KR101001472B1 - Softswitch with Multi-Transport Protocol Processing - Google Patents

Abstract

In the present invention, a soft switch constituting Next Generation Network (hereinafter, NGN: Next Generation Network) accommodates both User Datagram Protocol (UDP), Transmission Control Protocol (TCP), and StreamControl Transmission Protocol (SCTP) as a transport protocol. It's about technology that makes it possible.

To this end, the present invention manages a socket session for processing a TCP message in the TCP layer, while the UDP layer, the TCP layer, and the SCTP layer are mounted on an IP layer, and processes the SCTP message in the SCTP layer. ACS which manages a socket session to maintain a session for transmission of the TCP message and the SCTP message, and performs a call distribution NAT function on the transport layer (UDP layer, TCP layer, and SCTP layer). Internal messages are used between UCP-I / Ps that perform resource management for call processing.

Description

Softswitch having multi transport protocol process function

1 is a block diagram of a general NGN.

Figure 2 is a detailed block diagram of a soft switch with a multi-transport protocol processing function according to an embodiment of the present invention.

3 is a signal flow diagram illustrating a UDP message processing procedure in a soft switch according to an embodiment of the present invention.

4 is a signal flow diagram illustrating a TCP message processing procedure in a soft switch according to an embodiment of the present invention.

5 is a signal flow diagram illustrating an SCTP message processing procedure in a soft switch according to an embodiment of the present invention.

The present invention relates to a soft switch having a multi-transport protocol processing function. More specifically, a soft switch constituting a next generation network (hereinafter referred to as NGN) is a transport protocol (UDP) as a user datagram protocol. It relates to a technology that can accommodate both Transmission Control Protocol (TCP) and StreamControl Transmission Protocol (SCTP).

NGN simplifies the structure of different networks (PSTN, ATM, IR, FR, dedicated network, wireless network, etc.) into one common packet-based network to reduce network construction costs, operation costs, and provide a flexible network solution. It also refers to a network that adopts an open exchange technology that defines a data integrated multimedia communication network in MSC, ISC, etc.

Since NGN is an Open Achitecture, it is possible to supply vendor independent facilities, develop and provide services through Open API, and to ensure independence in delivery layer technology. Can be. In addition, since NGN is a single transport network, it can provide multiservices such as voice / data / video communication, integrate various wired / wireless broadband media, unify operation management and maintenance systems, and The overlay network can be implemented as an integrated high speed packet network. In addition, NGN provides a Network Indepent Service, which can provide time to market services, provide independent services to suppliers through the Open API, and quickly introduce various types of services. It provides network flexibility by guaranteeing quality of service (QoS) / cost of service (CoS) for each service.

Referring to Fig. 1, the NGN configuration will be schematically described.

NGN is an access gateway 10 for accepting a variety of subscriber services, such as a general telephone, xDSL, leased line, all in a single system centered on the soft switch (20); A trunk gateway 20 configured to perform STM or trunk interfacing between the PSTN and the packet network, establish a local connection with the soft switch 20, and establish / manage transport connections through the packet network under the control of the soft switch 20; And an application server (not shown) that performs a function of providing an environment in which applications and additional services can be generated and executed.

As shown in FIG. 1, the access gateway 10 accommodates the POT terminal 2 and the PC terminal 4 via the modem 6, and also directly accepts the general POTS terminal 8, which includes a modem 6. Subscriber traffic transmitted through the soft switch 20 is transmitted, and the subscriber signal transmitted from the POTS terminal 8 is transmitted to the Public Switched Telephone Network (PSTN).

Between the access gateway and the soft switch 20, the router for performing the routing function for the IP packet based on the destination address and the NAS 12 to authenticate the subscriber to the router to deliver the IP packet to the soft switch 20 (14) is located.

Meanwhile, the SIP terminal 18 is connected to the soft switch 20. The SIP terminal 18 is a terminal that performs a voice call through a packet network after performing a call connection using a SIP message.

The access gateway 10, the trunk gateway 30, and the soft switch 40, which are external devices that may be connected to the soft switch 20, may transmit the protocol of the transport layer, which is the OSI 4 layer, to one of UDP, TCP, or SCTP. Adopt.

Therefore, in order not to be restricted by the compatibility with external devices, it should be able to handle all the transport protocols that external devices may have, namely, UDP / TCP / SCTP.

An object of the present invention is to provide a soft switch capable of handling all of various transport protocols (UDP / TCP / SCTP).

In order to achieve the above object, a soft switch having a multi-transport protocol processing function according to a preferred embodiment of the present invention comprises: a TCP layer configured on an IP layer to process a TCP message transmitted from an external device; A UDP layer configured above the IP layer to process a UDP message transmitted from the external device; An SCTP layer configured above the IP layer to process an SCTP message transmitted from the external device; A TCP session manager configured on the TCP layer to perform socket management for TCP message transmission; An SCTP session manager configured on the SCTP layer to perform socket management for SCTP message transmission; An ACS for processing a UDP message received from the UDP layer, a TCP message received from the TCP layer, and an SCTP message received from the SCTP layer into a UPD message and transmitting the same to a UCP-I / P; And a UCP-I / P that analyzes the UPD message and manages resources for a predetermined call processing requested from the external device based on the analysis result.

First, UDP, TCP, and SCTP corresponding to a transport protocol will be described.                     

The UDP is a very simple but unreliable transport layer protocol, and the UDP header has a source IP and a destination IP, which allow higher protocols to distribute messages to specific applications.

TCP is Reliability Guarantee A transport layer protocol that provides transport and virtual connection services, which ensures reliability in data transmission through a packet retransmission function using a sequence number when necessary.

SCTP is a transport layer protocol corresponding to UDP and TCP. Although it can be compared with TCP in that it is very reliable, it is functionally independent of performance in that it has various functions that TCP does not have. Is better. The purpose of SCTP is to transmit PSTN signaling information in an IP network, and can be used for various application services that can effectively utilize the characteristic transport service of SCTP.

The present invention allows flexible processing of UDP, TCP, and SCTP described above as a softswitch transport protocol according to information requiring network reliability.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention in more detail.

2 is an internal configuration diagram of a soft switch according to an embodiment of the present invention.

The media gateway 300 illustrated in FIG. 2 is a concept of integrating the access gateway 10 and the trunk gateway 30 described in FIG. 1. Although the other softswitch 40 is not shown in FIG. 2, since the other softswitch 40 also communicates in the same manner as the media gateway 300, a detailed description of the other softswitch 40 will be omitted. .

The soft switch mounts an IP protocol 210 (hereinafter referred to as an IP layer) on the network layer which is an OSI 3 layer, and a TCP protocol 220 or below on a transport layer which is an OSI 4 layer above the IP protocol 210 (hereinafter referred to as an IP layer). TCP layer), UDP protocol 230 (hereinafter referred to as UDP layer), and SCTP protocol 240 (hereinafter referred to as SCTP layer), respectively.

By the above structure, when the TCP message based on the TCP protocol is transmitted from the media gateway 300, it is processed by the TCP layer 220, and the UDP layer 230 when the UDP message is transmitted based on the UDP protocol. If an STCP message based on the STCP protocol is transmitted, it is processed by the SCTP layer 240.

Meanwhile, since the TCP protocol and the SCTP protocol guarantee the reliability of the packet, the TCP protocol and the SCTP protocol must connect a session to a specific socket while the packet transmission is terminated. To this end, the present invention provides a socket configured on the upper part of the TCP layer 220. And a session manager 221 for managing sessions for the 223, 224, and 225, and a session manager 241 for managing sessions for the sockets 242 and 243 configured above the SCTP layer 240.

In FIG. 2, although a specific number of sockets 223, 224, 225, 241, and 242 in which sessions are managed by each session managing unit 220 is provided, the number of sockets may be provided as N. It is limited to a specific number for convenience.

On the contrary, since the UDP protocol transmits a packet in a single fashion, the session management of the socket is not necessary, and thus, the session management unit is not provided above the UDP layer 230.

On the other hand, Env (above each socket 223, 224, 225 configured in the TCP layer, an upper socket 231 configured in the UDP layer, and an upper socket of each socket 242, 243 configured in the SCTP layer, respectively. 226, 232, 244 are provided, each of the Env (226, 232, 244) performs a message connection and distribution function between the transport layer and the ACS (250).

The ACS 250 serves as a connection interface and analyzes various transport protocols to perform a call distribution NAT function to a higher call processing service system. When the UDP message is based on the megaco protocol, the ACS 250 includes a mapping table in which the UCP-I / P information allocated to the media gateway 300 that transmits the UDP message is stored, and the TCP or SCTP protocol is provided. When a call setup request of an external device using the service manager also generates a table that maps socket information allocated by the session managers 221 and 241 to source information (outgoing IP address / port) of the external device.

The UCP-I / P (Universal User Call cotrol Processor Internet / PSTN) 260 is a local call originating from the media gateway 300 or a call originating from another soft switch 40, a call processing to another soft switch, or a subscriber call. It manages resources to make it possible. Although FIG. 2 illustrates the UCP-I / P 260 as one module, the UCP-I / P 260 is provided with a plurality of processes, thereby enabling multiprocessing.

The ACS 250 and the UCP-I / P 260 exchange messages using UDP or XIPC. In the present invention, a method of exchanging messages using UDP will be described.                     

The soft switch according to the present invention can process both UDP / TCP / SCTP between the media gateway 300 and the other soft switch 40, but only UDP is used inside the soft switch. The purpose of using TCP / SCTP outside the softswitch is to ensure the reliability of message delivery. This is because the possibility of message loss increases when the message is transmitted using UDP in an IP network (packet network). This may cause a drop in).

On the contrary, if UDP is used in the soft switch, the packet (message) does not have a concern about deterioration in service quality since only the message for the subscriber call processing inside the soft switch exists.

In particular, the ACS 250 and the UCP-I / P 260 preferably define internal messages separately to maintain the unique connectivity of TCP and SCTP. In addition, the ACS 250 processes both UDP messages based on the Megaco Protocol and UDP messages based on the SIP protocol according to their characteristics.

Referring to the signal flow diagram shown in Figures 3 to 5, the signal processing method according to an embodiment of the present invention will be described in detail.

3 is a signal flow diagram illustrating a signal processing procedure based on UDP as a transport protocol.

When the UDP message is transmitted from the media gateway 300, the UDP message is transmitted to the ACS 250 via the IP 210, the UDP 230, the socket 231, and the Env 232 (S2).

The ACS 250 determines whether the UDP message is a SIP protocol message or a megaco protocol message based on the port number to which the UDP message transmitted from the Env 232 is input (S4), and the UDP message is a megaco protocol. If it is confirmed (Yes in S4), the process number corresponding to the originating address included in the UDP message is extracted from the mapping table in which the process number of UCP-I / P is stored for MG (S8).

Subsequently, the ACS 250 sends a UCP-I / P 260 a UDP message including an originating IP address / port number, a destination IP address (UCP-I / P process number) / port number, data, and the like based on UDP. (S10).

However, if it is determined in the SIP protocol that the determination result in S4 (No in S4) refers to the overload state of the UCP-I / P constituting the UCP-I / P 260 to the round-robin method. The internal message including the UDP-based source IP address / port number, the destination IP address (UCP-I / P) / port number, information data, etc. is transmitted to the specific process selected by the specific UCP-I / P (S6). .

4 is a signal flow diagram illustrating a signal processing procedure based on TCP as a transport protocol.

In the case of the TCP protocol, the soft switch and the media gateway 300 operate in a server-client concept. Due to this, the specific media gateway 300 transmits a TCP connection request message to the soft switch at the time of initialization (S20).

The session management unit configured in the upper part of the TCP layer 220 by the TCP connection request message allocates any socket among the managed sockets (S22), and the socket allocation result including the allocated socket number and originating IP address / port information. To the ACS 250 (S24).                     

The ACS 250 receiving the socket allocation result generates and manages a mapping table for extracting external equipment corresponding to the socket number by mapping the socket number to the originating IP address / port (S26). The TCP connection completion notification message processed by the UDP is transmitted to the UCP-I / P 260 (S28).

Subsequently, the UCP-I / P 260 receiving the TCP connection completion notification message also maps the socket number to the originating IP address / port and generates and manages a mapping table for extracting an external device corresponding to the socket number ( S30).

In this state, when a TCP message is transmitted from the media gateway 300, the TCP message is transmitted via the IP 210, the TCP 220, the allocated socket (e.g., 223), and the Env 226. Is transmitted to the ACS 250 (S32), and the ACS 250 processes the socket number through which the TCP message is transmitted and the information data included in the TCP message on the basis of UDP, thereby making a UDP call message accordingly. It transmits to / P (260) (S34). Here, the TCP 220 transmits the input TCP message to the socket previously allocated by referring to the socket allocation result of the session manager 221.

The UCP-I / P 260 receiving the socket number and the information data checks the media server 300 corresponding to the socket number in the mapping table and performs an application to be provided to the identified media server 300. The application execution result is transmitted to the media gateway 300.

As a result, the soft switch corresponding to the present invention can extend an external TCP connection in a connection oriented manner while performing NAT call distribution (Megaco / SIP).                     

5 is a signal flow diagram illustrating a signal processing procedure based on SCTP as a transport protocol.

In the case of the SCTP protocol, similar to the TCP protocol, since the soft switch and the media gateway 300 operate in a server-client concept, the specific media gateway 300 transmits an SCTP connection request message to the soft switch at the time of initialization. S40).

The session manager 241 configured at the upper part of the SCTP layer 240 by the SCTP connection request message allocates an arbitrary socket among the sockets being managed (S42), and includes the allocated socket number and the originating IP address / port information. The socket allocation result is transmitted to the ACS 250 (S24). At this time, the session manager 241 notifies the socket allocation result to the SCTP layer 240 as well.

The ACS 250 receiving the socket allocation result generates and manages a mapping table for mapping the socket number to the originating IP address / port and extracting an external device corresponding to the socket number (S46). The SCTP connection completion notification message corresponding to the allocation result is processed by UDP and transmitted to UCP-I / P 260 (S28).

Subsequently, the UCP-I / P 260 receiving the SCTP connection completion notification message generates and manages a mapping table for the source IP address / port for the socket number (S50).

In this state, when a SCTP message is sent from the media gateway 300, the SCTP message is sent to the ACS 250 via IP 210, SCTP 240, assigned sockets (eg, 242), and Env 244. (S52), the ACS 250 processes the socket number to which the SCTP message is transmitted and the information data included in the TCP message on the basis of UDP, the UDP call message according to the UCP-I / P ( 260) (S54).

The UCP-I / P 260 receiving the socket number and the information data checks the media server 300 corresponding to the socket number in the mapping table and performs an application to be provided to the identified media server 300. The application execution result is transmitted to the media gateway 300.

In the present invention, the source code of the UDP message transmitted between the ACS 250 and the UCP-I / P 260 is as shown below.

In the present invention, the message format transmitted between the ACS 250 and the UCP-I / P 260 is designated as UDP, but may also be designated as an XIPC message format that can be used as an internal message format. Since the XIPC message has a smaller amount of data that can be transmitted than the UDP message, it is desirable to determine the internal message format between the ACS 250 and the UCP-I / P 260 in consideration of this point.

According to the present invention as described above, there is an effect that the soft switch can flexibly cope with the interworking with external equipment (access gateway, trunk gateway, other soft switch, etc.) providing a single protocol by providing a multi-protocol.

In addition, only the UDP protocol needs to be considered when designing a higher-level application, thereby reducing the complexity and improving performance in system design.

On the other hand, the present invention is not limited to the above-described embodiment, but can be modified and modified within the scope not departing from the gist of the present invention, such modifications and changes should be regarded as belonging to the following claims. will be.

Claims (14)

A TCP layer configured above the IP layer to process TCP messages transmitted from an external device; A UDP layer configured above the IP layer to process a UDP message transmitted from the external device; An SCTP layer configured above the IP layer to process an SCTP message transmitted from the external device; A TCP session manager configured on the TCP layer to perform socket management for TCP message transmission; An SCTP session manager configured on the SCTP layer to perform socket management for SCTP message transmission; An ACS for processing a UDP message received from the UDP layer, a TCP message received from the TCP layer, and an SCTP message received from the SCTP layer into a UPD message and transmitting the same to a UCP-I / P; And UCP-I / P which analyzes the UPD message and manages resources for a predetermined call processing requested from the external device based on the analysis result Soft switch with multi-transport protocol processing, including. The method of claim 1, wherein the external equipment is Soft switch with multi-transport protocol processing, characterized in that the device uses the UDP protocol as a transport protocol. The method of claim 1, wherein the external equipment is Soft switch with multi-transport protocol processing, characterized in that the device uses the TCP protocol as a transport protocol. The method of claim 1, wherein the external equipment is Soft switch with multi-transport protocol processing, characterized in that the equipment using the SCTP protocol as a transport protocol. The apparatus of claim 3 or 4, wherein the external equipment is Soft switch with a multi-transport protocol processing function, characterized in that for transmitting the connection setup request message to the soft switch at the initial startup. The method of claim 5, wherein the TCP session management unit When a connection establishment request message is transmitted from the external device via the TCP layer, a socket among the sockets being managed is allocated to the external device, and the socket allocation result is transmitted to the TCP layer and the ACS. Soft switch with multi-port protocol handling. The method of claim 6, wherein the ACS is Using the socket number and the originating IP address / origination port included in the socket allocation result, a table for mapping the originating IP address / outgoing port to the socket number is generated, and the socket allocation result is processed by UDP to generate the UCP-. When the TCP message is transmitted from the external device, a UDP call message including the information data included in the TCP message and the socket number allocated to the TCP message is transmitted to the UCP-I / P. Thing Soft switch with multi-port protocol processing. The method of claim 7, wherein the UCP-I / P After generating a table for mapping an originating IP address / outgoing port to a socket number based on the UDP-based socket allocation result, when a UDP call message is transmitted from the ACS, information of the external device is extracted from the mapping table. Soft switch with a multi-transport protocol processing function, characterized in that for performing the resource management for the call processing requested from the external equipment. The method of claim 5, wherein the SCTP session management unit When a connection establishment request message is transmitted from the external device via the SCTP layer, a specific socket among the managed sockets is allocated to the external device, and the socket allocation result is transmitted to the SCTP layer and the ACS. Soft switch with multi-transport protocol handling. The method of claim 9, wherein the ACS is Using the socket number and the originating IP address / origination port included in the socket allocation result, a table for mapping the originating IP address / outgoing port to the socket number is generated, and the socket allocation result is processed by UDP to generate the UCP-. Transmitting to the UCP-I / P a UDP call message including information data included in the SCTP message and a socket number allocated for the TCP message when an SCTP message is transmitted from the external device. Thing Soft switch with multi-port protocol processing. The method of claim 10, wherein the UCP-I / P After generating a table for mapping an originating IP address / outgoing port to a socket number based on the UDP-based socket allocation result, when a UDP call message is transmitted from the ACS, information of the external device is extracted from the mapping table. Soft switch with a multi-transport protocol processing function, characterized in that for performing the resource management for the call processing requested from the external equipment. The method of claim 1, wherein the ACS And a mapping table capable of extracting a designated UCP-I / P process number for the external device using the megaco protocol. The method of claim 12, wherein the ACS is If the UDP message transmitted from the UDP layer is based on the megaco protocol, the destination IP address corresponding to the originating IP address / port information extracted from the UDP message and the UCP-I / P process number extracted from the mapping table. Soft switch with multi-port protocol processing function, characterized in that the / port, and the information data is processed by UDP and transmitted to the UCP-I / P. The method of claim 1, wherein the ACS is If the UDP message transmitted from the UDP layer is based on the SIP protocol, a round-robin may be processed by processing the originating IP address / port information, the destination IP address / port, and the information data included in the UDP message into UDP. Soft switch with a multi-transport protocol processing function, characterized in that for transmitting to the UCP-I / P.

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