresponding PCEF identifier is used for session binding of the corresponding PCRF; a filling unit 84 of the LDRA routes the second Rx interface request message according to the corresponding PCRF identifier; the third receiving unit 101 of the corresponding PCRF receives the second Rx interface request message, the second session binding unit 102 of the corresponding PCRF performs session binding according to the PCEF identifier in the second Rx interface request message and the user private network IP address information, and the LDRA only performs pairing of the corresponding relationship between the user public network IP address and the PCEF in the local tandem area, so that the processing overhead of the LDRA can be greatly reduced. Meanwhile, the user association, namely the session binding, can be realized under the condition that the IP address of the user private network is repeated.

In addition, the second receiving unit 91 of the HDRA receives the first Rx interface request message sent by the first LDRA; the second sending unit 92 of the HDRA sends the first Rx interface request message to the corresponding second LDRA according to the user public network IP address carried in the first Rx interface request message, so that the second LDRA performs session binding, and transmits the corresponding Rx interface request message to the corresponding PCRF, or sends the first Rx interface request message to the corresponding second HDRA, so that the second HDRA allocates the corresponding LDRA or HDRA to the first Rx interface request message, and the HDRA does not need to record session binding information, thereby greatly reducing the overhead of the HDRA and reducing the modification difficulty.

In addition, the third matching unit of the HDRA matches a locally configured third correspondence table with the user public network IP address carried in the first Rx interface request message to obtain a third matching relationship; the third corresponding relation table is the corresponding relation between the user public network IP address and the LDRA; the second sending unit 92 sends the first Rx interface request message to the second LDRA according to the third matching relationship; or, the fourth matching unit of the HDRA matches a locally configured fourth correspondence table with the user public network IP address carried in the first Rx interface request message to obtain a fourth matching relationship; the fourth corresponding relation table is the corresponding relation between the IP address of the user public network and the HDRA; the second sending unit 92 sends the first Rx interface request message to the second HDRA according to the fourth matching relationship, and the HDRA only performs pairing of the corresponding relationship between the user public network IP address and the LDRA or pairing between the user public network IP address and the HDRA, so that the processing overhead of the HDRA can be greatly reduced, and the transformation difficulty is further reduced.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of a hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention.

Claims

1. A session binding method applied to a first visited routing agent LDRA, the method comprising:

receiving a first Rx interface request message;

when the first Rx interface request message is determined not to carry the target policy control and charging rule function entity PCRF identification, matching a first corresponding relation table configured locally, Gx interface session information stored locally and user public network IP address information carried in the first Rx interface request message; the first corresponding relation table is a corresponding relation table of the user public network IP address and the policy control and charging execution function entity PCEF in the first LDRA tandem area;

when the first matching relation is obtained, session binding is carried out;

2. The method of claim 1, further comprising:

3. The method of claim 2, wherein the performing session binding is:

4. The method according to any one of claims 1 to 3, further comprising:

5. The method of claim 4, further comprising:

and when the second matching relation is not obtained, the first Rx interface request message is sent to a home routing agent (HDRA), so that the HDRA sends the first Rx interface request message to a second LDRA.

6. A session binding method applied to a first HDRA, the method comprising:

receiving a first Rx interface request message sent by a first LDRA;

7. The method as claimed in claim 6, wherein the sending the first Rx interface request message to the corresponding second LDRA according to the user public network IP address carried in the first Rx interface request message is:

8. The method according to claim 6, wherein the sending the first Rx interface request message to the corresponding second HDRA according to the user public network IP address carried in the first Rx interface request message is:

9. A session binding method is applied to PCRF, and the method comprises the following steps:

receiving a second Rx interface request message;

according to the PCEF identification in the second Rx interface request message and the IP address information of the user private network, carrying out session binding; wherein the content of the first and second substances,

the received second Rx interface request message is obtained by filling the PCEF identifier and the PCRF identifier in the first Rx interface request message received by the first LDRA, and is routed according to the PCRF identifier;

the PCEF identifier and the PCRF identifier are the PCEF identifier corresponding to the first matching relationship and the PCRF identifier corresponding to the first matching relationship;

the first matching relationship is obtained by matching a first corresponding relationship table configured locally, locally stored Gx interface session information and user public network IP address information carried in the first Rx interface request message when the first LDRA determines that the first Rx interface request message does not carry a destination PCRF identifier; the first corresponding relation table is a corresponding relation table of the user public network IP address and the PCEF in the first LDRA convergence area.

10. The method of claim 9, further comprising:

and triggering corresponding policy decision after the session is bound.

11. An LDRA, comprising: the device comprises a first receiving unit, a first matching unit, a first session binding unit, a filling unit and a first sending unit; wherein the content of the first and second substances,

12. The LDRA of claim 11, wherein the LDRA further comprises: and the recording unit is used for recording the PCRF identification, the PCEF identification and the private network IP address information corresponding to the user when the user is activated to form Gx interface session information.

13. The LDRA according to claim 11 or 12, wherein the LDRA further comprises: a second matching unit, configured to match the first correspondence table, locally stored Gx interface session information, and user IP address information carried in the first Rx interface request message, and perform matching according to a locally configured second correspondence table when the first matching relationship is not obtained; the second corresponding relation table is a corresponding relation table of the user public network IP address in the adjacent tandem area of the LDRA and the adjacent direct-connected LDRA;

14. The LDRA of claim 13, wherein the first sending unit is further configured to send the first Rx interface request message to the HDRA when the second matching relationship is not obtained, so that the HDRA sends the first Rx interface request message to the second LDRA.

15. An HDRA, comprising: a second receiving unit and a second transmitting unit; wherein the content of the first and second substances,

16. The HDRA of claim 15, further comprising: a third matching unit, configured to match a locally configured third correspondence table with the user public network IP address carried in the first Rx interface request message, to obtain a third matching relationship; the third corresponding relation table is the corresponding relation between the user public network IP address and the LDRA;

17. The HDRA of claim 15, further comprising: a fourth matching unit, configured to match a locally configured fourth correspondence table with the user public network IP address carried in the first Rx interface request message, to obtain a fourth matching relationship; the fourth corresponding relation table is the corresponding relation between the IP address of the user public network and the HDRA;

18. A PCRF comprising: a third receiving unit and a second session binding unit; wherein the content of the first and second substances,

the second session binding unit is used for carrying out session binding according to the PCEF identifier in the second Rx interface request message and the IP address information of the private network of the user; wherein the content of the first and second substances,

19. The PCRF of claim 18, further comprising: a policy decision unit; wherein the content of the first and second substances,

20. A storage medium storing a computer program, characterized in that the computer program realizes the steps of the method of any one of claims 1 to 10 when executed by a processor.