KR20030083519A - Service method for Packet Data of GPRS Network - Google Patents

Abstract

PURPOSE: A method for giving a packet data service in a GPRS network is provided to supply receiving subscriber information to a DNS server, and to request session establishment as a prescribed port number, thereby easily transmitting packet data to an internal network from an external network. CONSTITUTION: The first host(310) requests the first subscriber information to a DNS server(320)(S301). The DNS server(320) provides the first subscriber information to the first host(310)(S302). The first host(310) transmits a session established request to a GGSN(331)(S303). The GGSN(331) performs a network initialization PDP context procedure with an IMSI(International Mobile Subscriber Identity) value(S304). If a GTP session is established, the GGSN(331) transmits a session established response message to an IP address of the first host(310)(S305). The first host(310) recognizes a session establishment, and transmits traffic data to an IP address of the second host(S306).

Description

Packet data service method in JPRS network {Service method for Packet Data of GPRS Network}

The present invention relates to a packet data service method for a GPRS network, in particular, a GPRS external network to a GPRS internal network.

UMTS (Universal Mobile Telecommunication System), a third generation mobile communication system standardized in 3GPP, defines a general packet radio service (GPRS) system to provide packet data services such as the Internet. The GRPS system has its own IP-based backbone network for communication between a Serving GPRS Support Node (SGSN) and a Gateway GPRS Support Node (GGSN) that perform packet switch functions. In addition, GPRS system provides roaming service for subscribers of ISP network for interworking with ISP (Internet Service Provider) network, and mobile IP system for providing mobile IP service is also defined.

GPRS was originally designed for Global System for Mobile Communications (GSM), but was also adopted in IS-136. GPRS is a new bearer service for GSM and can simplify wireless access to packet data networks and improve performance. As a result, GPRS increases radio resource usage efficiency and provides advantages such as high data rate and short connection setup time. GPRS also simplifies access to packet data networks.

GPRS has been standardized by the European Telecommunications Standards Institute (ETSI) in recent years. In addition, testing is underway in a production environment, and GPRS is expected to be commercialized in many regions in mid-2000.

Meanwhile, to integrate GPRS into the existing GSM architecture, a new network component called GPRS Support Node (GSN) has been introduced. The GSN is responsible for transferring and routing data between the mobile terminal and a packet data network (PDN). A GPRS system will be described in detail with reference to FIG. 1.

1 is a block diagram showing a logical structure of a conventional GPRS system. Referring to FIG. 1, a GPRS system has newly defined services, interfaces, and system specifications to provide 3G service capability, and is an evolution of an interface and system defined in a 2G GSM core network.

Therefore, the GPRS system supports mutual roaming service and handover with 2G GSM network.

The Mobile-service Switching Center (MSC) 101 is responsible for mobility management and voice call processing for circuit mode service subscribers, and the VLR (Visited Location Register) 102 provides all information about mobile terminals in the area it manages. Is a database that temporarily stores the data related to the Home Location Register (HLR) 103, and always remains the same.

The MSC 101 and VLR 102 may be extended in functionality for effective cooperation between the existing GSM circuit switched service and packet switched service using GPRS. For example, location information updating can be combined into one, and the attach procedure can be integrated and operated in the same way.

The HLR 103 is a database that stores and manages subscriber parameters and location information for all mobile terminals registered in its home network (eg, IMT-2000). Accordingly, the HLR 103 stores a user profile, a current SGSN IP, a PDP IP, and the like for each GPRS user included in a PLMN. The Gr interface is then used to exchange this information between the HLR and SGSN.

For example, SGSN informs HLR of the current location of the mobile terminal. When the mobile terminal registers with the new SGSN, the HLR informs the SGSN of the mobile terminal information. On the other hand, the signaling path between GGSN and HLR (defined as Gc interface) is used when GGSN wants to obtain the current location and profile information of the user.

The Serving GPRS Support Node (SGSN) 104 is a serving node of a general packet radio service (GPRS) that is responsible for delivering packets to or from a mobile station in a management area. It is responsible for packet mode data service management of a mobile terminal by setting a mobile management context. That is, functions performed by the SGSN 104 include packet routing and forwarding, attach, detach, location management, logical link management, and authentication and charging.

The SGSN 104 establishes a PDP context with the GGSN 105 and delivers a service data unit (SDU) using GPRS Tunneling Protocol (GTP) tunneling. In other words, in the GPRS network, GTP, a new tunneling protocol, is introduced between SGSN and GGSN to support mobility processing, registration, and authentication of packet terminals.

The Gateway GPRS Support Node (GGSN) 105 is a GPRS gateway node located between a GPRS backbone network and an external packet data network (PDN) and directly connected to a PDN or the Internet. GPRS has tunneling and Internet Protocol (IP) routing functions by maintaining routing information to SGSN 104. In this case, the routing information is used to tunnel a service data unit (SDU) to the SGSN 104 supporting the packet mode data service of the current mobile station. Therefore, the packet transmitted from the SGSN is converted into an appropriate Packet Data Protocol (PDP) format through the GGSN and sent to the counterpart PDN. On the contrary, the packet transmitted from the external PDN goes through the reverse process. At this point, GPRS is primarily responsible for the translation between a valid PDP IP in an external PDN and a valid address in a GSM network.

In order to deliver a packet received from an external PDN to a mobile station, the GPRS system needs to know the SGSN currently managing the mobile station. Therefore, the database (PDP context) held by the GGSN stores the user's current SGSN information together with the user profile.

In addition, the main functions of the GGSN 105 include IP address assignment and management, mobile point-to-point protocol (PPP) generation, termination and relay, for connection services with ISPs or other Internet Service Providers (ISPs). Screening function.

In general, many-to-many relationships are established between SGSN and GGSN. One GGSN may be used as an interface point between multiple SGSNs and one PDN. In contrast, one SGSN may use multiple GGSNs to send packets to different PDNs.

A mobile station (MS) may be composed of a mobile terminal (MT) serving as an IMT-2000 wireless modem and a terminal equipment (107) supporting application services. It is standardized for compatibility with Universal Service Identification Module (USIM) cards.

Mobile terminal types are generally classified into three modes.

Mode I is a terminal type capable of both line mode and packet mode services, Mode II is a terminal type capable of providing both line mode and packet mode services but not simultaneously, and Mode III is only a line mode or packet mode service. It is a terminal type that can be provided.

Equipment Identity Register (EIR) 108 is a database that manages mobile station ID management.

Additional devices in the IMT-2000 core network include Gateway Location Register (GLR) to support roaming services with other PLMNs (109), SMSC (SMS Center, 110) for SMS, and SCP (Service Control Point) for intelligent network services. ) And Gateway Mobile Location Center (GMLC) to provide Location Based Services (LCS).

The GPRS network interworks with a PDN (public data network) or the Internet. At this time, the GGSN performs a router function in terms of interworking with the Internet and Gi matching. The GPRS subsystem includes a domain name system (DNS) server and Dynamic Host Configuration Protocol (DHCP) processing. In other words, as defined in the 3GPP specification, an ISP performs an authentication process and an IP allocation process in an ISP for an ISP subscriber and opens a bearer for packet transmission even if the subscriber is not a GPRS network through a Gi interface. .

GGSN manages a database called PDP context, which can provide packet service to GPRS external network. Therefore, in order to provide packet service to the GPRS external network, the PDP context should always be activated first by the terminal of the GPRS internal network.

Accordingly, the GPRS subscriber can receive packet data and wireless Internet service through the GPRS packet data network. GPRS network supports external mobile IP subscribers or ISP subscribers who have moved to GPRS network to access their home network through GPRS network and receive wireless packet data and Internet service as in home.

In general, in a situation where the PDP context is not activated, when packet data without subscriber information arrives from a GPRS external network with a terminal that does not exist in the PDP context, the GGSN discards the received packet data.

However, even in this case, in a special case in which the subscriber information is previously defined in the GGSN, the PDP context activation process may be performed through the procedure as shown in FIG.

2 is a flowchart illustrating an operation process when a transmitting terminal located in a conventional GPRS external network transmits packet data to an internal network in which subscriber information of a receiving terminal is registered.

First, when the subscriber information is registered in the receiving terminal, the GGSN receives packet data including the IP and data of the receiving terminal from the transmitting terminal located in the GPRS external network (S201).

The GGSN sends a routing information request message for GPRS to the HLR using the IP of the receiving terminal to know the SGSN to which the current receiving terminal belongs (S202), and the HLR routes the GPRS including the SGSN IP in response thereto. The information response message is transmitted to the GGSN (S203).

The GGSN, which has received the SGSN IP from the HLR, requests the SGSN to proceed with the PDP context activation process using the PDU (Protocol Data Unit) notification request message (S204).

Then, SGSN transmits a response message to the request to GGSN (S205).

If the receiving terminal is registered in the mobility management (MM) context in the SGSN, the SGSN requests the receiving terminal to activate the PDP context using the PDP context activation request message (S206).

Accordingly, the receiving terminal proceeds to activate the PDP context (S207).

However, the above process is limited to a special case in which subscriber information of a receiving terminal is registered in the GGSN.

In this case, in general, when information (ie, subscriber information) about a receiving terminal to which packet data is to be transmitted is not registered in the PDP context because the PDP context is not activated, when packet data is received from a transmitting terminal of a GPRS external network, Since the information on the receiving terminal cannot be found, the received packet data is discarded because it is not transmitted to the GPRS internal network receiving terminal (discard), and thus there is a problem in that the packet data is not transmitted between the transmitting and receiving terminals.

The present invention has been made to solve the above problems, to provide the subscriber information including the GGSN IP and IMSI of the other terminal through the DSN server for the terminal to access from the GRPS external network to the internal network It is characterized by that.

Another object of the present invention is characterized in that the terminal of the GRPS external network requests the session using the subscriber information and the port number of the counterpart when requesting the session to the GRPS network, and thus can perform the PDP context.

Still another object of the present invention is to include a TCP port number or a UDP port number in a session request message and transmit the same to a GGSN of a GRPS network.

According to the present invention, in order to prevent discarding a packet to be transmitted because the PDP context is not activated in the GRPS external network, traffic data can be transmitted between transmitting and receiving terminals after activating the PDP context using the subscriber information and the port number. It is in such a way.

1 is a logical structure of a GPRS network.

2 is a flowchart illustrating an operation process when a packet data is transmitted from a conventional GPRS external network to an internal network to which subscriber information is registered.

3 is a flowchart illustrating a method of serving a mobile packet data to a GPRS internal network by a host located in a GPRS external network according to an exemplary embodiment of the present invention.

4 is a diagram illustrating a session establishment protocol between a GGSN of a GPRS network and a host of an external network according to an exemplary embodiment of the present invention.

Packet data service method in a GPRS network according to the present invention for achieving the above object,

Requesting first subscriber information including the IP of the GGSN of the GPRS internal network and subscriber identification information (IMSI) from a first host located in a GPRS external network to a DNS server, and receiving the first subscriber information;

Transmitting the subscriber information and the TCP port number to a GGSN of a GPRS internal network at the first host;

Confirming the first subscriber information and the port number received by the GGSN, and then activating a PDP context on a second host of a GPRS internal network;

And when the first host receives the second subscriber information for the second host from the GGSN of the GPRS internal network, transmitting the packet data.

Preferably, the first subscriber information includes an IP address and subscriber identification information of a GGSN located in an internal network of GPRS.

Preferably, the port number is a TCP port number predetermined by the GGSN and the first host of the GPRS internal network.

Preferably, the port number is assigned to a port number existing in the TCP or UDP layer.

Preferably, the GGSN recognizes whether the PDP context is activated according to the result of confirming the subscriber information and the port number.

Preferably, the port number transmitted from the first host to the GGSN of the GPRS network is a session establishment request message.

Preferably, the session establishment in the GGSN is established when both the first condition that the packet is received and the second condition that the TCP port number must be a previously promised number are established using the IP address of the GGSN itself. .

Preferably, the PDP context activation step may include: requesting activation of the PDP context from the corresponding second host by using a second host IP address corresponding to the subscriber identification information in a GGSN; A second host activating a PDP context; And GGSN providing the IP address of the second host to the first host.

Packet data service method in a GPRS network according to another embodiment of the present invention, the first host located in the GPRS external network requests the first subscriber information including the GGSN IP and subscriber identification information for the GPRS internal network to the DNS server Receiving first subscriber information of the GRPS internal network; Requesting, by the first host, to establish a session with a GGSN of a GPRS internal network using the first subscriber information and the TCP port number; Confirming the first subscriber information and the port number received by the GGSN, and establishing a session by activating a PDP context for a second host of a GPRS internal network; And informing the second host of establishing a session, and then transmitting traffic data between the first host of the GPRS external network and the second host of the GPRSN internal network.

In the present invention, in order to prevent a packet received from an externally located terminal or host is discarded because the PDP context is not activated in the GRPS network, the sender uses counterpart subscriber information and port number. By activating the PDP context of the GRPS network, it is possible to transmit traffic data between the transmitting and receiving terminal or the host.

A packet data service method in a GPRS network according to an exemplary embodiment of the present invention as described above will be described with reference to the accompanying drawings.

3 is a block diagram schematically illustrating a connection relationship between a GPRS internal network and a host of an external network in a GPRS system according to the present invention.

Referring to FIG. 3, the GPRS system includes a first host (Host1) 310, a DNS server (DNS Server) 320, a GGSN 331 and SGSN 332 of a GPRS network 330, and a GPRS external network. And a second host (Host 2) 333 of the GPRS internal network.

The first host 310 is a host or mobile station located in a GPRS external network. The first host 310 is configured to provide first subscriber information including GGSN IP and subscriber identification information of the GPRS internal network using a host identification information. 320, the DSN server 320 provides the first host 310 with first subscriber information including the GGSN IP and the subscriber identification information (IMSI) of the GPRS internal network in response to the request. (S302).

In this case, the DNS server 320 may interwork the HLR according to the request of the first host 310 and provide subscriber information provided from the HLR to the first host 310. Here, the Domain Name System (DNS) refers to a system used in the Internet to convert a name of a network node into an address. As described above, the HLR is a database that stores and manages subscriber parameters and location information for all mobile terminals registered in its network.

In this way, the first subscriber information requested by the first host 310 to the DNS server 320 includes the GGSN IP of the GPRS network and the other party's subscriber identification information (IMSI).

Here, the subscriber identity information (IMSI: International Mobile Subscriber Identity) is a number assigned by the system when a subscriber first subscribes, and includes a PLMN code and an HLR code, in addition to a country code, and a SIM (Subscriber Identity Module) card. It is stored in the Authentication Center (AuC).

Then, the first host 310 transmits a session establishment request message to the GGSN 331 of the GPRS network 330 using the subscriber information (S303).

In this case, the message for requesting session establishment by the first host 310 to the GGSN 331 of the GPRS network includes a GGSN IP, a TCP port number, and subscriber identification information (IMSI), which are destination addresses. That is, the IP datagram transmitted from the first host shown in FIG. 4A to the GGSN of the GRPS network includes the GGSN IP in the IP header, the port number in the TCP header, and the other party's subscriber identification information in the IMSI.

In this case, the IP datagram is preferably encapsulated using a GGSN IP as a header. Therefore, even if the subscriber information is not registered in the GGSN 331, the first host requests the information of the GGSN from the DNS server 320, encapsulates the subscriber information provided with the other subscriber information, and then provides the GGSN. By sending to 331, a session establishment is requested.

When the GGSN 331 receives the session establishment request message from the first host 310, as shown in (a) of FIG. 4, the GGSN 331 is assigned by the GGSN IP in the IP header layer 412 of the IP datagram. Determine that the IP address is the destination address. The packet is then forwarded to the upper TCP layer 413. The TCP layer 413 looks at the port number and forwards the packet to the application 414. At this time, the GGSN recognizes that the network PDP context procedure should be performed.

Here, the application 414 in the protocol plane of the GGSN means software running in the GGSN system, and the socket is opened to the corresponding TCP port. If you do not open a socket on the TCP port, the TCP layer sends an Internet Control Message Protocol (ICMP) message back to the first host to inform you of the error.

In addition, the GGSN 331 recognizes that the IP datagram is delivered to itself through the reception of an IP datagram including its own IP information, and decapsulates the IP datagram without discarding the subscriber identification information. Extract Based on the subscriber identification information, the GGSN 331 requests routing information from the HLR, and receives an IP of the SGSN 332 in response thereto. That is, the GGSN 331 may be provided with an SGSN IP that must pass to transmit packet data to the second host 333 using the subscriber identification information.

In addition, the GGSN 331 performs a network initialization PDP context procedure defined in 3GPP 26.060 as a subscriber identity (IMSI) value (S304). This network initialization PDP context procedure activates the second host 333. The GGSN requests the second host to activate the PDP context using the IP address of the second host 333 corresponding to the subscriber identification information. Activates.

At this time, in order to open a session normally, a packet is received using the IP of the GGSN as a destination, and a TCP port number is promised as a predetermined port number between two systems (Host 1-GGSN) in advance. That is, two conditions must be satisfied.

Then, when the GGSN 331 establishes the GTP session, the GGSN 331 transmits a response message to the first host 310 to inform that the session is normally established. In this case, the session establishment response message as shown in (b) of FIG. 4 is transmitted using the IP address of the first host located in the GPRS external network as the destination address (S305).

Here, the session establishment response message includes the second subscriber information, and the second subscriber information includes the IP address of the second host, the TCP header, and the IP address information of the first host, which is a destination address.

After receiving the session establishment response message, the first host 310 recognizes the establishment of the session and transmits traffic data to the IP address of the second host included in the response message (S306).

As described above, when receiving the first subscriber information located in the internal network from the first host 310 located in the GPRS external network, the GGSN 331 of the GPRS network recognizes that the PDP context should be activated. The method for recognizing PDP context activation in GGSN will be described in detail as follows.

If you want to send an IP datagram from the first host 310 located in the GPRS external network to the second host 333 in the internal network, you can add the TCP port number to the IP datagram in addition to the GGSN IP address and IMSI as the first subscriber information. Include it and send it.

To this end, the IP datagram includes a TCP header area that may include a GGSN IP address, an IMSI, and a TCP port number, as shown in (a) of FIG. 4.

Therefore, the first subscriber information includes the GGSN IP information, the receiving subscriber identification information (IMSI), and the second subscriber information includes the IP address for the second host and the IP address for the first host.

The TCP port number may be predefined between the first host and the GGSN. The TCP port number is a number assigned to a port assigned to the TCP layer in the GGSN hierarchy. The TCP port number is assigned to a specific port among the ports assigned to the TCP layer. Is a number defined between the first host and the GGSN so that activation of the PDP context is initiated through it. In some cases, of course, instead of the TCP port, a specific UDP port among the UDP ports existing in the UDP layer may be numbered to activate the PDP context.

When the GGSN receives the IP datagram from the first host of the GPRS external network, the GGSN examines the IP header area of the IP datagram in the IP layer to determine whether the GGSN is its own IP address.

As a result of the checking, when the IP address of the GGSN is its own, the IP layer forwards the IP datagram to the TCP layer, and when the IP datagram is forwarded, the TCP layer checks the TCP header area and checks the TCP port number.

If the result of the check is a predefined port number between the GGSN and the first host, the TCP layer forwards the IP datagram to the corresponding application through the TCP port corresponding to the port number. The application extracts IMSI from the forwarded IP datagram.

Thus, the GGSN establishes a session using the extracted IMSI to activate a PDP context between the second host and the GGSN to transmit packet data from the first host to the second host.

As described above, since the terminal of the GPRS external network can transmit the packet data to the receiving terminal whose subscriber information is not registered in the PDP context on the GPRS system, data transmission between the GPRS external network and the internal network can be easily performed.

As described above, in the present invention, the IP datagram transmitted by the first host to the GGSN of the GRPS internal network may include the GGSN's IP, subscriber identification information (IMSI), and TCP header information, or the IP datagram may be included in the IP datagram. A data area may be added and transmitted.

As described above, according to the packet data service method in the GPRS network according to the present invention, after providing the subscriber side subscriber information to the DNS server for the terminal requesting access to the internal network through the GPRS external network, By requesting session establishment as a promised port number, it is possible to easily transmit packet data from GPRS external network to internal network and to effectively provide roaming service.

Claims (11)

Requesting first subscriber information including a GGSN IP address and IMSI of a GPRS internal network to a DNS server from a first host located in a GPRS external network, and receiving the first subscriber information; Transmitting, at the first host, the first subscriber information and the TCP port number to a GGSN of a GPRS internal network; Confirming the first subscriber information and the port number received by the GGSN, and then activating a PDP context on a second host of a GPRS internal network; And transmitting the packet data with the second host when the first host receives the second subscriber information from the GGSN of the GPRS internal network. The method of claim 1, The first subscriber information includes an IP address of a GGSN located in a GPRS internal network and a subscriber identity information (IMSI) of a packet data service in a GPRS network. The method of claim 1, The port number is a packet data service method in a GPRS network, characterized in that the TCP port number predetermined by the GGSN and the first host of the GPRS internal network. The method of claim 1, And the port number is assigned to a port number existing in a TCP or UDP layer. The method of claim 1, The GGSN of the GPRS network is a packet data service method of the GPRS network, characterized in that whether the GGSN activates the PDP context according to the first subscriber information and port number received from the first host. The method of claim 1, The port number transmitted from the first host to the GGSN of the GPRS network is a session establishment request message. The method according to claim 1 or 6, In the GPRS network, the session establishment in the GGSN is established when both the first condition that the packet is received and the second condition that the TCP port number must be a previously promised number are satisfied by using the IP address of the GGSN itself. Packet data service method. The method of claim 1, In the performing of the PDP context activation, Requesting activation of the PDP context from the GGSN by using the IP address of the second host corresponding to the subscriber identification information; A second host activating a PDP context; And GGSN providing an IP address for a second host to the first host. Requesting subscriber information of a GPRS internal network from a first host located in a GPRS external network to a DNS server, and receiving the subscriber information; Requesting to establish a session with a GGSN of a GPRS internal network using the subscriber information and the TCP port number at the first host; Confirming the received subscriber information and the port number by the GGSN, and establishing a session by activating a PDP context for a second host of a GPRS internal network; And transmitting the traffic data between the first host of the GPRS external network and the second host of the GPRSN internal network after notifying the first host of the establishment of a session. The method of claim 9, The IP datagram transmitted by the first host to the GGSN of the GPRS internal network includes the IP address of the GSN, the TCP port number, and the subscriber identification information (IMSI). The method of claim 9, The IP datagram transmitted by the first host to the GGSN of the GPRS internal network includes the IP address, the TCP port number, the subscriber identification information (IMSI), and the data area of the GGSN. .