JP2006186855A - Band securing and routing method in ip network - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize stable speech quality of a call, by performing band and route management using a call control signal, in a transfer system. <P>SOLUTION: In an IP telephone network which is provided with a call control system including a call control server for establishing voice communication and a transfer system including a plurality of routers, and establishes voice communication using a call control protocol and performs the voice communication, by transmitting/receiving voice data as an IP packet, one of the plurality of routers analyzes a call control signal to recognize a signal class, to secure a communication band and to perform communication routing for each call. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a bandwidth securing and route setting method for realizing stable call quality in an IP phone.

  Services have been provided that enable voice communication by establishing voice communication using a call control protocol in an IP network such as the Internet and transmitting and receiving voice data as IP packets. FIG. 1 is a schematic diagram of a conventional IP telephone system using SIP as a call control protocol, and FIG. 2 is a schematic diagram of a conventional IP telephone system using MEGACO as a call control protocol. In a conventional network, call recognition is controlled by MGC (Media Gateway Controller) / CA (Call Agent), which is a call control system, in various signaling such as MGCP / MEGACO / SIP, and a transfer system (hereinafter referred to as a call system). The content is typically described by a router) does not have a call recognition function. That is, since the router does not recognize the call, the call recognition is started by recognizing the call packet of the IP telephone (INVITE signal in the case of SIP) at the CA.

In addition, there is a method in which a router secures a band by using MPLS (Multi Protocol Label Switching) or the like and controls packet transmission. FIG. 3 is a diagram for explaining bandwidth reservation by MPLS. However, since these packet control methods perform control with reference to the IP address, label value, etc., it is possible to secure a bandwidth in units of packets, but what is a call (session) defined by the IP telephone service? It is not linked and it is impossible to control the bandwidth and route for each call (session) unit. Although the QoS control is also performed by Diffserv, it is not guaranteed but only differentiated, and QoS and bandwidth are not guaranteed even in the EF class. The IP packet is simply transferred by securing an absolutely constant bandwidth as compared with other priorities. In other words, when a packet with a 3M bandwidth used reaches a 2M bandwidth, 1M is discarded, so that the call connection is not guaranteed because a packet is discarded even during a call in progress. As for the bandwidth management method, there is a method (refer to Patent Document 1) in which a call is managed on a server like a virtual trunk (see Patent Document 1), but it is not linked to bandwidth setting in an actual transfer system. .
Japanese Patent Laid-Open No. 2003-298637 SIP textbook, IDG Japan, p. 35

  As described above, since call recognition and bandwidth control and route control need to recognize a call packet once in CA, state control for recognizing a call cannot be performed until INVITE reaches CA, For example, when a large number of calls occur, it is necessary to perform uniform packet transfer within the network up to the CA, and even a call that should secure a bandwidth must be routed in the same way as other calls. It was.

  The present invention has been made in view of such problems, and an object of the present invention is to realize stable call quality of a call by performing bandwidth and route management using a call control signal in a transfer system. An object of the present invention is to provide a bandwidth securing and route setting method in an IP network.

  In order to achieve the above object, the present invention includes a call control system including a call control server for establishing voice communication and a transfer system including a plurality of routers, and transmits and receives voice data as IP packets. In a bandwidth securing and routing method in an IP network that enables voice communication, one of a plurality of routers recognizes a signal type by analyzing a call control signal and secures a communication bandwidth for each call. A communication path is set.

  The present invention also includes a call control system including a call control server for establishing voice communication and a transfer system including a plurality of routers, and enables voice communication by transmitting and receiving voice data as IP packets. In a method for securing bandwidth and setting a route in an IP network, a communication device different from the call control server and router is provided, and the other communication device recognizes the signal type by analyzing the call control signal for each call. The communication band is secured and the communication path is set.

  In the present invention, it is preferable to separate the bandwidth of the newly requested call and the call that is already connected by analyzing the call control signal, and to secure the bandwidth independently, and by analyzing the call control signal It is preferable to separate a priority call from a general call and secure a band independently, and when a call control signal is analyzed, it is determined that the call is an emergency call or a priority call It is preferable to establish a route to a call control server for emergency calls / priority calls different from the call control server that performs normal call processing to secure a necessary bandwidth.

  In addition, the router of the present invention includes a signal analysis function for recognizing a signal type by analyzing a call control signal and securing a communication band and setting a communication path for each call.

  The present invention also includes a call control system including a call control server for establishing voice communication and a transfer system including a plurality of routers, and enables voice communication by transmitting and receiving voice data as IP packets. In the IP telephone system, one of a plurality of routers has a signal analysis function for recognizing a signal type by analyzing a call control signal and securing a communication band and setting a communication path for each call. It is characterized by providing.

  In addition, the program of the present invention establishes voice communication using a call control protocol in an IP network, and transmits a voice data as an IP packet to an IP telephone system router that enables voice communication according to the call control protocol. Based on the results of the process of receiving the signal packet, the process of analyzing the signal of the received packet, the process of recognizing the signal type by the analysis to secure the communication band and setting the communication path for each call, and And a process of transferring a packet.

  Since the present invention can perform bandwidth and path management using a call control signal by a transfer system, it is possible to control the bandwidth of a call that is already in communication and a new connection call for each signal and each call. Even when a large number of requests for connection calls occur, stable communication quality can be obtained, and user satisfaction is increased. In addition, since call control can be performed by allocating a call that is desired to be preferentially controlled such as an emergency call / priority call and a general call, stable call quality and reliable signal transfer can be realized.

  Next, embodiments of the present invention will be described with reference to the drawings. First, a presupposed network configuration will be described with reference to FIG. Here, a network configuration using SIP as a call control protocol will be described. In FIG. 4, the call control system includes a SIP server CA (SS) that is a VoIP server that performs call control in an IP telephone network for establishing voice communication, a local network, another network (PSTN network in the figure), and an ISUP. It comprises a gateway server CA (GW) for interworking signals and an address information server for routing and setting calls such as subscriber telephone numbers, IP addresses, and addresses. The transfer system includes a plurality of routers, switches, and the like that exchange packets according to IP addresses, labels, or tables. MG (Media Gateway) is a gateway device between an IP network and a PSTN line, and transmits and receives voice data as IP packets. FW is a firewall.

  The present invention is characterized in that a router in a transfer system is provided with a signal analysis function unit for recognizing a call and securing a communication band and setting a communication path. FIG. 5 is a configuration diagram illustrating the function of the router. The edge router 1 includes a signal reception function unit 11, a flow identification function unit 12, a signal analysis function unit 13, and a transfer path setting function unit 14. The signal reception function unit 11 receives the IP packet and stores it in the reception buffer, and the flow identification function unit 12 analyzes the header up to layer 3 and identifies the flow together with the port number. The signal analysis function unit 13 includes a SIP, MEGACO protocol analysis or call recognition function equivalent to a protocol, a function for recognizing a call (INVITE for SIP), a function for analyzing and identifying information that has been placed on INVITE, and the like. And a function of recognizing REGISTER, a disconnection signal, and the like. These functions in the signal reception function unit 11, the flow identification function unit 12, the signal analysis function unit 13, and the transfer path setting function unit 14 are realized by a processor in the router executing a program stored in the router. The

  FIG. 6 is a schematic diagram of the IP telephone system of the present invention when SIP is used as a call control protocol. In the case of the SIP protocol, the signal analysis function unit recognizes a standard signal standardized by RFC 3261, 2543 and the like typified by INVITE, REGISTER, and BYE, and calculates the calling number and called number from the signal in INVITE. FIG. 7 is a schematic diagram of the IP telephone system of the present invention when MEGACO is used as a call control protocol. Similarly, in the case of the MEGACO protocol, RFC3015 / H. A standard signal standardized by H.248 or the like is recognized, and the calling number and called number are similarly determined from the Notify signal. A label value of LSP (Label Switching Path) is set from the combination of the obtained calling number, called number, and signal type. From the signal analysis as described above, referring to the signal type and various parameters in the signal, the communication band is secured and the communication path is set.

The procedure for securing a specific communication band and setting a communication path is shown below.
(1) A call is made from an IP phone (a SIP or MEGACO signal is attached from a terminal at the time of making a call, or is attached by a PBX or a relay device on the way).

(2) When the IP packet reaches the edge router, the signal analysis function unit of the router recognizes the call control signal type by analyzing the call control signal, and recognizes that the packet is a call signal.

(3) After recognizing the call signal, the signal analysis function unit of the router checks the call number and the call number in the call signal by collating with the call number analysis database registered in advance in the signal analysis function unit. Is determined. Based on the transmission number and the incoming number obtained as a result of the analysis, the IP address information and subscriber information are determined, and the LSP used for routing is determined from the preset LSP. The determined LSP is set as a label value of the LSP in the IP packet of the calling signal analyzed using FEC MAP (Forward Error Correction MAP).

(4) The LSP that is set by the FEC MAP setting performed in (3) is a static LSP that is set in advance between the ER-CA accommodating routers, or a new RSVP-TE (RSVP Traffic Engineering), LDP ( Whether the LSP is set using a Label Distribution Protocol) or the like may be used.

(5) There are the following three setting methods for setting the mapping between the label and the LSP.

Setting method (part 1): Band / route setting for each signal Separate the band of the newly requested call such as INVITE and REGISTER and the band of the already connected call, and secure the band independently by the procedures (1) to (4) above. This ensures stable voice quality and reliable exchange of control signals. Specifically, the control signal and the voice packet band to be secured other than the INVITE and REGISTER signals are separated, and the signal is analyzed. As a result, the FEC MAP is set so that the IP packet flows in the band of each signal. Set. FIG. 8 is a diagram illustrating an example of band setting for each signal in the case of SIP. As shown in FIG. 8, by recognizing a call, for INVITE and REGISTER, a fixed band is set for one LSP for a plurality of calls, and for other signals, the LSP is set or increased for each call, as shown in FIG. Ensure signal transmission / reception by bandwidth setting. When this method is used, even if a large number of INVITE and REGISTER new connection request calls occur, it is possible to prevent the control signals and voice packets that are already connected from being affected. FIG. 9 is a diagram illustrating an example of band setting for each signal in the case of MEGACO. As shown in FIG. 9, by notifying the call, Notify is set to a fixed band with one LSP for a plurality of calls, and other signals are subjected to LSP setting or band increase for each call to set the band as shown in the figure. Ensure signal transmission / reception.

Setting method (No. 2): Band type / route setting of call types such as priority call and general call Analyzing the INVITE signal, separating the call to be prioritized (110/119 etc.) from the general call, By securing the bandwidth by the procedures 1) to (4), stable voice quality and reliable exchange of control signals are realized. Specifically, the signal is analyzed, the called number and the calling number in the INVITE signal are analyzed, and it is determined whether it is general or preferred. If priority is given, a priority LSP and a general LSP can be used. However, if there is an unused LSP in the general LSP (using the general LSP), a general LSP can be used. If a general new request call that is connected after that is connected, a priority call can be stably connected by performing a routing setting that does not connect. FIG. 10 is a diagram illustrating a bandwidth setting example of call types such as a priority call and a general call. As shown in FIG. 10, by recognizing a call, an LSP is set for the call type, and signal transmission / reception by band setting as shown in the figure is ensured.

Setting method (No. 3): Band / route setting when installing CA for emergency / priority calls When the destination is found to be 110/119 as a result of signal analysis according to the procedures (1) to (4) above Then, the routing to the LSP routed to the emergency call / priority call CA different from the CA that performs the normal call processing is set, and the band necessary for passing the call control signal is secured. FIG. 11 is a diagram illustrating an example of bandwidth setting when a CA for emergency / priority calls is installed. By recognizing the call, band setting is performed for CA1 (SS) for priority call / emergency call and CA2 (SS) for general call as shown in the figure to ensure signal transmission / reception.

  A band / route setting method considering only one of the above three setting methods may be used, or a band / route setting method combining two or more may be used.

  Note that the bandwidth reservation itself may be a bandwidth set by signaling, such as RSVP-TE or LDP, or a bandwidth set in cooperation with a QoS server. In the above-described embodiment, the case of securing the bandwidth using the LSP has been described. However, means by securing resources such as RSVP may be used.

  In the above-described embodiment, the call control signal band securing has been described. However, it is also possible to simultaneously secure the band necessary for passing a voice signal simultaneously from the IP address of arrival and departure obtained as a result of the analysis. Alternatively, it may be possible to ensure only the bandwidth that allows the audio signal to pass individually.

  In addition, the router is determined to be in a congestion state from the device state / line usage state of the router itself, or when the congestion is notified from a related system such as CA / MG / FW by other methods, the LSP bandwidth that is initially set is exceeded. When a call is congested, it is possible to cancel the transmission of a general call having a low priority setting.

(6) With the above, transfer to CA (SS) via core router 2 using LSP with FEC MAP setting, detailed signal analysis and service analysis at CA (SS), IP address set, predetermined Send a packet to the destination.

(7) The router analyzes the IP address and call control signal set in CA (SS) in the same procedure as in (3), and the LSP from the CA (SS) to the router in which the called terminal is accommodated. Set FEC MAP and set bandwidth.

(8) The packet is transferred to the destination router by the set LSP, and a call connection request is made to the destination terminal.

(9) After receiving the signal, the receiving terminal starts transmission / reception of the U-plane signal, transmits a ringing tone, and receives the signal at the calling side.

(10) Lower the handset and terminate the call connection at CA. Release the bandwidth that was set when the call connection ended.
This completes the call.

  In the above-described embodiment, the signal analysis function unit is provided in the router so that the router recognizes the call and secures the communication band and sets the communication path. However, it is different from the call control server, router, and switch. Another communication device may be provided with a signal analysis function unit so that a call is recognized by another communication device and a communication band is secured and a communication path is set.

1 is a schematic diagram of a conventional IP telephone system using SIP as a call control protocol. 1 is a schematic diagram of a conventional IP telephone system using MEGACO as a call control protocol. FIG. It is a figure explaining the band reservation by MPLS. It is a figure explaining the network structure used as a premise. It is a block diagram explaining the function of an edge router. It is the schematic of the IP telephone system of this invention in the case of using SIP as a call control protocol. It is the schematic of the IP telephone system of this invention at the time of using MEGACO as a call control protocol. It is a figure which shows the example of a zone | band setting according to the signal in the case of SIP. It is a figure which shows the band setting example according to signal in the case of MEGACO. It is a figure which shows the example of a band setting of call classifications, such as a priority call and a general call. It is a figure which shows the example of a zone | band setting in the case of installing CA for emergency call / priority call.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Edge router 2 Core router 11 Signal reception function part 12 Flow identification function part 13 Signal analysis function part 14 Forwarding path setting function part

Claims (8)

Securing bandwidth in an IP network that includes a call control system including a call control server for establishing voice communication and a transfer system including a plurality of routers and enables voice communication by transmitting and receiving voice data as IP packets And in the route setting method,
Bandwidth reservation and route setting in an IP network, wherein a router of the plurality of routers recognizes a signal type by analyzing a call control signal and performs communication bandwidth reservation and communication route setting for each call. Method. Securing bandwidth in an IP network that includes a call control system including a call control server for establishing voice communication and a transfer system including a plurality of routers and enables voice communication by transmitting and receiving voice data as IP packets And in the route setting method,
Provided with another communication device different from the call control server and router, the other communication device recognizes the signal type by analyzing the call control signal, and secures the communication band and sets the communication path for each call. A bandwidth reservation and route setting method in an IP network.   The bandwidth reservation in the IP network according to claim 1 or 2, wherein the bandwidth of the newly requested call and the already connected call is separated by analyzing the call control signal, and the bandwidth is secured independently of each other. And routing method.   3. The bandwidth reservation and route setting in the IP network according to claim 1 or 2, wherein the call control signal is analyzed to separate a priority call and a general call and secure a bandwidth independently of each other. Method.   If the call control signal is analyzed and it is determined that the call is an emergency call or a call to be prioritized, a call for emergency call / priority call different from the call control server performing normal call processing 3. The bandwidth securing and route setting method in the IP network according to claim 1, wherein a route is set to the control server and a necessary bandwidth is secured.   A router comprising a signal analysis function for recognizing a signal type by analyzing a call control signal and securing a communication band and setting a communication path for each call. In an IP telephone system including a call control system including a call control server for establishing voice communication and a transfer system including a plurality of routers, and enabling voice communication by transmitting and receiving voice data as IP packets,
One router of the plurality of routers has a signal analysis function for recognizing a signal type by analyzing a call control signal and securing a communication band and setting a communication path for each call, IP phone system. In a router of an IP telephone system that enables voice communication by establishing voice communication using a call control protocol in an IP network and transmitting / receiving voice data as an IP packet,
Receiving a packet of signals according to a call control protocol;
Processing to analyze the signal of the received packet;
Processing for recognizing the signal type by the analysis and securing the communication band and setting the communication path for each call;
Processing to forward the packet based on the result of the analysis;
A program characterized by having executed.

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