JP2005073106A - QoS CONTROL SYSTEM AND QoS CONTROL METHOD - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high quality communication service of a resource securing type by a session control on an IP network making delay concerning scalable and resource securing minimum. <P>SOLUTION: A session controller 11 receives a session establishment request message from a user terminal 3 and a session establishment answer message from a user terminal 4, and notifies address information and secured resource information of the user terminal 3 and the user terminal 4 to a resource management part 12. The resource management part 12 discriminates whether resource reservation is possible or not based on the noticed information, and notifies the discrimination result to the session controller 11. The session controller 11 performs establishment or disconnection of the session based on the discrimination result. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a QoS control method for securing a network resource, and in a communication application for performing session control by SIP (Session Initiation Protocol) on an IP network, such as VoIP, video and voice communication, a TV conference system, and video distribution. (Quality of Service) It belongs to the technical field related to provision.

  As high-speed and broadband applications become widespread on the Internet, services that provide QoS over IP networks have become important. On the other hand, in communication applications that perform session control using SIP or the like, it has become necessary to establish a session after reserving network resources.

  However, in the conventional session control, there is no network resource securing method before the session is established, and the QoS is provided because the network resource is not secured after the session is established after a ringing response or the like. I could not.

  In order to prevent the establishment of a session in which network resources are not secured in response to this problem, in the case of a SIP session, communicators negotiate network resource requirements before Ringing in RFC 3312 (see Non-Patent Document 1). A method has been proposed in which a resource is reserved using network resource reservation means such as RSVP (Resource reSerVation Protocol), and then Ringing is performed to establish a session in which QoS is ensured.

  However, when RSVP exemplified as network resource reservation means in this RFC is used (see, for example, Non-Patent Document 2), it is necessary to install an RSVP-compatible network device in the network, and resources are provided by signaling at the time of resource reservation. Since the time required for scalability and the resource reservation for the network scale depends on the performance of the network device and the number of devices, there may be a problem in terms of response time.

  FIG. 9 shows a sequence of a method using RSVP as a resource reservation method exemplified in the conventional RFC3312. Here, a case where a session is started between the user terminal 3 and the user terminal 4 will be described as an example.

  In order to make a session establishment request, the user terminal 3 transmits SDP1 to the user terminal 4 by an INVITE message that is a SIP message (S7-1). The user terminal 4 transmits SDP2 to the user terminal 3 by the 183 response (S7-2). The user terminal 3 transmits a PRACK message to the user terminal 4 (S7-3), and the user terminal 4 makes a 200 OK response to the PRACK message (S7-4).

  Next, the user terminal 3 transmits RSVP PATH to the user terminal 4 (S7-5), and the user terminal 4 transmits RSVP RESV to the user terminal 3 (S7-6). In addition, the user terminal 4 transmits RSVP PATH to the user terminal 3 (S7-7), and the user terminal 3 transmits RSVP RESV to the user terminal 4 (S7-8). Resource reservation by RSVP is performed by the processing of S7-5 to S7-8.

  Next, the user terminal 3 transmits an UPDATE message to the user terminal 4 (S7-9), and the user terminal 4 transmits 200 OK (UPDATE) to the user terminal 3 (S7-10). Subsequently, the user terminal 4 performs 180 Ringing (S7-11). The user terminal 3 transmits a PRACK message for this (S7-12), and the user terminal 4 returns 200 OK for the PRACK message (S7-13).

  Next, the user terminal 4 returns 200 OK for the first INVITE message (S7-14), and the user terminal 3 returns ACK (S7-15). Thereby, a session is started (S7-16).

Non-Patent Document 3 below describes a resource management function for centrally managing bandwidth for each link of a network.
G. Camarillo, et al., "Integration of Resource Management and Session Initiation Protocol (SIP)", RFC3312, IETF, Oct. 2003. S. Sargento, et al., "IP-Based Access Networks for Broadband Multimedia Services", IEEE Communication magazine, pp.146-154, Feb. 2003. Yaguchi et al., "A Proposal and Specific Example of Resource Management Method Using Management Server in Large IP Network", IEICE General Conference, B-6-31, Mar.2002.

  In session control using SIP using conventional IP technology, resources necessary for communication are secured in order to make a call (Ringing) to the communication partner before reserving network resources. In some cases, high-quality communication quality could not be ensured.

  Further, when the conventional method using RSVP as the resource reservation means as shown in FIG. 9 is used, in order to perform resource reservation (S7-5 to S7-8) by RSVP, an RSVP-compatible network device is connected to the IP network. Furthermore, since the time required for resource reservation depends on the performance of the RSVP-compatible network device and the number of devices, there is a possibility that the time for securing the resource may be a problem.

  An object of the present invention is to solve the above-described problems and provide a resource securing type high quality communication service by session control on an IP network in a scalable manner with a minimum delay in securing resources.

  In order to solve the above problems, the present invention realizes scalable and delay-free resource reservation by using a resource management function (for example, see Non-Patent Document 3) that centrally manages bandwidth for each link of a network. On the other hand, a service that provides QoS can be realized by a network resource reservation type session control method in which Ringing is not performed until resource reservation is completed. That is, in response to the above-described problem that a session establishment in which network resources are secured can be realized in a scalable manner without delay with respect to resource securing time, the present invention provides a session control means described below as a resource reservation method in a resource securing session establishment procedure And resource management means.

  In the present invention, the communication control terminals negotiate both resource request conditions, and at the same time, the session control means for relaying the terminals sends a message relating to the resource request specified by the session control protocol to the resource management means. Resource reservation is performed by using and notifying.

  The resource management means performs bandwidth determination and network resource information update by comparing the requested bandwidth with network resource information that is managed by the resource management means. Since the resource management means centrally manages the available bandwidth in each link of the network using a database (DB) or the like, the search time for the resource request is short. This determination result is notified to the session control means, and the network resource is secured by changing the message content related to the resource request and notifying the terminal based on the determination result in the session control means.

  If network resources are secured, Ringing and subsequent sessions that secure the network resources are established and communication is started. At this time, when it is necessary to control the traffic flow of the IP packet transmitted from the communication terminal, the initial session establishment request message is transmitted with an identifier related to the necessity of traffic flow control. After the ringing after the network source is reserved in the resource management unit, the ToS (Type of Service) value of the IP header is sent from the resource management means to the device or edge device installed in the home where the communication terminal is installed. The traffic flow is determined after the resource is secured by changing the priority packet flag, by means of notifying and controlling the traffic flow control means to operate, and resource reservation by the resource management means in two steps. Control. By securing resources in two stages in this way, it is possible to reduce the delay time from the first INVITE resource request to Ringing compared to when traffic flow control is performed simultaneously with network resource reservation by the resource management means. Become.

  When the communication between the communication terminals is completed, the session control means receives the session control signal related to session termination and notifies the resource management means, thereby releasing the bandwidth related to the session in the resource management means, and the network resource information Updated.

  If the bandwidth is not reserved by the resource management means due to a shortage of network resources, the session request is interrupted, and Ringing is not performed for a session that does not secure the resource, and a response that the resource is not secured is not performed.

  Furthermore, according to the present invention, in order to distinguish between a session that does not require resource reservation and a session that requires resource reservation, an identifier relating to the necessity of resource reservation is attached to the first session establishment request message. Based on this identifier, the session control means can process the session that does not require resource reservation, by not notifying the resource management means, so that it can be distinguished from the session that secures the resource.

  According to the present invention, when network resources are secured and communication is performed using a session control method such as SIP, Ringing is not performed in a state where resources are not secured, and resource reservation using RSVP of network resources is performed. It becomes possible to apply a resource securing type communication service that is more scalable than a system and can be secured in a short time.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a configuration example of the present invention. This figure shows a mode in which user terminal devices communicate with each other following establishment of a session by SIP.

  The embodiment of the present invention shown in FIG. 1 includes a QoS control system 1 for controlling QoS, an IP network composed of a core network device 20, an edge network device 21, a user premises device 22, and the like, and a user terminal for communication. It is composed of 3 and 4.

  The QoS control system 1 includes a session control unit 11 having a session control function, and a resource management unit 12 having a resource management function for centrally managing the used bandwidth of an IP packet flowing on an IP network for each link. . The resource management unit 12 has a resource management DB 13 in which usable bandwidth information in each link of the network is stored.

  The session control unit 11 is realized by one or a plurality of workstations, a server device, a PC server, a computer such as a PC, and a software program. The resource management unit 12 is also realized by a computer such as one or a plurality of workstations, a server device, a PC server, and a PC, and a software program. The session control unit 11 and the resource management unit 12 can be implemented in separate housings or in the same housing.

  When the user terminal 3 communicates with the user terminal 4 while securing resources on the IP network, the user terminal 3 sends a terminal identifier such as its own terminal IP address to the session control unit 11 of the QoS control system 1, and The user who wants to communicate by describing the bandwidth required for communication, the identifier for requesting a session that secures resources, the identifier for necessity of traffic flow control, etc. as the SDP of the INVITE message that is a SIP message. The terminal 4 is designated by a SIP address or the like, and a communication start request is transmitted to the session control unit 11 (S1-1).

  At this time, the session control unit 11 transfers an INVITE request to the user terminal 4 (S1-2). At this time, the contents of the SDP from the user terminal 3 are referred to and it is confirmed that the request is a resource reservation type session request and the user requests resource reservation type communication.

  The user terminal 4 confirms from the SDP content of the INVITE message that the user terminal 3 is requesting resource securing type communication, and if the communication is permitted, describes the resource securing request in the direction of the user terminal 3 in the SDP. Then, it is transmitted as a 183 response to the session control unit 11 (S1-3).

  The session control unit 11 refers to the resource reservation request in the user terminal 4 direction included in the INVITE message from the user terminal 3 and the resource reservation request in the user terminal 3 direction included in the 183 response. The address and bidirectional requested bandwidth are transmitted to the resource management unit 12 (S1-4).

  The resource management unit 12 calculates a passage route based on the IP network topology table possessed from the IP address, and accumulates necessary bandwidth for each passing link. If the accumulated result does not exceed the maximum resource amount for each link, resource reservation is notified to the session control unit 11, and if not, resource reservation impossibility is notified (S1-5).

  The session control unit 11 rewrites the SDP of the 183 response to the user terminal 3 and, when resource reservation is performed, indicates that the resource reservation has been performed using a current value defined by RFC3312. Notification is made (S1-6). If not, the fact that the resource reservation has failed is notified by returning an error message or the like.

  Next, a precondition for a resource request between the user terminals 3 and 4 is determined by signaling between terminals shown in FIG. 2 to be described later based on RFC 3312. In an application that performs Ringing, Ringing is performed, and the user terminal 3 , 4 establish a session. The above procedure is collectively shown as procedure S1-7 in FIG.

  When performing traffic flow control, when the session control unit 11 receives a 200 OK message (S1-8) from the user terminal 4 for the first INVITE, the session control unit 11 controls the traffic flow control to the resource management unit 12. (S1-9), the resource management unit 12 sends a priority packet such as a ToS (Type of Service) value in the IP header to the user home device 22 or the edge network device 21 in which the communication terminal is installed. The flag is changed, and a notification is made to activate traffic flow control means such as traffic shaping or policing (S1-10). After the operation completion notification (S1-11) from the control target device such as the user home device 22 and the edge network device 21 to the resource management unit 12 and the operation completion notification (S1-12) from the resource management unit 12 to the session control unit 11, the session A 200 OK message is transferred from the control unit 11 to the user terminal 3 (S1-13). Thereafter, communication in which network resources are secured is started between the user terminals 3 and 4 (S1-14).

  FIG. 2 is a sequence diagram at the start of a session in the embodiment of the present invention. The flow of processing will be described with reference to this figure. The user terminal 3 transmits an INVITE message to make a session establishment request (S2-1). At this time, the description of securing the resource of the SDP (SDP1) in the INVITE message is as shown in FIG. Hereinafter, a setting example of the SDP1 information shown in FIG. 3A will be described in accordance with the notation described in RFC3312.

  In the case of this example, the quality ensuring section is an end-to-end section from the user terminal 3 to the user terminal 4 and quality is not ensured (none). Furthermore, quality reservation is requested in both end-end (e2e) direction (sendrecv). The necessary bandwidth is X, and the identifier that is a resource reservation request is Z.

  The session control unit 11 checks the above information and, if the identifier contains Z, transfers the INVITE message to the user terminal 4 (S2-2). Further, the user terminal 4 confirms the INVITE message, and transmits SDP (SDP3) to the session control unit 11 as a 183 response (S2-3). The session control unit 11 transmits the IP addresses (A, B) and bidirectional requested bandwidths of the user terminals 3 and 4 acquired from the SDP1 and SDP3 to the resource management unit 12 (S2-4).

  The resource management unit 12 searches the resource management DB 13 based on this information and returns a resource determination result (bandwidth determination result) to the session control unit 11 (S2-5). In the session control unit 11, when it is determined that the network resource is reserved by the resource management unit 12, the current value of the SDP is changed from no resource reservation (none) to the direction in which the resource is reserved (in this example, sendrecv indicating bidirectional). ) And transmitted to the user terminal 3 (S2-6).

  An example of the rewritten SDP information (SDP4) is shown in FIG. When receiving this message, the user terminal 3 transmits a PRACK message to the user terminal 4 (S2-7, S2-8). In response to this, the user terminal 4 makes a 200 OK response to the PRACK message (S2-9, S2-10).

  Next, the user terminal 3 transmits an UPDATE message to the user terminal 4 (S2-11, S2-12), and the user terminal 4 refers to the SDP (SDP6) in the UPDATE message and holds it in the user terminal 4. The contents of SDP2 are synchronized and 200OK (UPDATE) is transmitted to user 3 (S2-13, S2-14). Subsequently, the user terminal 4 performs 180 Ringing (S2-15, S2-16).

  The user terminal 3 transmits a PRACK message for this (S2-17, S2-18), and the user terminal 4 returns 200 OK for the PRACK message (S2-19, S2-20). Subsequently, 200OK for the first INVITE message is returned (S2-21, S2-22), and ACK is returned from the user terminal 3 (S2-23, S2-24). Thereby, a session is started in a state where network resources are secured (S2-25).

  FIG. 4 is a diagram illustrating a case where traffic flow control is performed in the sequence according to the embodiment of the present invention. Regarding the description of securing the SDP resource in the INVITE message, it is assumed that the quality reservation section and the quality reservation direction are the same as those in FIG. Assuming that Y is an identifier that is a resource reservation request for performing traffic flow control, FIG. 5A shows an example of identification for traffic flow control by setting information of SDP1. In the flow of processing according to this figure, steps S8-1 to S8-21 are the same as steps S2-1 to S2-21 in FIG. A setting example of SDP2 is shown in FIG.

  When the session control unit 11 receives a 200 OK message for INVITE from the user terminal 4 in S8-21, the session control unit 11 stores that this session is a traffic flow control target from the time when the first INVITE is received. Therefore, the resource management unit 12 is notified to control the traffic flow (S8-22). In response to this, the resource management unit 12 sends a priority packet flag such as a ToS (Type of Service) value in the IP header to a device that controls traffic flow such as a device installed in a home where a communication terminal is installed or an edge device. And notifies the user to activate the traffic flow control means (S8-23). Upon receiving the notification that the operation has been completed (S8-24), the resource management unit 12 notifies the session control unit 11 of the operation completion (S8-25), and the session control unit 11 sends 200 OK to the user terminal 3. The message is transferred (S8-26). Next, an ACK from the user terminal 3 is received by the user terminal 4 (S8-27, S8-28), whereby a session is started in a state where network resources are secured (S8-29).

  FIG. 6 is a sequence diagram at the end of the session. At the end of the session, with a BYE request (S4-1) from one of the user terminals, the session control unit 11 notifies the resource management unit 12 of resource release (S4-2), and the resource management unit 12 When the resource reserved for the session is released and traffic flow control is performed, the setting of the network device to be controlled is canceled (S4-3), and the session control unit indicates that these have been completed. 11 (S4-4), and the session control unit 11 transfers BYE (S4-5). The user terminal 3 that has received BYE transmits 200 OK to the user terminal 4 that has transmitted BYE (S4-6, S4-7), and ends the session.

  7 and 8 show an example of a flowchart of the resource securing type session according to the present invention. FIG. 7 is a diagram showing a processing flow at the start of a session. In response to the session request (S5-1) from the user terminal 3, the session control unit 11 checks the SDP in the INVITE message (S5-2), determines whether or not the user is a session establishment target user (S5-3), and It is determined whether or not resources need to be secured and whether or not there is traffic flow control (S5-4).

  If the user is not a session establishment target user, an error message is sent to the user terminal 3 (S5-23), and the process ends. If the user is a session establishment target but is not a resource reservation type request, the INVITE message is transferred to the user terminal 4 (S5-24), and 200OK (INVITE) is transmitted from the user terminal 4 to the user terminal 3 (S5). -25), a resource non-secure session is started (S5-26).

  If the user is a session establishment target user and the resource reservation type request requires resource reservation, the INVITE message is transferred to the user terminal 4 (S5-5). The user terminal 4 returns a 183 response to the transferred INVITE message after confirming the SDP (S5-6). The session control unit 11 notifies the resource management unit 12 of information necessary for resource determination among the SDP information such as the IP address and bandwidth information in the 183 response (S5-7). Based on the above, band determination is performed (S5-8).

  When the bandwidth determination result is NG and the resource reservation cannot be made (S5-9), the resource management unit 12 notifies the session control unit 11 to that effect, and the session control unit 11 sends an error message to the user terminal 3. It returns (S5-27) and the session ends. If the bandwidth determination result is OK and resource reservation is possible, the session control unit 11 rewrites the SDP in the 183 response and transmits it to the user terminal 3 (S5-10).

  The user terminal 3 transmits a PRACK message to the user terminal 4, and the user terminal 4 returns 200OK for this (S5-11). The user terminal 3 transmits an UPDATE message requesting the user terminal 4 to update the SDP information, and the user terminal 4 returns 200 OK (UPDATE) (S5-12). By this process, Precondition is established. Further, 180 Ringing is transmitted from the user terminal 4 (S5-13).

  Next, the user terminal 3 transmits a PRACK message to the user terminal 4, and the user terminal 4 returns 200 OK (S5-14). Then, the user terminal 4 returns 200OK for the first INVITE message for establishing the session (S5-15). On the other hand, if the traffic flow control is unnecessary, the session control unit 11 sends 200OK to the user terminal 3. (S5-20), the user terminal 3 transmits ACK to the user terminal 4, the user terminal 4 receives it (S5-21), and a session is started in a state where network resources are secured (S5-21). S5-22).

  When traffic flow control is necessary (S5-16), the session control unit 11 notifies the resource management unit 12 that traffic flow control is to be performed (S5-17), and the traffic flow control is performed from the resource management unit 12. A control message is notified to the network device to be controlled (S5-18). When the operation for traffic flow control is completed, the session control unit 11 receives a notification to that effect via the resource management unit 12 (S5-19), and transfers 200OK to the user terminal 3 (S5-20). Next, an ACK from the user terminal 3 is received by the user terminal 4 (S5-21), and a session is established (S5-22). As a result, the session is started with network resources secured.

  The procedure (S6-1 to S6-7) shown in FIG. 8 is a flowchart example at the end of the session. In this flowchart, when the session ends, when the BYE request (S6-1, S6-2) from the user terminal 4 is received by the session control unit 11, the session control unit 11 manages resource (bandwidth) release. Request to the unit 12 (S6-3). When the resource management unit 12 releases the resource (bandwidth) reserved for the session and performs traffic flow control, the setting of the network device to be controlled is canceled and the fact that these have been completed. Is notified to the session control unit 11 (S6-4), and the session control unit 11 transfers BYE to the user terminal 3 (S6-5). The user terminal 3 sends 200 OK to the user terminal 4 (S6-6), and ends the session (S6-7).

It is a figure which shows the structural example of this invention. It is a sequence diagram at the time of session start. It is a figure which shows the example of a setting of SDP information. It is a sequence diagram at the time of the session start in the case of performing traffic flow control. It is a figure which shows the example of a setting of SDP information in the case of performing traffic flow control. It is a sequence diagram at the time of session termination. It is a figure which shows the processing flow at the time of a session start. It is a figure which shows the processing flow at the time of session end. It is a figure which shows the conventional session establishment system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 QoS control system 2 IP network 3, 4 User terminal 11 Session control part 12 Resource management part 13 Resource management DB
20 Core network device 21 Edge network device 22 User premises device

Claims (6)

A QoS control system for securing network resources before establishing a session between communication terminals connected via a network,
Session control means for controlling a session between the communication terminals;
Resource management means for centrally managing network resources for each network link on the network,
The session control means includes:
Receiving the session establishment request message from the first communication terminal and the session establishment response message from the second communication terminal among the communication terminals, and the addresses of the first communication terminal and the second communication terminal Processing means for notifying the resource management means of information and network resource information to be secured,
The resource management means includes:
Processing means for determining whether or not network resource reservation is possible based on the information notified from the session control means, and notifying the determination result to the session control means;
The session control means further includes:
If the determination result notified from the resource management means is that network resource reservation is possible, the first communication terminal is notified that network resource reservation has been performed, and a session is established, and the determination If the result is that network resource reservation is not possible, the QoS control is characterized by notifying the first communication terminal that network resource reservation has not been made, and having a processing means for interrupting session establishment system. The QoS control system according to claim 1,
The session control means includes:
In the received session establishment request message, identification information indicating whether or not to request a session that secures network resources is identified, and whether or not a session that requires securing of network resources is requested before session establishment is determined. Processing means to determine;
When it is determined that a session that requires securing of network resources is requested, the resource management means is notified of the address information of the first communication terminal and the second communication terminal and the network resource information to be secured. A processing means for establishing a session only when resource reservation is possible, and interrupting session establishment when network reservation is impossible;
A QoS control system comprising: processing means for establishing a session when it is determined that a session that does not require securing network resources before establishing the session is requested. The QoS control system according to claim 1,
The session control means includes:
Means for identifying whether or not communication traffic flow control transmitted from a communication terminal is necessary,
The resource management means includes:
Means for notifying the network device or edge device installed in the home where the communication terminal is installed, that the communication traffic flow from the communication terminal is controlled by the notification from the session control means;
In the network device or the edge device installed in the home, the priority packet flag is changed by the notification from the resource management unit, and the traffic flow control unit is operated to match the network resource reservation by the resource management unit. A QoS control system characterized by securing network resources in two stages. A QoS control method in a communication system comprising session control means for controlling a session between communication terminals connected via a network and resource management means for centrally managing network resources for each network link,
The session control means receives a session establishment request message from a first communication terminal and a session establishment response message from a second communication terminal among the communication terminals, and receives the first communication terminal and the first communication terminal. Notifying the resource management means of the address information of the two communication terminals and the network resource information to be secured;
The resource management means determining whether network resource reservation is possible based on the information notified from the session control means, and notifying the session control means of the determination result;
If the determination result notified from the resource management means is that network resource reservation is possible, the session control means notifies the first communication terminal that network resource reservation has been made, and And when the determination result indicates that network resource reservation is not possible, the first communication terminal is notified that network resource reservation has not been performed, and the session establishment is interrupted. The QoS control method characterized by these. The QoS control method according to claim 4,
In the received session establishment request message, the session control means identifies identification information indicating whether or not to request a session that secures network resources, and there is a session that needs to secure network resources before session establishment. Determining whether requested, and
When the session control means determines that a session that requires securing of network resources is requested, the resource management includes address information of the first communication terminal and the second communication terminal and network resource information to be secured. Informing the means and establishing the session only when the network resource reservation is possible, and interrupting the session establishment when the network reservation is impossible;
A QoS control method, comprising: a step of establishing a session when it is determined that a session that does not require securing of network resources before the session is established is requested. The QoS control method according to claim 4,
The session control means identifying the necessity of communication traffic flow control transmitted from a communication terminal;
The resource management means notifying the network device or edge device installed in the home where the communication terminal is installed that the communication traffic flow from the communication terminal is controlled by the notification from the session control means; ,
In the network device or the edge device installed in the home, the priority packet flag is changed by the notification from the resource management unit, and the traffic flow control unit is operated to match the network resource reservation by the resource management unit. A QoS control method comprising: securing network resources in two stages.

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