KR20090024051A - Method and apparatus for data transferring using stream control transfer protocol - Google Patents

Abstract

A method and an apparatus for transmitting data are provided to improve reliability of message transmission in a network congestion situation by disabling a PRSCTP(Partial Reliable-SCTP) service as occasion demands. A data transmission apparatus includes a connection setting unit(22), a control request receiver(24) and a service controller(26). The connection setting unit sets the SCTP connection with at least one node by using the SCTP. The control request receiver receives the service control request about the set SCTP connection from at least one application(40) by using the extended socket option(30). The service controller disables or enables the service about the SCTP connection which is set up according to the received service control request.

Description

Method and apparatus for data transfer using SCP TECHNICAL FIELD

The present invention relates to a data transmission method and apparatus, and more particularly, to a method and apparatus for transmitting data using Stream Control Transmission Protocol (SCTP).

Recently, the Stream Control Transfer Protocol (SCTP) call has attracted attention as a next generation transport layer protocol to replace TCP / UDP. Despite the various requirements for real-time multimedia services of the Internet, the transport layer protocol in the Internet has been limited to TCP and UDP until recently. However, TCP and UDP-based Internet protocols are not suitable for providing a telephone service or a multimedia streaming service provided in a conventional PSTN network.

SCTP is a transport layer protocol proposed by the IETF SIGTRAN Working Group in October 2000 as a standard for transmitting signaling messages used in PSTN networks over the Internet's IP network. SCTP is a protocol with the message-oriented nature of UDP and connection-oriented nature of TCP, which enables reliable data transmission and is designed to be safe against DOS (Denial of Service Attacks) attacks that can be issued when establishing an association. . It also provides multi-streaming for sending multiple application streams over one connection and multi-homing for binding multiple network IP addresses.

In addition to Voice over IP (VoIP) signaling, SCTP is a high-reliability security application such as web applications that deliver multimedia, authentication, authorization, accounting (AAA), and mission-critical demanding real-time reliability. It can be used as a sub-protocol such as application service, and it is expected to be used as a sub-protocol for easily providing handover function in all-IP based mobile communication network which is recently being issued.

The IETF is currently working on the establishment of the SCTP framework, and is working on implementation, verification, and expansion of additional features. A further extension of SCTP that is currently under discussion includes the ability to provide partial reliability.

1) PRSCTP

In particular, PRSCTP (Partial Reliable SCTP), which provides partial reliability, is designed for real-time applications and stops error control for time-critical streams during SCTP data transmission and immediately sends data to the application layer. Provides the ability to deliver.

In order to use the PRSCTP function, it is necessary to negotiate whether to support the PRSCTP function from the establishment of the connection, that is, the initialization phase, between SCTP transmitting and receiving nodes. Information on whether PRSCTP is supported is exchanged with INIT and INIT-ACK messages during connection establishment. Once data transmission has begun, the transmitting node may notify the other end node as necessary to stop the reliability provisioning function for data prior to a specific Transmission Sequence Number (TSN) number. When the receiving node receives the PRSCTP signal, it directly sends the corresponding chunks of data in its buffer to the upper application layer. This extension can be used to transfer application data that is primarily time-constrained.

2) chunk bundling

SCTP, on the other hand, may include multiple chunks in the SCTP packet to transmit. If the chunk bundling attribute is enabled, SCTP adds the chunk to the message with a common header. The message may be a user data or SCTP control message. SCTP always supports chunk bundling by default. Enabling or disabling chunking bundling merely determines whether to wait for the minimum specified time for the next message to be bundled. If you enable chunking bundling, the chunk waits for the time that the next message is bundled.

The above-described functions have their own advantages, but the above-described functions remain the same until the connection is released when the connection is established at the initialization stage when the connection is established. That is, while the established connection is maintained, the initially set function is maintained as it is, and while the connection is maintained, there is a problem in that the user cannot control to enable or disable the aforementioned function by a message unit as necessary. .

In actual real-time multimedia data transmission, there may be messages (eg security-related messages) that necessarily require reliable delivery, depending on the nature of the message or application, and messages that allow unreliable delivery for time-sensitive applications (e.g., For example, a real-time data message). In addition, for applications with imminent time requirements, there may be a need to disable bundling.

Accordingly, the present invention provides a method and apparatus for data transmission using SCTP that can control a user to enable / disable the PRSCTP function or the chunk bundling function according to the aforementioned needs.

According to an aspect of the present invention, a data transmission method using a Stream Control Transmission Protocol (SCTP) includes: a) establishing an SCTP connection between at least two nodes using SCTP; b) receiving a service control request for an established SCTP association from an application using an extended socket option; And c) enabling or disabling a service for an established SCTP connection according to the received service control request.

Here, the service control request for the SCTP connection may include a partial reliable SCTP service control request or a bundling service control request.

In addition, the extended socket option may provide a standardized application program interface (hereinafter referred to as an API) for an application to access the kernel, and the extended socket option may include an SCTP_ENABLE_PRSCTP variable or an SCTP_ENABLE_BUNDLING variable.

At this point, the SCTP_ENABLE_PRSCTP variable or the SCTP_ENABLE_BUNDLING variable may have a Boolean value.

In addition, the extended socket option may include a variable for retrieving the number of bound address lists on a multi-homed SCTP node supporting multiple IP addresses,

The extended socket option may include a variable to retrieve a list of bound addresses on a multihomed SCTP node supporting multiple IP addresses.

On the other hand, according to another aspect of the present invention, a data transmission apparatus using a stream control transmission protocol (SCTP), Connection setting unit for establishing an SCTP connection with at least one node using SCTP; A control request receiver configured to receive a service control request for the established SCTP association using an extended socket option from at least one application; And a service controller for enabling or disabling the service for the SCTP connection established according to the received service control request.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention; In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted when it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to intention or custom of a user or an operator. Therefore, the definition should be made based on the contents throughout the specification.

For convenience of description, terms used in one embodiment of the present invention are summarized as follows.

Multihoming is a key feature of SCTP, which refers to the ability of one SCTP endpoint node to support multiple IP addresses. The SCTP connection allows multiple IP addresses to be used at the same time so that if a network failure occurs during the connection, the connection is maintained via an alternate path (alternative IP address).

Multistreaming refers to a function of dividing data to be transmitted into a plurality of streams having attributes delivered in an independent order. In the connection establishment step, the transmitting end notifies the receiving side of the number of streams to be transmitted, and an independent ordering function is provided for each stream in the transmitting step. Accordingly, the loss of a message in one stream only affects the beginning of the stream but does not affect the transmission of other streams.

The Partial Reliable SCTP Service is a service that specifies, on a message-by-rule basis, how long a transport service attempts to send a message to a receiver. Accordingly, the time-critical streams during the SCTP data transmission are provided with a function to stop error control and immediately transfer data to the application layer.

SCTP stream refers to a series of user messages that must be delivered sequentially from SCTP to the Upper Layer Protocol.

An embodiment of the present invention proposes a method for allowing a user to enable or disable a PRSCTP service as needed. To this end, the present invention provides a new socket option.

1 is a reference diagram showing the structure of an SCTP protocol according to an embodiment of the present invention.

As shown in FIG. 1, SCTP is located between the application layer 40 and the network layer 10 as a protocol of the transport layer. SCTP receives application data between SCTP nodes through API (Application Programming Interface) 30 and transmits the data through an IP network. Each SCTP terminal can use multiple IP addresses in one SCTP connection.

SCTP provides multihoming and multistreaming capabilities for message transfer between two points. The SCTP connection session between two SCTP points is called "SCTP association". The transmission procedure for a particular SCTP connection is divided into connection establishment phase (or initialization phase), data transmission phase, and shutdown phase.

An SCTP packet or Protocol Data Unit (PDU) consists of a common header and several chunks, each of which contains control information or application data. Each data is sequentially transmitted in the SCTP stream, and multi-homing characteristics can be used to recover from a network failure.

An apparatus for transmitting data using SCTP according to an embodiment of the present invention provides an extension API 30 to enable a user to control the enable or disable of the aforementioned PRSCTP service or bundling service. The extension API 30 includes a new socket option for enabling or disabling the PRSCTP service or bundling service. By setting or clearing newly defined socket option variables, the user can control the service while the SCTP connection is maintained.

2 is a reference diagram illustrating a packet structure of an SCTP according to an embodiment of the present invention.

Referring to FIG. 2, the header of the SCTP packet includes a sender port number, a recipient port number, a verification tag, and checksum information for the entire packet. The verification tag is assigned per SCTP connection and used as the session identifier.

One SCTP packet may include multiple control chunks and data chunks, and in the case of data chunks, a transmission sequence number (TSN) and a stream sequence (SSN) for the corresponding data chunk together with type and length information. Number) It is used for error control and flow control including number. SCTP uses control chunks with data chunks, and the number of control chunks can increase with SCTP extension in the future.

3 is a block diagram of a data transmission apparatus using SCTP according to an embodiment of the present invention.

Referring to FIG. 3, an apparatus for transmitting data using SCTP according to an embodiment of the present invention includes a connection setting unit 22, a control request receiving unit 24, and a service control unit 26. The data transmission apparatus using the SCTP according to an embodiment of the present invention may control the PRSCTP service or the bundling service of the SCTP connection 10 through the extension API 30 including the socket option function on the application program 40. .

The connection setting unit 22 establishes an SCTP connection with at least one node using SCTP. Information for the PRSCTP service is exchanged between nodes with INIT and INIT-ACK messages during the SCTP connection establishment process.

The control request receiver 24 receives a service control request for the SCTP connection established using the extended socket option 30 from at least one application. The service control request for the SCTP connection may include a partial reliable SCTP service control request or a bundling service control request.

The extended sockets option here provides a standardized way for applications to access the kernel. Since the SCTP transport layer is implemented as part of the kernel module, it can only be accessed by the socket API. Accordingly, the extended socket API 30 according to an embodiment of the present invention may include the SCTP_ENABLE_PRSCTP variable or the SCTP_ENABLE_BUNDLING variable as the socket option variable. The SCTP_ENABLE_PRSCTP variable is an extension API for enabling / disabling a PRSCTP service, and the SCTP_ENABLE_BUNDLING variable is an extension API for enabling / disabling a bundling service. The SCTP_ENABLE_PRSCTP variable or the SCTP_ENABLE_BUNDLING variable may have a Boolean value for setting or clearing each service.

The extended socket option may also include a variable to retrieve the number of bound address lists or a variable to retrieve the bound address list on a multi-homed SCTP node supporting multiple IP addresses.

The service controller 26 enables or disables the PRSCTP service or bundling service for the SCTP connection established according to the received service control request as described above. Accordingly, after the SCTP connection is established, even while the SCTP connection is maintained, the user can control the SCTP connection by using the socket option variables defined in the extension API 30.

One embodiment of the present invention provides a PRSCTP extended service function for removing a PRSCTP service when it is not needed at an SCTP endpoint. That is, according to an embodiment of the present invention, when the PRSCTP service is not needed or when the PRSCTP service is to be released, a mechanism for setting the PRSCTP service through a socket option that can access the kernel of the operating system is provided.

According to an embodiment of the present invention, the following socket option variables may be added to the SCTP extension API.

1) SCTP_ENABLE_PRSCTP

Variables that control the application to enable / disable the PRSCTP service

2) SCTP_ENABLE_BUNDLING

Variables that control the application to enable / disable bundling services

These variables may be input from the user or application program as configuration information for changing the settings of the SCTP connection.

More specifically, Fig. 4 and Fig. 5 show an example of the service control application of the data transmission apparatus according to an embodiment of the present invention.

Referring to FIG. 4, the SET socket option for the SCTP socket can be extended to include the SCTP_ENABLE_PRSCTP variable. The socket option has a Boolean variable value that enables / disables partial reliability support service (PRSCTP). When the data transmission device using the SCTP receives this request, it sends an INIT chunk to the connected node in order to set or release the partial reliability support service (PRSCTP) as required by the application. You can change whether or not to support the RPSCTP service on a socket basis while SCTP connection is maintained. The user may control whether the SCSC connection supports the PRSCTP service through the extension API 30 by setting or clearing the SCTP_ENABLE_PRSCTP variable value on the application program 40.

Referring to FIG. 5, the SET socket option for the SCTP socket may be extended to include the SCTP_ENABLE_BUNDLING variable. SCTP_ENABLE_BUNDLING, used by an application, is an extended socket option variable that enables / disables chunking bundling for each connected socket. It has a Boolean value that enables / disables bundling. This may affect the behavior of SCTP while bundling user messages or SCTP control messages. The user may control whether or not the bundling service of the SCTP connection is supported through the extension API 30 by setting or clearing the SCTP_ENABLE_BUNDLING variable value on the application program 40.

In addition, according to an embodiment of the present invention, the following user provisions for enabling or disabling the PRSCTP service function or bundling function of SCTP may be provided.

1) A new socket option to set the PRSCTP service, thus providing a message transfer that provides partial reliability, depending on the application program's needs, or a fully reliable message transfer even under network congestion.

2) A new socket option, SCTP_BOUND_ADDR_NUM, to GET the number of bound address lists for multihoming.

3) A new socket option, GTP_BOUND_ADDR_LIST, to GET the list of bound addresses for multing homeing.

These extended socket option variables provide a standardized way for applications to access the modular kernel. These added socket options will be consistent with the application interface uniformity according to the SCTP standard.

In short, one embodiment of the present invention provides a new socket option for controlling the PRSCTP service and the bundling service. It also includes a socket option for bound address lookup at the SCTP end node for multihoming. Accordingly, the data transmission apparatus using the SCTP according to an embodiment of the present invention may have the following characteristic functions.

1) Multi homing

2) Multi Streaming

3) Partial reliability

4) Chunk Bundling

SCTP is part of the kernel module and can only be accessed by the socket API. SCTP is a transport layer protocol. Basically, PRSCTP service and bundling service are enabled. However, there may be users who do not require PRSCTP services or bundling services. In addition, some application programs may not be able to tolerate such delays because the time associated with bundling is very important depending on the application program. Furthermore, it may be necessary to enable the PRSCTP service when the window size of the receiving side is exhausted.

As described in detail above, according to an embodiment of the present invention, a means for enabling / disabling and controlling a PRSCTP service or a bundling service according to a characteristic of a message or an application program is provided.

6 is a flowchart illustrating a data transmission method using SCTP according to an embodiment of the present invention.

Referring to FIG. 6, in order to transmit data using SCTP according to the present invention, first, SCTP connection between SCTP nodes is established (S500). The service control request for the SCTP connection established from the application program is received using the above-described extended socket option (S510). In this case, an extended socket option for controlling a PRSCTP service or a bundling service may be used. The PRSCTP service or bundling service for the SCTP connection established according to the received service control request is enabled or disabled (S520).

According to one embodiment of the present invention described above, there is provided a data transmission apparatus and method capable of controlling a user to enable / disable a PRSCTP service. Accordingly, by disabling the PRSCTP service as necessary, it is possible to provide complete reliability in message transmission even in a network congestion situation.

In addition, according to one embodiment of the present invention, new socket options for controlling the PRSCTP service and the bundling service are provided.

Furthermore, a method for retrieving a bound address list at an SCTP end node supporting multi-homing is provided.

According to an embodiment of the present invention, in addition to the basic operation of the SCTP that is set globally at the time of establishing the SCTP connection, there is provided a method for controlling the SCTP operation based on the socket while the SCTP connection is maintained.

So far, the present invention has been described with reference to the embodiments. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

1 is a reference diagram showing the structure of an SCTP protocol according to an embodiment of the present invention;

2 is a reference diagram illustrating a packet structure of an SCTP protocol according to an embodiment of the present invention;

3 is a block diagram of a data transmission apparatus using SCTP according to an embodiment of the present invention;

4 and 5 are examples of a service control application of a data transmission device according to an embodiment of the present invention;

6 is a flowchart illustrating a data transmission method using SCTP according to an embodiment of the present invention.

Claims (14)

In the data transmission method using the Stream Control Transfer Protocol (hereinafter referred to as SCTP), a) establishing an SCTP connection between at least two nodes using the SCTP; b) receiving a service control request for the established SCTP association from an application using an extended socket option; And c) enabling or disabling a service for the established SCTP connection according to the received service control request. The method of claim 1, The service control request for the SCTP connection includes a partial reliable SCTP service control request or a bundling service control request. The method of claim 1, The extended socket option is a data transmission method using SCTP to provide a standardized application program interface (API) for the application to access the kernel. The method of claim 1, The extended socket option is a data transmission method using SCTP including a SCTP_ENABLE_PRSCTP variable or SCTP_ENABLE_BUNDLING variable. The method of claim 4, wherein The SCTP_ENABLE_PRSCTP variable or SCTP_ENABLE_BUNDLING variable is a data transmission method using SCTP having a Boolean value. The method of claim 1, The extended socket option includes a variable for retrieving the number of bound address lists on a multi-homed SCTP node supporting a plurality of IP addresses. The method of claim 1, The extended socket option includes a variable for retrieving a list of bound addresses on a multihomed SCTP node supporting a plurality of IP addresses. In the data transmission apparatus using the Stream Control Transfer Protocol (hereinafter referred to as SCTP), A connection establishment unit configured to establish an SCTP connection with at least one node using the SCTP; A control request receiver configured to receive a service control request for the established SCTP association using an extended socket option from at least one application; And And a service controller for enabling or disabling a service for the established SCTP connection according to the received service control request. The method of claim 8, The service control request for the SCTP connection includes a partial reliable SCTP service control request or a bundling service control request. The method of claim 8, The extended socket option is an apparatus for transmitting data using SCTP that provides a standardized means for an application to access the kernel. The method of claim 8, The extended socket option may include an SCTP_ENABLE_PRSCTP variable or an SCTP_ENABLE_BUNDLING variable. The method of claim 11, The SCTP_ENABLE_PRSCTP variable or SCTP_ENABLE_BUNDLING variable is a data transmission device using SCTP having a Boolean value The method of claim 8, The extended socket option includes a variable for retrieving the number of bound address lists on a multi-homed SCTP node supporting a plurality of IP addresses. The method of claim 8, The extended socket option includes a variable for retrieving a list of bound addresses on a multi-home SCTP node supporting a plurality of IP addresses.

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