KR100462025B1 - Apparatus and method of application level framing for media gateway control protocol - Google Patents

Abstract

An apparatus and method for application level framing of a media gateway control protocol according to the present invention include a media gateway that is located between different networks, performs media conversion with each other, and controls the media gateway to provide a service. An application level framing apparatus using a media gateway control protocol (hereinafter referred to as Megaco protocol) in a media gate control period, the apparatus comprising: a transaction request processor for requesting execution of an arbitrary instruction to a large station; A transaction execution processor that executes a command requested from the power and informs the power of the result; A Megaco processing processor that encodes a transaction message required by the transaction request processor or the transaction execution processor into a Megaco message to be transmitted to a large power, and decodes a Megaco message received from the large power; A transaction management table for storing and managing message information transmitted and received from the Megaco processing processor to a power station; And an external signal transfer processor that transmits a Megaco message from the Megaco processing processor to a power station and delivers the Megaco message received from the power to the Megaco processing processor.

According to the present invention, it is expected to combine the effective ALF method with the fast performance of UDP to enable the fast and effective exchange of Megaco protocol messages between MGC and MG.

Description

Apparatus and method of application level framing for media gateway control protocol

The present invention relates to ALF (Application Level Framing) in Megaco (Media Gateway Control Protocol), in particular, to solve the problem of packet loss, delay, redundancy that occurs when applying Megaco over UDP (User Datagram Protocol) Megaco's ALF device and method.

Megaco, also called H.248, is a standard protocol between MGC (Media Gateway Controller) and MG (Media Gateway), which is used when MGC controls MG of various applications.

This protocol is a communication method between a media gateway (hereinafter referred to as MG) and a media gateway controller (MGC) that changes the media format required for the circuit-switched network to the media format required for the packet-switched network. Define.

Megaco is used to set up, manage, or terminate calls between multiple ends, which is an evolution of MGCP.

In addition, the next generation network is moving toward accommodating various services through one packet network.

At this time, the MG and MGC described above are necessary to accommodate the existing public switched telephone network (PSTN) network in the packet network.

At this time, the MG is an IS (Intermediate System) between the different networks to perform the media conversion between the manganese, MGC serves to control this through Megaco / H.248.

For the method of creating a connection of the Megaco protocol between the MG and the MGC, a process required for the connection between the source and destination media gateways is disclosed in Korean Patent Application No. 10-2000-0034451 (Method for creating a media gateway control protocol connection in a voice Internet protocol network). A method of reducing is proposed.

The above patent suggests how to create an outgoing and incoming connection between MG and MGC, thereby reducing the necessary connection, thereby reducing the load between MG and MGC.

1 is a block diagram showing the configuration of a next-generation network.

Referring to FIG. 1, a Next Generation Network (NGN) includes a RG (Residential Gateway) 111, an AG (Access Gateway) 112, and a TG (centered around a packet network 100). Trunk Gateways (113) are connected between the existing PSTN service device FAX 131, Private Branch Exchange (PBX) 132, LEX (Local Exchange) 133 and the packet network, MGC (121, 122) ) Is configured to control RG 111, AG 112 and TG 113 via Megaco.

In addition, as shown in FIG. 1, the thick arrow indicates the Megaco / H.248 signal, the dotted line indicates the signaling, and the thin solid line indicates the transmission and reception of user data.

In addition, the RG 111 is directly connected to the subscriber analog line of the PSTN to carry voice data on the packet network, and the AG 112 is a PBX (voice subscriber access device), which is an aggregated voice subscriber interface device (Primary Rate Interface in ISDN). 132) or PSTN switch devices such as subscriber multiplexing equipment to carry voice data on the packet network.

In addition, the TG 113 is connected to the local exchange to perform media conversion between the local exchange and the packet network.

The RGs 111, AG 112, and TG 113 are connected to the MGCs 1 and 2 121 and 122 and are controlled by the MGCs 1 and 2 121 and 122 through Megaco.

In addition, signaling is performed between the MGC 1 121 and the MGC 2 122 using a protocol such as a Session Initiation Protocol (SIP).

The instruction processing mechanism between the MGC 1 and 2 (121, 122) and the MG RG (111), AG (112), TG (113) is as follows.

2 is a flowchart of message transmission and reception between MGC and MG.

Referring to FIG. 2, when the MGC 210 requests execution of an instruction to the MG 220 between the MGC 210 and the MG 220, the MGC 210 first requests a command to be executed by the MG 220. It transmits (S201).

Then, the MG 220 performs the command according to the request of the MGC 210 and transmits a transaction reply message (Transaction Reply) to the MGC 210 (S203). At this time, if the MG 220 is likely to delay the execution of the command, it sends a transaction maintenance message (Transaction Pending) to the MGC 210 (S202), it can be informed of the fact, the MG 22 the transaction response message ( If the MGC 210 has received the S203, it may request the MGC 210 to send a transaction response confirmation message (Transaction ResACK) (S204).

In addition, even when the MG 220 requests the command to the MGC 210, the same command is performed as described above. When the MG 220 sends a transaction request message, the MG 220 includes a transaction identifier that uniquely identifies the transaction. The response (transaction hold message, transaction response message) message to the transaction request message uses the same transaction identifier.

As described above, the MGC 210 and the MG 220 are configured on various transports such as Transmission Control Protocol (TCP), UDP, Stream Control Transmission Protocol (SCTP), Signaling ATM Adaption Layer (SAAL) over Asynchronous Transfer Mode (ATM), and the like. You can use Megaco.

However, in connection type transports such as TCP, SCTP, SAAL over ATM, etc., since there is its own framing method, problems such as packet delay and packet loss do not need to be involved at the application level. However, when UDP is used, packet delay is applied at the application level. Problem to be solved, such as packet loss.

In order to solve the above problems, the present invention provides an Application Level Framing (ALF) method for solving problems such as packet delay and packet loss when using Megaco protocol over UDP transport. It is an object of the present invention to provide an ALF apparatus and method of the Megaco protocol in a UDP transport that can solve the problem of packet loss and packet delay.

1 is a block diagram showing the configuration of a next-generation network.

2 is a flowchart of message transmission and reception between the MGC and the MG.

3 is a block diagram showing the configuration of the ALF device of the Megaco protocol according to an embodiment of the present invention.

4 is a flowchart of an ALF method applied to a transaction requestor in the configuration of FIG. 3 according to an embodiment of the present invention.

5 is a flowchart illustrating an ALF method applied to a transaction performer in the configuration of FIG. 3 according to an embodiment of the present invention.

6 is a diagram illustrating a configuration of a transaction management table according to an embodiment of the present invention.

<Brief description of the main parts of the drawings>

100: packet network 111, 112, 113: MG

121, 122: MGC 131: POTS

132: PBX 133: LEX

301: transaction request processor 302: transaction execution processor

303: Megaco Protocol Processing Processor

304: external signal transfer processor 305: transaction management table

305a: transaction transfer table 305b: transaction response table

The ALF device of the Megaco protocol in the UDP transport according to the present invention,

A media gateway control protocol (hereinafter referred to as Megaco protocol) is located between media networks that are located between different networks and perform data transmission and reception by converting media to each other, and a media gate control period for providing services by controlling the media gateway. An application level framing device, comprising: a transaction request processor for requesting execution of an arbitrary command to a large power; A transaction execution processor that executes a command requested from the power and informs the power of the result; A Megaco processing processor that encodes a transaction message required by the transaction request processor or the transaction execution processor into a Megaco message to be transmitted to a large power, and decodes a Megaco message received from the large power; A transaction management table for storing and managing message information transmitted and received from the Megaco processing processor to a power station; And an external signal transfer processor that transmits a Megaco message from the Megaco processing processor to a power station and delivers the Megaco message received from the power to the Megaco processing processor.

Preferably, the transaction message, the transaction request message (Transaction Request) for transmitting to request the execution of any command to the power; A transaction reply message for performing a command requested from the power and transmitting the result to the power; In the execution of a command requested from the power, a transaction holding message for informing that the execution of the command is not finished yet; And a transaction response acknowledgment message (Transaction ResACK) for informing the corresponding station of acknowledgment of the transaction response message transmitted from the power to the transaction request message.

Preferably, the transaction management table, the transaction transmission table for storing and managing a transaction request message sent by the Megaco processing processor to the power; And a transaction response table for storing and managing a transaction response message transmitted to the corresponding power station according to the execution result of the instruction execution of the transaction request message received by the megaco processing processor from the power station.

Preferably, the transaction transmission table, Retransmission timer for retransmitting the transaction request message, if there is no transaction response message for the transaction request message for a certain time; And a response maintenance timer for storing a corresponding transaction response message for a predetermined time to determine duplicate reception of the response message for the transaction request message.

Advantageously, said transaction transfer table comprises: a transaction identifier in accordance with an instruction of said transaction request message; A corresponding transaction request message encoded into the Megaco message; Information on the number of retransmissions of the transaction request message and information on whether to receive a transaction response message for the transaction request message; And transmission time information of the transaction request message.

Preferably, the transaction response table, the maintenance timer for informing the counterpart at a predetermined time period that the execution of the transaction request message received to the power station; And a long timer for performing a command on a transaction request message received from the power station, and temporarily storing a transaction response message transmitted to the power station for a predetermined time.

Advantageously, said transaction response table comprises: a transaction identifier of a transaction response message for a result of performing a transaction request message received from said power; A corresponding transaction response message encoded into the Megaco message; Information on whether a response confirmation message from the power station for the corresponding transaction response message is required; And information on whether to receive a transaction response confirmation message according to whether the response confirmation message is required.

In the present invention, the ALF method is independently applied to a person who requests a transaction and a person who executes the command by receiving a transaction request. Hereinafter, the ALF applied to the transaction requester is called the transaction requester ALF, and the ALF applied to the transaction executor is called the transaction performer ALF.

In addition, Megaco's transaction requester application level framing method according to the present invention, the media gateway (hereinafter referred to as MG) which is located between different networks, and performs data conversion by mutual media conversion, and controls the media gateway In the application level framing method applied to a transaction requestor requesting the execution of instructions using a media gateway control protocol (hereinafter referred to as `` megaco protocol '') between the media gate controller (hereinafter referred to as MGC) that provides a service. MGC) encodes and transmits a transaction request message including a command for requesting execution to MGC (MG) as a Megaco protocol message, stores the transaction request message in a transaction transmission table for transaction request message management, and then stores the MGC. Response message from (MG) And then waits; (b) the MG (MGC) receiving a response message from the MGC (MG), and determining the type of the response message; (c) determining whether a transaction response acknowledgment message is necessary when the response message is a transaction response message indicating a result of the execution of the transaction request message; And (d) if it is necessary to transmit a response confirmation message for the transaction response message, the MG (MGC) transmitting a response confirmation message for the transaction response message to the MGC (MG). do.

Preferably, in the step (a), the MG (MGC) transmits a transaction request message to the MGC (MG), and if a response message is not received for a predetermined time, the MG (MGC) again sends the transaction request message. Setting a retransmission timer for retransmission to the MGC (MG).

Preferably, in the step (b), if it is determined that the response message is a transaction maintenance message informing that the processing is in progress for the transaction request message, the MG (MGC) is a transaction response message for a predetermined time. Determining whether is received; And if a transaction response message for the transaction is not received for a predetermined time and the retransmission timer expires, the MG (MGC) retransmits the corresponding transaction request message and resets the retransmission timer for preventing retransmission for a predetermined time. Increasing the number of retransmission information.

Preferably, if the maximum number of retransmissions for the transaction request message is exceeded, the MG (MGC) includes performing a failure processing procedure for the transaction request.

In addition, Megaco's transaction performer application level framing method according to the present invention, located between the different networks, the media gateway (hereinafter referred to as MG) to perform data transmission and conversion between the media to control the media gateway In the application level framing method applied to a transaction performer for receiving a command execution request using a media gateway control protocol (hereinafter referred to as Megaco) between the media gate controller (hereinafter referred to as MGC) to provide a service,

(a) the MGC (MG) receiving a transaction request message which is an instruction processing request message from the MG (MGC), and determining whether the corresponding transaction request message has been repeatedly received; (b) If it is determined that the corresponding transaction request message has been repeatedly received, the MGC (MG) executes a command according to the corresponding transaction request message, thereby informing the MG (MGC) of the transaction response. Determining whether a message has been sent; (c) retransmitting the transaction response message to the MG (MGC) when a command according to the transaction request has already been executed and a transaction response message is transmitted to the MG (MGC); And (d) the MGC (MG) receiving a response confirmation message for the corresponding transaction response message from the MG (MGC), and deleting the corresponding transaction response message information from the transaction response table.

Preferably, in the above (a), when the transaction request message is not duplicated, the MGC (MG) registers the response message information for notifying the execution result of the transaction request message in the transaction response table -Recording in the response table that the current transaction is in progress with a transaction identifier in this registration process-requesting the transaction execution processing; And setting, by the MGC (MG), a maintenance timer for transmitting a transaction maintenance message to the power station if the command execution according to the transaction request message is not completed for a predetermined time.

Preferably, the method according to (c) includes transmitting a transaction maintenance message to the power and resetting the maintenance timer if the transaction is currently in progress and has not yet sent a transaction response message to the power.

Preferably, when the maintenance timer expires, (re) transmitting the corresponding transaction maintenance message, and resetting the maintenance timer.

Preferably, when a command according to the transaction request message is completed, the MGC (MG) transmits a transaction response message for notifying the MG (MGC) of the processing result, a long timer for maintaining the response message for a certain period of time Setting and waiting.

Preferably, the MGC (MG) receives a transaction response acknowledgment message for the transaction response message from the MG (MGC), and deleting the transaction response message information in the transaction response table.

Preferably, when the long timer expires, deleting the corresponding transaction response message from the transaction response table.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

3 is a block diagram showing the configuration of the ALF device of the Megaco protocol according to an embodiment of the present invention.

Referring to FIG. 3, the ALF device of the Megaco protocol in the UDP transport includes a transaction request processor 301, a transaction execution processor 302, a Megaco protocol processing processor 303, an external signal transfer processor 304, It has a logical internal structure that includes a transaction management table 305.

In the above configuration, the transaction request processor 301 is a processor that requests execution of a specific command to the power, and the transaction execution processor 302 is a processor that executes a specific command requested from the power.

In addition, the Megaco protocol processing processor 303 configures a transaction request message according to an instruction requested by the transaction request processor 301, encodes the Megaco protocol message, transmits the result to a power station, and receives a transaction request message. Send the transaction response message to the power according to the execution result.

The transaction management table 305 is connected and configured to manage a transaction request message and a transaction response message.

In particular, the transaction management table 305 is a transaction transmission table 305a for storing the transmission information of the transaction request message when the transaction request, and a transaction response table for storing the information of the transaction response message for the transaction request message when the transaction 305b.

The external signal transfer processor 304 transmits the Megaco protocol message encoded by the Megaco protocol processing processor 303 to a power station.

In addition, when requesting the execution of a transaction to the large country, the Megaco protocol processing processor 303 must manage the originating transaction request message, which includes receiving a transaction response message for the transaction request message from the large country.

In this case, i.e., when requesting a transaction to a large country, the ALF method in the transaction requester is applied.

When the external signal transfer processor 304 receives the Megaco protocol message received from the power station, the external signal transfer processor 304 transfers the received Megaco protocol message to the Megaco protocol processing processor 303, and the Megaco protocol processing processor 303 first performs parsing. If it is a transaction request message, it finds a transaction execution processor 302 to execute the command included in the transaction request, and requests to execute the command.

In addition, the Megaco protocol processing processor 303 receives a command execution result from the transaction execution processor 302 and transmits a transaction response message to the power station through the external signal transfer processor 304.

In the above process, the ALF method by the transaction performer is applied.

4 is a flowchart of an ALF method applied to a transaction requestor in the configuration of FIG. 3 according to an embodiment of the present invention.

Referring to FIG. 4, an ALF method by a transaction requester is applied to request MGC or MG to execute a specific command to a power station.

First, in MGC or MG, the Megaco protocol processing processor 303 always monitors a message received by itself (S401), and when the Megaco protocol processing processor 303 detects a new message, it determines the type of message and performs each of them. (S402).

At this time, the types of the message can be divided into five, the first is the case of receiving a transaction maintenance message from the power (S411), the second is the case of receiving a transaction response message from the power (S421), the third Is the case of receiving a transaction request message from the transaction request processor 301 (S431).

The fourth time is when the timer A, which is a retransmission timer according to the execution of the ALF method at the requestor, receives a timer A expiration message indicating that the time has expired (S431), and the fifth is how long the corresponding transaction information is maintained in the transaction transmission table. This is the case when the timer B indicating whether or not to receive the timer B expiration message indicating that the time has expired (S451).

In the above five cases, when the Megaco protocol processing processor 303 receives a transaction maintenance message from the power (S411), it is checked whether a transaction related to the transaction has been requested (S412).

At this time, to check whether the related transaction has been requested, the related transaction is identified using the transaction identifier as a key value in the transaction transfer table 305a of the transaction management table 305.

As a result of the check, if there is no transaction related to the transaction, it is regarded as an invalid message and ignored. If there is a related transaction, it is checked whether a response message of the transaction has been received (S413). After entering the procedure, the retransmission timer A is reset (S414), so that the transaction request message is not transmitted again. If the response is received, it means that the transaction maintenance message is received after receiving the transaction response, and thus the received signal is ignored.

On the other hand, when receiving a transaction response message from the power corresponding to the second message type (S411), the Megaco protocol processing processor 303 checks whether there is a transaction related to the transaction in the transaction management table (S422), and the related transaction In step S423, it is determined whether there is a response to the duplicated signal.

In step S413, the Megaco protocol processing processor 303 ignores the duplicate transaction response message and sets the response maintaining timer B and deletes the retransmission timer A if the transaction response message is not duplicated (S424).

The transaction response maintenance timer B is a timer used to delete a specific entry in the transaction transmission table 305a of the transaction management table 305. Even if a transaction has already received a transaction response, the transaction response message B may receive the same transaction response message. You can keep this information in the transaction transfer table for a period of time to ignore these duplicate transactions.

Therefore, the information is maintained until the response maintenance timer expires.

In addition, the transaction response message received in step S421 may include information on whether the counterpart country wants to confirm the transaction response.

Therefore, the Megaco protocol processing processor 303 determines whether a transaction response confirmation is required for the corresponding transaction response message (S426), and when the transaction response confirmation is required, the Megaco protocol processing processor 303 may transmit the external signal transfer processor 304. The transaction response confirmation message is transmitted to the power station through S427.

Third, when the signal received by the Megaco protocol processing processor 303 is a signal for a transaction request from the transaction request processor 301 (S431), the Megaco protocol processing processor 303 is sent by the transaction request processor 301. The command information is encoded into the Megaco protocol message corresponding to the transaction request message, and stored in the transaction transmission table 305a of the transaction management table 304, and a retransmission timer A is set (S432).

Then, the transaction request message is transmitted to the power through the external signal transfer processor 304 (S433).

The retransmission timer A is used as a criterion for determining whether to retransmit the transaction request, and the transaction transmission table 305a indicates whether the transaction request message has been retransmitted, the time of the first transmission, and whether a transaction response has been received. Indicated flags are also stored.

Fourth, if the message received by the Megaco protocol processing processor 303 is a message for expiration of the retransmission timer A (S441), the Megaco protocol processing processor 303 checks the number of retransmissions of the transaction in the transaction transmission table 305a. It is determined whether the maximum number of retransmissions has been exceeded (S442). If the maximum number of retransmissions has been exceeded, a power failure processing procedure is performed (S443).

If the maximum number of retransmissions is not exceeded, the Megaco protocol processing processor 303 retransmits the corresponding transaction request message to the power again (S443), increments the retransmission counter by '1' (S445), and resets the retransmission timer A. (S446).

The Megaco protocol processing processor 303 receiving the message indicating that the fifth message type, the response maintaining timer B has expired, deletes the corresponding entry from the transaction transmission table 305a (S452). At this time, by deleting the entry, the timer set in association with the entry is also deleted.

The setting of the retransmission timer A in the above method will be described in detail as follows.

MG has property values of normal_MG_Execution_Time, normal_MGC_Execution_Time, MG_Provisional_Response_Timer_Value, and MGC_Provisional_Response_Timer_Value.

Here, normal_MG_Execution_Time refers to the time MG expects the MGC to perform one transaction, and normal_MGC_Execution_Time refers to the time MGC expects the MG to perform one transaction.

MG_Provisional_Response_Timer_Value is a time interval in which MG expects MGC to send a transaction maintenance message, and MGC_Provisional_ Response_Timer_Value means a time interval in which MGC expects MGC to send a transaction maintenance message.

Such property values can be found through the AuditValue command of the Megaco protocol in MGC, and the property values can be set or modified through the Modify command.

These attribute values are used to set the value of the retransmission timer. The retransmission timer A is set differently when a transaction maintenance message is received and when a transaction maintenance message is not received.

If the transaction maintenance message is not received first, the value of the retransmission timeout (RTO) is calculated by Equation 1.

RTO = normal_Execution_Time + Smooth Round Trip Time (SRTT)

In Equation 1, normal_Execution_Time uses MGC or MG value according to the requestor of the transaction. SRTT reflects network delay time.

When the retransmission timer A has expired, Equation 2 is used.

RTO = normal_Execution_Time + SRTT × 2

At this time, the RTO has a limit value and is set to 4 seconds. In other words, the value of the retransmission timer A cannot be greater than 4 seconds.

In addition, the value of the retransmission timer A when receiving the transaction maintenance message is calculated by the equation (3).

RTO = min (normal_Execution_Time, Provisional_Time_Value) + SRTT × 2

Here, the limit value of the RTO is 4 seconds so that the value of the retransmission timer A does not exceed 4 seconds.

The value of the SRTT is calculated by Equation 4.

SRTT ← R

RTTVAR ← R / 2

In this case, the above equation is applied when R, which is the first round trip time (RTT), is obtained.

And, since the RTT value is obtained every 10 seconds using the ICMP message of the IP layer, SRTT is calculated according to Equation 5 when the next RTT value R 'is obtained.

RTTAVR ← (1-β) × RTTAVR + β × | SRTT-R '|

SRTT ← (1-α) × SRTT + α × R '

Where β = 1/4, α = 1/8

The timer A value is calculated as above.

In addition, the response maintenance timer B is necessary to ignore the transaction response message from the power source in duplicate and has a 'RTO x retransmission limit value'.

In this case, the retransmission limit value may be set to a value of '7' by default.

The ALF method of the transaction performer corresponding to the ALF method by the transaction requester performed as described above is as follows.

5 is a flowchart illustrating an ALF method applied to a transaction performer in the configuration of FIG. 3 according to an embodiment of the present invention.

Referring to FIG. 5, the Megaco protocol processing processor 303 in a transaction performer monitors a received message (S501), and performs a process according to the type of a received message (S502).

The types of received messages are first when receiving a transaction request message from the power (S511), second, when receiving a transaction response confirmation message from the power (S521), and the third is a transaction execution processor 302. This is the case in which the transaction response request message for transmitting the response message to the power station is completed (S531).

In addition, the fourth is a case in which an expiration message is received from a timer L (Long Timer) (S541), and the fourth is a case in which an expiration message is received from a timer P (Pending Timer) (S551).

The operation of the Megaco protocol processing processor of the transaction performer according to the above five message types is as follows.

First, when receiving a transaction request message from the power (S511), the Megaco protocol processing processor 303 checks the transaction response table 305b to determine whether the transaction has already been processed and sent a transaction response message (S512), If the transaction has already been processed, the stored transaction response message is transmitted back to the power (S513).

If the transaction is not already processed, the transaction response table 305b is examined to determine whether the transaction is in progress (S514).

If the transaction is already executed, the Megaco protocol processing processor 303 encodes the transaction maintenance message into a Megaco protocol message, transmits the result to the power station, and resets the maintenance timer P (S515).

If the transaction is not already in progress, the Megaco protocol processing processor 303 determines that a new transaction has been received, and registers the received transaction request message as a transaction in progress in the transaction response message table 305b using the transaction identifier. In operation S516, a maintenance timer P for notifying that the transaction is being processed is set.

At this time, the timer P is a timer that determines in which time interval a transaction maintenance message is sent to the power, when the transaction response message cannot be transmitted to the power in time. In other words, when the timer P expires, a transaction maintenance message is sent to the power station to inform that the current transaction is in progress, thereby preventing the power from retransmitting the transaction request.

The timer P value can be used by correcting the value of Provisional_Response_Timer_Value or normal_Execution_Time stored in MG. In this case, normal_Execution_Time and Provisional_Response_Timer_Value may have MG_Provisional_Response_Timer_Value / normal_MG_Execution_Time or MGC_Provisional_Response_Timer_Value / normal_MGC_Execution_Time depending on whether the transaction performer is MG or MGC.

In addition, the Megaco protocol processing processor 303 requests a transaction execution processor 302 capable of executing an instruction according to the transaction request to process the transaction (S517).

In addition, when receiving a transaction response confirmation from the second message type of power (S521), the Megaco protocol processing processor 303 determines whether there is a transaction related to the transaction in the transaction response table 305b (S522). If the message is ignored, it is determined whether the message is duplicated (S523).

As a result of the determination in step S523, if the transaction response confirmation message is duplicated, the Megaco protocol processing processor 303 ignores the message and if not, records the transaction response confirmation message in the transaction response table 305b. (S524).

If the third message type is a transaction response request message (S531), the Megaco protocol processing processor 303 encodes the transaction response message, finds and stores the corresponding entry in the transaction response table 305b, and associates the timer L with the corresponding transaction. After setting, the maintenance timer P set in association with the transaction is deleted (S532).

At this time, finding the transaction in the transaction response table 305b uses a transaction identifier as a key value, and the timer L determines how long the response table entry storing the transaction response is maintained in the transaction response table 305b. The default value is 30 seconds.

In addition, when receiving a message indicating the expiration of the fourth message type timer L (S541), the Megaco protocol processing processor 303 finds the transaction in the transaction response table 305b and checks whether a request has been made to confirm the transaction response. (S542), it is checked whether a transaction response confirmation message has been received from the power even if a transaction response confirmation is requested (S543).

However, if the transaction response confirmation message has not been requested for the transaction or the transaction response confirmation message has been received from the powerhouse, the Megaco protocol processing processor 303 deletes the entry from the transaction response table 305b (S545). ).

The Megaco protocol processing processor 303 receiving the expiration message of the last and fifth message type maintenance timer P (S551) transmits the transaction maintenance message to the power (S552), and transmits a transaction maintenance message to the transaction response table 305b for the transaction. Record that the response needs to be checked (S553).

Then, the maintenance timer P is reset again (S554).

As described above, in performing the ALF method from the point of view of the transaction requester and performer, the transaction management table 304 is as follows.

6 is a diagram illustrating a configuration of a transaction management table 305 according to an embodiment of the present invention.

Referring to FIG. 6, the transaction transmission table 305a and the transaction response table 305b may be divided. The transaction transmission table 305a may be divided into a transaction identifier 601 and an encoded transaction request by the ALF method described above. Message 602, retransmission count 603, transaction response reception 604, and transaction transmission time 605.

In addition, the transaction transmission table 305a includes a retransmission timer A 606 and a response maintenance timer B 607 which are set to perform ALF on the transaction requestor side.

The transaction response table 305b includes a transaction identifier 611, an encoded transaction response message 612, a state 613, whether the transaction response confirmation is required 614 and the response confirmation reception 615. It is configured to include.

In addition, as described above, the long timer L 616 and the sustain timer P 617 used by the ALF method on the transaction performer side are included.

By using the transaction management table as described above, the ALF is made between the MG or the MGC by the Megaco protocol, thereby solving problems such as packet loss and packet delay when using the Megaco protocol on a UDP transport.

As described above, the application level framing device and method of the media gateway control protocol on the UDDP transport according to the present invention proposes an ALF method for effectively coping with the packet delay or loss that may occur due to the characteristics of the UDP transport By combining the effective ALF method with the fast performance of the UDP, it is possible to exchange the Megaco protocol messages quickly and effectively between the MGC and the MG, thereby enabling a fast end-to-end VoIP (Voice over IP) service.

Claims (17)

A media gateway control protocol (hereinafter referred to as Megaco protocol) is located between media networks that are located between different networks and perform data transmission and reception by converting media to each other, and a media gate control period for providing services by controlling the media gateway. In the application level framing device used, A transaction request processor for requesting execution of any instruction to the player; A transaction execution processor that executes a command requested from the power and informs the power of the result; A Megaco processing processor that encodes a transaction message required by the transaction request processor or the transaction execution processor into a Megaco message to be transmitted to a large power, and decodes a Megaco message received from the large power; A transaction management table for storing and managing message information transmitted and received from the Megaco processing processor to a power station; And An external signal transfer processor that transmits a Megaco message from the Megaco processing processor to a power station and delivers a Megaco message received from the power to the Megaco processing processor. Megaco's application level framing device that includes. The method of claim 1, The transaction message, A transaction request message (Transaction Request) to transmit to request the execution of any command to the power; A transaction reply message for performing a command requested from the power and transmitting the result to the power; In the execution of a command requested from the power, a transaction holding message for informing that the execution of the command is not finished yet; And A transaction response acknowledgment message for informing an acknowledgment of the acknowledgment of the transaction response message transmitted from the large station to the transaction request message (Transaction ResACK) Megaco's application level framing device that includes. The method of claim 1, The transaction management table, A transaction transmission table configured to store and manage a transaction request message transmitted by the Megaco processing processor to a power station; And A transaction response table for storing and managing a transaction response message transmitted to the corresponding power station according to the execution result of the instruction execution of the transaction request message received by the megaco processing processor from the power station. Megaco's application level framing device that includes. The method of claim 3, wherein The transaction transmission table, A retransmission timer for retransmitting the transaction request message when there is no transaction response message for the transaction request message for a predetermined time; And Response maintaining timer for storing the corresponding transaction response message for a predetermined time to determine the duplicate reception of the response message for the transaction request message Megaco's application level framing device that includes. The method of claim 3, wherein The transaction transmission table, A transaction identifier according to an instruction of the transaction request message; A corresponding transaction request message encoded into the Megaco message; Information on the number of retransmissions of the transaction request message and information on whether to receive a transaction response message for the transaction request message; And Transmission time information of the transaction request message Megaco's application level framing device that includes. The method of claim 3, wherein The transaction response table, A maintenance timer for notifying the other party of a predetermined time period that the execution of the transaction request message received by the power is in progress; And Long timer for temporarily executing a transaction response message received from the power station and storing the result of the transaction response message transmitted to the power station for a predetermined time. Megaco's application level framing device that includes. The method of claim 3, wherein The transaction response table, A transaction identifier of a transaction response message for the result of performing the transaction request message received from the power station; A corresponding transaction response message encoded into the Megaco message; Information on whether a response confirmation message from the power station for the corresponding transaction response message is required; And Information on whether or not to receive a transaction response confirmation message according to whether the response confirmation message is required Megaco's application level framing device that includes. Media gateway (hereinafter referred to as MG) which is located between different networks and performs media conversion between the media to perform data transmission and reception, and a media gate controller (hereinafter referred to as MGC) that provides service by controlling the media gateway. An application level framing method applied to a transaction requestor requesting execution of a command using a gateway control protocol (hereinafter referred to as a Megaco protocol), (a) MG (MGC) encodes and transmits a transaction request message including a command for requesting execution to MGC (MG) as a Megaco protocol message, and stores the transaction request message in a transaction transmission table for transaction request message management. Then waiting for a response message from the MGC (MG); (b) the MG (MGC) receiving a response message from the MGC (MG), and determining the type of the response message; (c) determining whether a transaction response acknowledgment message is necessary when the response message is a transaction response message indicating a result of the execution of the transaction request message; And (d) if it is necessary to transmit a response acknowledgment message for the transaction response message, the MG (MGC) transmitting a response acknowledgment message for the transaction response message to the MGC (MG); Application level framing method in the transaction requestor of Megaco comprising a. The method of claim 8, In the step (a), The MG (MGC) transmits a transaction request message to the MGC (MG), and if a certain time response message is not received, the MG (MGC) retransmission timer for retransmitting the transaction request message to the MGC (MG) again. Setting an application level framing method at Megaco's transaction requester. The method of claim 8, In step (b), Determining, by the MG (MGC), whether a transaction response message is received for a predetermined time when the corresponding response message is a transaction maintenance message informing that the processing of the transaction is in progress in the power station; And If the transaction response message for the transaction is not received for a predetermined time and the retransmission timer expires, the MG (MGC) retransmits the transaction request message and resets the retransmission timer for preventing retransmission for a predetermined time. Increasing the number of retransmission information Application level framing method in the transaction requestor of Megaco comprising a. The method of claim 10, If the maximum number of retransmissions for the corresponding transaction request message is exceeded, the MG (MGC) performing a failure handling procedure for the corresponding transaction request. Media gateway (hereinafter referred to as MG) which is located between different networks and performs media conversion between the media to perform data transmission and reception, and a media gate controller (hereinafter referred to as MGC) that provides service by controlling the media gateway. In the application level framing method applied to a transaction performer receiving a command execution request using a gateway control protocol (hereinafter referred to as "Megaco"), (a) the MGC (MG) receiving a transaction request message which is an instruction processing request message from the MG (MGC), and determining whether the corresponding transaction request message has been repeatedly received; (b) If it is determined that the corresponding transaction request message has been repeatedly received, the MGC (MG) executes a command according to the corresponding transaction request message, thereby informing the MG (MGC) of the transaction response. Determining whether a message has been sent; (c) retransmitting the transaction response message to the MG (MGC) when a command according to the transaction request has already been executed and a transaction response message is transmitted to the MG (MGC); And (d) the MGC (MG) receiving a response confirmation message for the corresponding transaction response message from the MG (MGC), and deleting the corresponding transaction response message information from the transaction response table; Application level framing method in Megaco's transaction performer comprising a. The method of claim 12, According to the above (a), If the corresponding transaction request message is not duplicated, the MGC (MG) registering response message information for informing the result of the execution of the transaction request message in the transaction response table and requesting the transaction execution processing; And Setting a maintenance timer to transmit a transaction maintenance message to inform the MG (MGC) that the transaction request is in progress if the MGC (MG) does not complete an instruction according to the transaction request message for a predetermined time; Application level framing method in Megaco's transaction performer. The method of claim 12, According to the above (c), And transmitting a transaction maintenance message to the MG (MGC) and resetting a maintenance timer when an instruction according to the transaction has not yet been executed. The method of claim 13, If the retention timer expires, (re) transmitting the corresponding transaction maintenance message and resetting the maintenance timer. The method of claim 12, When the command execution according to the transaction request message is completed in the step (b), the MGC (MG) transmits a transaction response message for notifying the MG (MGC) of the processing result, and maintains the response message for a certain period of time. Setting and waiting for a long timer for the application level framing method in Megaco's transaction performer. The method of claim 16, And deleting the transaction response message from the transaction response table when the long timer expires.