KR100789630B1 - Method of managing resource for ensuring service of qulity between host in ip network, session establishing method using the same, and system thereof - Google Patents

Abstract

The present invention uses the integrated service for the small access network and the differential service for the transmission network, and in the session establishment between the non-client side and the destination host end in each access network, the session is established after the quality of service required by the user is provided. In order to ensure that, when the originating SIP server requests the policy related to the quality of service according to the session initiation request of the originating host, a first step of transmitting the session performance acceptance result according to the quality of service policy management rule to the originating SIP server; A second step of, when the called SIP server requests a quality of service policy according to a request for initiating a session of the called host, transmitting a session performance acceptance result according to a quality of service policy management rule to the called SIP server; And an RTP session between the originating SIP server and the terminating SIP server is established only when the session execution with respect to the originating SIP server is accepted and the session execution with respect to the terminating SIP server is accepted.

Description

Resource management method to guarantee service quality between host end-to-end, session establishment method and system using it {METHOD OF MANAGING RESOURCE FOR ENSURING SERVICE OF QULITY BETWEEN HOST IN IP Network

1 is a block diagram of an Internet network to which a conventional session initiation protocol is applied.

2 is a message flow diagram illustrating a session initiation procedure using a SIP protocol in a conventional Internet network.

3 is a message flow diagram illustrating a session initiation procedure using a resource reservation protocol in a conventional Internet network.

4 is a block diagram of an internet network to which the present invention is applied.

5 to 8 are message flow diagrams illustrating a session establishment method using a resource management method for guaranteeing a service quality between host ends according to an embodiment of the present invention.

The present invention relates to a resource management method for guaranteeing service quality between hosts, a session establishment method, and a system using the same. More specifically, an integrated service is used for a small access network and a differential service is used for a transport network. In the session establishment between the sender side and the destination host end belonging to, the present invention relates to a technique for allowing a session to be established after the quality of service required by the user is provided.

In general, session establishment using the session initiation protocol in the Internet network is logically made up of a plurality of hosts (computers) 11 and 12 and SIP servers 13 and 14 performing sessions, as shown in FIG. It takes place between the Internet Protocol (IP) networks. The SIP servers 13 and 14 perform a function of mediating the client's response corresponding to the client's request on behalf of the client (host), and adding address translation and simultaneous transmission to multiple clients according to the client's request. It also performs a functional function. The logical IP network consists of various physical routers (R1, R2, R3, R4, ..., Rn).

FIG. 2 is a message flow diagram illustrating a general procedure of initiating a session between two hosts using a SIP server in an access network to which each host of a calling party and a called party belongs in the Internet network configuration shown in FIG. 1.

For convenience, it is assumed that the host A 11 in the access network A is the originating host and the host B 12 in the access network B is the called host.

First, the host A 11 transmits a session request message INVITE to the SIP server 13 to initiate a session with the host B 12 (S201). Then, the calling SIP server (one side forwards the session request message (INVITE) to the called SIP server 14 (S202), and the called SIP server 14 sends the session request message (INVITE) to the host B 12. In operation S203, when the host B 12 transmits an incoming response message 200OK indicating that the host B 12 has received the session request message to the SIP server 14 (S204), the destination SIP server 14 transmits the incoming response message 200OK. The SIP server 13 transmits an incoming response message 200OK to the calling SIP server 13 (S205), and the SIP server 13 receives the incoming response message 200OK to the host 11 again (S206). After that, the host A 11 transmits a response acknowledgment message (ACK) indicating that the incoming response is well received to the SIP server 13 (S207), and the SIP server 13 to the called SIP server (S208), and the called party. The SIP server 14 transmits a response acknowledgment message (ACK) to the host B 12 (S209) When a response acknowledgment message is received to the host B 12, the real-time communication protocol in both directions. It is: (RTP Realtime Transfer Protocol) session is set up enabling the communication between the host A (11) and a host B (12) (S210).

During communication, when the host A 11 sends a message BYE for terminating a session to the SIP server 13 (S211), the SIP server 13 sends this session end message BYE to the called SIP server 14 (S212), the destination SIP server 14 delivers the session end message (BYE) to the host B (12) (S213). When Host B 12 sends a response message (200OK) for this session termination message to the called SIP server 14 (S214), the called SIP server 14 sends a response message (200OK) for ending this session. Is sent to the calling SIP server 13 (S215), and when the calling SIP server 13 sends a response message (200OK) for terminating the session to Host A 11 (S216), the RTP session ends at this time. do.

As mentioned above, the session initiation protocol typically does not support resource reservation for providing an appropriate quality of service. Therefore, in recent years, researches related to so-called QoS Enabled Session Initiation Protocol (Q-SIP), which can support the appropriate quality of service required by the user in the session initiation protocol, are being actively conducted. As a result, network models such as integrated services and differential services, which are representative technologies for guaranteeing service quality on the Internet, are introduced, and some additional messages are added in addition to the existing session initiation protocol messages.

First, the integrated service model, which is a representative model among technologies for providing quality of service, uses a resource reservation protocol (RSVP) to provide appropriate quality of service. In the resource reservation of the integrated service, the calling party sends a PATH message that specifies the traffic characteristics to the called party. The route message stores the address and status information on the route, which is used by the called host to route the resource reservation message to the calling host. All routers on the path send the route message on the next hop as determined by the routing protocol.

The receiver receiving the route message transmits a resource reservation (RESV) message in response to the route message for the resource request of the flow. Intermediate routers on the path may accept or reject resource reservation messages. If the resource reservation request is rejected, the router rejecting the request sends an error message to the called party and connection establishment ends with failure. If the request is accepted, the link bandwidth and buffer space for that flow are allocated and the relevant flow state information is stored in the router.

As it allocates resources of a router to specific traffic, stream, or flow, it is very important to store and process information related to connection status. However, in order to maintain the state of all flows through all the routers in the network, the router uses a lot of memory and requires a lot of traffic flows (Policing). This feature is not a problem in narrow networks, but as the network grows in size, management difficulties arise, which can lead to scalability problems. Therefore, the integrated service model works more effectively on smaller networks than on larger networks.

In order to solve the problems of the integrated service as described above, the differential service model has emerged. Differentiated service model moves away from the concept of providing different quality of service for each traffic flow, and differentiates and operates the traffic by the set defined as Per Hop Behavior based on the set of several flows. The differential service renames the TOS field of IPv4 to the DS (Differentiated Service) field and redefines it, and defines a basic packet transmission method called PHB. In addition, the bandwidth broker of the differential service network manages the resource usage state in the network, and based on this, it performs the admission control for each class, which is a set of traffic flowing into the network.

In addition to INVITE, REGISTER, BYE, ACK, CANCEL, and OPTIONS of existing session initiation protocol, UPDATE, INFO, PRACK, MESSAGE, SUBSCRIBE, NOTIFY, REFER, etc. A new message has been added. Among these, the UPDATE message is used to change the state of a session before the destination host's incoming response message to the originating host's initial session request message (INVITE) arrives at the calling host, or the host end-to-end quality of service. Used to negotiate for provision. The PRACK message is a temporary response acknowledgment message for the response message 1xx indicating that the current session is in progress.

FIG. 3 is a message flow diagram illustrating a session initiation procedure that supports resource reservation in an integrated service model to provide a desired quality of service using a resource reservation protocol.

In FIG. 3, it is assumed that host A is a calling host and host B is a called host.

Host A 11 transmits a session request message (INVITE) to SIP server 13 to initiate a session with host B 12 (S301). Then, the calling SIP server 13 forwards the session request message (INVITE) to the called SIP server 14 (S302), and the called SIP server 14 sends the session request message (INVITE) to the host B 12. (S303). When the host B 12 transmits an incoming response message (200 OK) indicating that the host B 12 has received the session request message to the SIP server 14 (S304), the called SIP server 14 transmits to the calling SIP 13. In response to the incoming response message 200 OK (S305), the SIP server 13 receives the incoming response message (200 OK) to the host 11 again (S306). After that, the host A 11 sends an acknowledgment message (ACK) to the SIP server 13 indicating that the incoming response is well received (S307), and sends an acknowledgment message (ACK) transmitted from the originating SIP server 13. When the host SIP server 14 transmits to the host B 12 via the destination SIP server 14 and the destination SIP server 14 (S308 and S309), a resource reservation protocol is performed between the host A and the host B. The above operations from step S301 to step S309 are the same as the operations from step S201 to step S209 of FIG. 2.

Thereafter, the host A 11 transmits the quality of service requirements of the session to the routers of each path by using the path message. In FIG. 3, each host belongs to the integrated service network and passes through each resource reservation for RSVP. Since the number of routers varies depending on the network conditions, only the end of the calling party and the called party is shown.

The route message (PSVP PATH) from the host A (11) is delivered to the destination host B (12) via each route router in the integrated service network (S310). Then, the host B 12 receiving the path message (PSVP PATH) checks whether the session is allowed through the admission control module of the resource reservation protocol. If the host B 12 accepts the session, the path message is received. The resource reservation message (PSVP RESV) is transmitted to the host A 11 through the reverse path of the established path (S311), and the host A 11 receiving the resource reservation message (PSVP RESV) receives the reservation confirmation message (RSVP CONF). Are delivered to the host B 12 via each router 14 (S312).

In addition, in order to perform resource reservation in the reverse direction, the host B 12 transmits a route message (PSVP PATH) to each host A 11 via each route router (S313), and the host A 11 sends a host B ( 12, the resource reservation message (PSVP RESV) is transmitted (S314), and finally, the host B 12 transmits a confirmation message (RSVP CONF) for resource reservation to the host A (11) (S315).

When both paths and resources are reserved in this way and all signaling processing is completed, a real-time transport protocol (RTP) session is established between the host A 11 and the host B 12 to enable communication (S316).

On the other hand, if the session end message (BYE) transmitted from the host A (11) is transmitted to the host B (12) via the calling SIP server 12 and the called SIP server 12 (S317, S318, S319). The host B 12 transmits an incoming response message 200OK to the host A 11 via the called SIP server 14 and the calling SIP server 13 (S320, S321, and S322). In order to release the resource reservation on the path, the resource reservation protocol transmits a release message (RSVP TEARDOWN) in both directions and terminates the real-time transmission protocol (RTP) session (S323-S328).

When connecting a session through the resource reservation protocol, the SIP server participating in the session connection does not have any involvement in the resource reservation process for providing the quality of service required by the user. This means that the session establishment using the session initiation protocol and the resource reservation using the resource reservation protocol operate separately from each other. This causes some problems as follows.

First, because there is no network element that manages routers in the path participating in resource reservation, resource reservation cannot be performed by checking the resource status on the current network.

Secondly, if a user who actually participates in a session requires a higher quality of service for resource reservation than his or her own service quality level, which is contracted with the ISP, there is no way to prevent this.                         

Third, if the user actually lacks the resources required by the network, this means that the user cannot provide the service quality information to which the user belongs, and thus does not fulfill the initial contract regarding the service quality level between the user and the ISP.

Therefore, in order to control the quality of service required by a user using a SIP server, a policy server that manages routers and network equipment, manages resources of the entire network based on the user quality of service information, and controls user quality of service Interworking with the network server requires a new session initiation method and a network structure according to the interworking of the SIP server and the policy server.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to make use of the advantages of the integrated service and the differential service on the Internet, and each small access network of the calling party and the called party uses the integrated service, and the transmission network uses the differential service. In addition to the enhanced SIP server in a small access network with integrated services, a policy server for efficient network management and efficient quality of service can be installed. If the required resources are requested, the SIP server, the policy server, and the destination host initiate a session by performing admission control and resource reservation based on the current resource state.

In order to realize the above object, the resource management method for guaranteeing the end-to-end quality of service according to the present invention, if the originating SIP server requests the quality of service policy in response to the session start request of the originating host, the service quality policy management rule A first step of transmitting a session performance acceptance result according to the originating SIP server; A second step of, when the called SIP server requests a quality of service policy according to a request for initiating a session of the called host, transmitting a session performance acceptance result according to a quality of service policy management rule to the called SIP server; And a third step of establishing an RTP session between the originating SIP server and the terminating SIP server only when the session execution with respect to the originating SIP server is accepted and the session execution with respect to the terminating SIP server is accepted. In the first step, only when the sum of the session request band requested from the originating host and the current use band is smaller than the band threshold of each network element, the session performance of the quality of service policy for the originating SIP server is accepted. In step 2, the session performance of the quality of service policy for the incoming SIP server is accepted only when the sum of the current bandwidth used by the called host request band is less than the bandwidth threshold of each network element. .

In addition, in order to achieve the above object, in the session establishment method using the resource management method to ensure the quality of service between the host end-to-end according to the present invention, when the start of the session of the originating host is requested through the originating SIP server, A first step of identifying a source resource for the session; A second step of a terminating policy server confirming a terminating resource for the session; As a result of confirming the calling party resource and the called party resource, if the session execution is accepted, the session request is initiated to the called host through the called SIP server, and resource reservation is made between the calling host and the called host for the session connection. Performing a third step; And a fourth step of connecting the session when the called host responds to the session initiation, wherein in the first step, the origination policy server adds the sum of the session request band requested from the originating host and the current use band. The session execution is accepted only when the bandwidth is less than the bandwidth threshold of each network element, and in the second step, the terminating policy server adds the session request band requested from the destination host and the current use band, and the bandwidth threshold of each network element. It is characterized by accepting session only when it is smaller than the value.

In order to realize the above object, the session establishment system using the resource management method to ensure the quality of service between the host end-to-end in accordance with the present invention, Policy server for identifying the source and destination resources for the session establishment; A SIP server for requesting a policy related to a quality of service to the policy server when a session initiation is requested, so that resource reservation is performed between hosts when a session setup is accepted from the policy server; And requesting session initiation from the subscriber when the session initiation is requested from the subscriber, and initiating resource reservation with the counterpart host when the session initiation is requested from the SIP server, and SIP communication with the counterpart host through the SIP server when resource reservation is completed. And a host configured to establish a session, wherein the policy server adds a session request band requested from the host to a current use band based on a policy according to the quality of service rule. A session establishment system using a resource management method that guarantees the quality of service between the end-to-end, characterized in that the session is accepted only if smaller.

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

4 is a diagram illustrating an internet network to which an embodiment of the present invention is applied.

4 is a block diagram of an Internet network for ensuring a proper quality of service based on the session initiation protocol according to the present invention.

As shown, each small access network of the calling party and the called party consisting of integrated services transmits a session connection request from a client (host) to the called party in a plurality of hosts 41 and one access network, and reserves resources. SIP server 43 for requesting policy on the policy server, policy server 45 for determining policy on resource reservation from SIP server 43 and delivering it to SIP server and border router. The transport network is composed of a bandwidth broker 50 in charge of admission control and resource management of the differential service network, and boundary routers 51 and 52 connecting the integrated service network and the differential service network.

In the present invention, the policy server 45 manages the source resource and the destination resource for session establishment, it is possible to ensure the quality of service between the host end. The policy server 45 is equipped with a resource management table (see Table 1) to be described later.                     

In particular, in the present invention, the INVITE message transmitted by the hosts 11 and 12 to request the session initiation to the SIP server 13 and 14 includes service quality information requested by the user, and the service quality information is SDP. Add an attribute field to store this information. The SDP is a Session Description Protocol used for describing multimedia such as each video, voice, etc. that will use a session established using SIP.

In the present invention, the attribute field of the SDP added to include the QoS-related information required by the user is applied to each media field, and each subfield is a ststus-type indicating a processing state of the QoS-related information. Field, class no. Indicating the class of QoS for each media flow. Field, a define-type field indicating information related to traffic characteristics of a flow to be transmitted, and a direction-tag field indicating direction information of a flow to which QoS is to be applied.

FIG. 5 is a timing diagram illustrating a session initiation procedure for providing an appropriate quality of service according to the present invention in the Internet network configured as described above.

In FIG. 5, it is assumed that host A is a calling host and host B is a called host.

Host A 41 transmits to the SIP server 43 a session request message (INVITE) describing quality of service attributes such as resource reservation degree required for initiating a session with host B 42 (S501). The SIP server 43, which has received the session request message (INVITE) from the host A 41, transmits a REQ LDP message to the policy server 45 before delivering the session request message (INVITE) to the called party. Request (S502). Before delivering the session request message (INVITE) to the called party, the SIP server 43 requests a policy related to the quality of service to the policy server 45 as described above. The policy server 45 managing the access side access network is provided. Because it monitors and manages the current resource usage status, it may not be able to accommodate the resource reservation requirement required by Host A according to the resource usage situation of the access network. Therefore, as described above, by controlling the admission of resources in the originating network before the session is connected, it is possible to prevent the case where only the session is connected without the resource reservation required by the host.

The policy server 45, which has received a request for a quality of service policy from the SIP server 43, determines a policy according to a quality of service policy management rule in the policy server 45, and the determined policy uses dynamic resources. It is determined whether this is necessary (S503).

As a result of the determination in S503, if the determined policy does not require dynamic resource use (No in S503), the determined policy is transmitted to the SIP server 43 and the entrance border router 51 (S503, S504).

If, as a result of the determination of S503, if the determined policy requires dynamic resource use (YES in S503), the policy server 45 of the access network transmits a REQ LDP message to the bandwidth broker 50 of the transport network (S506). The bandwidth broker 50 allows the policy decision in consideration of the session request message. Accordingly, the bandwidth broker 50 transmits the determined policy to the router of the transport network that it manages, including the policy server 45 of the access network and the entrance boundary router 51 through the DEC LDP message, and transmits the determined policy to the policy server. At step S507 and S508, the controller 45 informs the router 45 and the router. Thereafter, the policy server 45 transmits the DEC LDP message to the calling SIP server 43, and notifies the determined policy (S509). In FIG. 5, not all routers belonging to each IP network are shown in order to reduce the complexity of the description, and only the edge routers are shown.

The originating SIP server 43 receiving the policy from the policy server 45 requests the session initiation to the destination SIP server 44 through the INVITE message (S510), and the receiving SIP server 44 receiving the message is transmitted. Requests a policy related to the quality of service through the REQ LDP message to the policy server 46 managing the called party's access network (S506).

The policy server 46 that has received the policy determines the policy according to the service quality policy management rule, and determines whether the determined policy requires dynamic resource use (S512).

As a result of determination in S512, if the determined policy does not require dynamic resource use (No in S512), the policy is transmitted to the destination SIP server 44 and the exit boundary router 52 through the DEC LDP message (S513, S514). ).

As a result of the determination in S512, if it is determined that the determined policy requires the use of dynamic resources (Yes in S512), the quality of service related policy is requested to the bandwidth broker 50 through the REQ LDP message (S515). Accordingly, the bandwidth broker 50 transmits the policy determined through the DEC LDP message to the SIP server 44 and to all the routers of the transmission network managed by the same, including the boundary router 52.

The destination SIP server 44 that receives the policy from the policy server 46 or the bandwidth broker 50 through the DEC LDP message transmits an INVITE message to the destination host B 42 that is the last session connection counterpart (S519). ).

The destination host B 42 receiving the session connection request determines whether the session can be performed or not, and if the acceptance is determined, in response thereto, 183 Session Progress, a message indicating that session establishment is in progress. ) Send a message (S520). The SIP server 44 receiving the 183 session progress message from the destination host B 42 forwards the 183 session progress message to the calling SIP server 43 (S521), and the calling SIP server 43 hosts the host message. Transfer to A (41) (S522). At this time, the 183 session progress message transmitted from the destination host B 42 indicates that the originating host A 41 is performing a request regarding the quality of service required so far, and the host A 41 is bidirectional. If RSVP resource reservation is desired, the request is sent to sender-> recipient if the resource reservation is completed. In FIG. 5, it is assumed that the originating host A 41 requests a resource reservation in both directions.

The originating host A 41 receiving the 183 session progress message sends a temporary response acknowledgment (PRACK) message to the SIP server 43 (S523), and the SIP server 43 sends a call to the called SIP server 44. The side SIP server 44 finally transmits a temporary response acknowledgment (PRACK) message to the host B 42 (S524 and S525). The temporary response acknowledgment message (PRACK) not only needs an additional message to the session establishment situation that has been carried out until now, but also informs the called party that the 183 session progress message has arrived correctly. The receiving host B 42 forwards the incoming response message for the temporary response acknowledgment message to the calling host A 41 in the reverse direction (S526, S527, and S528).

The called party Host B 42 sends an incoming reply message (200 OK) and simultaneously from the called host B 42 to the calling host A 41, the calling host A 41 sends an incoming reply message (200 OK). ), And at the same time, resource reservation in both directions is executed from the source host A 41 to the destination host using RSVP, respectively (S529 to S546).

While the session is set in the resource reservation, the policy server 45 and 46 of each access network and the bandwidth broker 50 of the transmission network check the resource status of the IP network managed by the resource reservation in advance and whether or not to reserve the resource. Since it is determined and delivered, each session (router) of the complex and inexpensive IP network can be progressed without asking whether to accept each node, so that session initiation can be performed simply and clearly. It has an effect. In addition, if the host itself does not support RSVP resource reservation, the policy server directly forwards the policy to each pass-through router to allocate the amount of resources required by the host during the session connection process. When connected, it can be more flexible to provide the quality of service required by the host.

Both the source host A 41 and the destination host B 42 receive an RSVP CONF message and an RSVP RESV message, indicating that resource reservation was successful from the calling party to the called party and the called party from the calling party.

Thereafter, the called host B 42 is the called SIP server 44, the called SIP server 44 is the calling SIP server 43, and the calling SIP server 43 is the calling host 41. C) transmits a 180 ringing message 180 RINGING from the called host B 42 to the calling host A 41 (S547-S549).

The host A 41 which has received the call back is the calling SIP server 43, the calling SIP server 43 is the calling SIP server 44, and the called SIP server 44 is the called host B 42. By sending a temporary response acknowledgment message (PRACK) to each, it is informed that the session setup process up to now is proceeding as required, and that no additional message for the current situation is needed (S550-S552).

In response, the destination host B 42 receives the incoming response message 200OK for the temporary response message PRACK and the incoming response message 200OK for the original session request message INVITE. The calling party's SIP server 44 sends the incoming response messages to the calling SIP server 43, and the calling SIP server 43 first sends the incoming response messages to the originating host A. The process then transmits to 41 (S553 to S558).

Finally, host A 41 sends a response acknowledgment message for the initial session initiation request to host B 42 via the calling SIP server 43 and the called SIP server 44, and then host A 41 and host B. An RTP session is established between the 42 and communication is possible (S559-S561).

When the session is established and communication is performed (S562), the policy server updates the resource usage situation of each network element to which the session is connected to the actual resource usage situation of the current state.

6 is a message when a user requests a higher quality of service than a quality of service to which he / she belongs and requests for session establishment when applying a session establishment method of guaranteeing end-to-end service quality according to an embodiment of the present invention. It is a flow chart.

In FIG. 6, it is assumed that host A 41 is the calling host and host B 42 is the called host.

Host A 41 transmits to the SIP server 43 a session request message (INVITE) describing quality of service attributes such as resource reservation degree required for initiating a session with host B 42 (S601). The SIP server 43 receiving the session initiation request from the host A 41 requests a policy related to the quality of service to the policy server 45 through the REQ LDP message (S602).

Accordingly, the policy server 45 grasps the service quality information to which the user belongs based on the user information. However, the user recognizes that a higher quality of service is required than the quality of service to which he belongs, and transmits a quality of service policy policy message to the SIP server 43 through the DEC LDP message (S603). The SIP server 43 receiving the message transmits the required quality of service disallowed message to the calling host A 41 requesting the initial session initiation through a SIP message (580 Precondition-Failure) (S604), and receives the received host A (41). ) Requests for session initiation again (S605).

FIG. 7 illustrates that when a session establishment method using resource management for guaranteeing service quality between hosts ends according to an embodiment of the present invention, a user requests resource reservation regarding a quality of service to which a user belongs in an originating access network. It is a message flow diagram for explaining the case where the resource is insufficient for it. In FIG. 7, it is assumed that host A 41 is a calling host and host B 42 is a called host.

Host A 41 transmits to the SIP server 43 a session request message (INVITE) describing quality of service attributes such as resource reservation required to initiate a session with host B 42 (S701). The SIP server 43, which has received the session initiation request from the host A 41, requests a policy related to the quality of service to the policy server 45 through the REQ LDP message (S702).

The policy server 45 grasps the service quality information to which the user belongs based on the user information, and grasps that the resource reservation that satisfies the service quality class to which the user belongs is requested. However, the policy server 45 currently managing resources on the network recognizes that the resources remaining on the network are shorter than the resources required by the user, and through the DEC LDP message, the quality of service policy required by the SIP server 43 is not available. Deliver the message (S703).

The SIP server 43 receiving the notification notifies the originating host A 41 requesting the initial session initiation via a SIP message (580 Precondition-Failure) that the required quality of service is impossible (S704), and receives the received host A (41). ) Requests for session start again (S705).

FIG. 8 illustrates that when a session establishment method for guaranteeing end-to-end quality of service according to an embodiment of the present invention, a user requests resource reservation regarding a quality of service to which he belongs, and a policy server 45 in an originating access network. Message flow in the case that the user has finished accepting the resource, but the resource of the called party's access network is not enough. In FIG. 8, it is assumed that host A 41 is a calling host and host B 42 is a called host.

Host A 41 transmits to the SIP server 43 a session request message (INVITE) describing quality of service attributes such as resource reservation required for initiating a session with host B 42 (S801). The SIP server 43, which has received the session initiation request from the host A 41, requests the quality of service policy from the policy server 45 through the REQ LDP message (S802).

The policy server 45 grasps the service quality information to which the user belongs based on the user information, and grasps that the resource reservation that satisfies the service quality class to which the user belongs is requested. After recognizing the remaining resources on the network and the resources requested by the user, it is recognized that the resource reservation related to the quality of service requested by the user can be provided, and through the DEC LDP message, the SIP server 43 and the entrance boundary are identified. The determined policy is transmitted to the router 51 (S803 and S804). The SIP server 43 receives the SIP message 43 and delivers the SIP message (INVITE) to the called SIP server 44 (S805).

The destination SIP server 44 requests the policy regarding the quality of service to the policy server 46 through the REQ LDP message (S806). Currently, the destination policy server 46 that manages the resources on the destination network detects that the resources remaining on the network are shorter than the resources required by the calling user, and then the destination SIP server 44 through the DEC LDP message. The required quality of service policy message is transmitted (S807). The receiving SIP server 44 receives the received service quality impossible message to the calling SIP server 43 through the SIP message (580 Precondition-Failure) (S808), and the calling SIP server 43 receives the first three messages. The requested quality of service message is transmitted to the originating host A 41 requesting the session start (S809). Host A 41 receives this request for session initiation again (S810).

On the other hand, the configuration examples of the resource management tables mounted on the calling party and called party policy servers 45 and 46 according to the present invention are shown in <Table 1>.

<Table 1> Configuration example of resource management table mounted in Policy Server

Network elements A B C Current band U (a) U (b) U (c) Session request band R (a) R (b) R (c) Total bandwidth U (a) + R (a) U (b) + R (b) U (c) + R (c) Threshold C (a) C (b) C (c)

In <Table 1>, "network element" is network elements in a domain managed by the policy server 45 and 46, and "current use band" indicates resource usage status currently being used in each network element.

"Session Request Band" means the bandwidth required by the host to start the current session for proper quality of service, and the total required band is the current resource usage band of each network element and the session request band of the host that wants to start the session. Summing up. "Threshold" means the maximum value of resources that each network element can support. If the "total bandwidth" exceeds the "threshold" as described above, the session connection is rejected, and the "total bandwidth" is set. If less than "threshold", accept the session connection.

Hereinafter, a process of making a policy decision when the policy server having the resource management table as described above receives a policy decision request from the calling SIP server 43 or the called SIP server 44 will be described.

When Host A 41 requests a session using the session initiation protocol, the originating SIP server 43 receives the policy decision about the currently requested session from the Policy Server 45 maintaining the resource management table. Requires.

At this time, the policy server 45 checks the resource management table managed by the policy server 45 to determine whether to accept the session.

The policy server 45 determines the required bandwidth based on the user ID in the policy decision request message received from the SIP server 43. That is, the session request band requested from the current host A 41 is R ( kbit / s ), the current use band of each network element is U (kbit / s), and the band threshold of each network element is C (kbit / s). Let's say s).

The policy server 45 recognizes that the band requested from the host A 41 is R, and determines the path of the network elements that can be connected to the session by using the resource management table of the network elements in the domain that it manages.

For ease of explanation, assume that network elements A, B, and C are selected. The policy server 45 first adds the session request band R (a) required by the current host to the current use band U (a) of the network element A selected in the path combining step, thereby defining a resource threshold predefined in the network element A. Will be compared with C (a). Comparing this, if the sum U (a) + R (a) does not exceed the threshold C (a), the session is accepted. When accepting the session, the policy server 45 stores this summed value U (a) + R (a) as the total required bands, respectively.

In the embodiment of the present invention, when the U (a) + R (a) summed in the session acceptance step is managed as a temporary use band, when the end-to-end RTP session is connected for the session connection, the temporary use band is the total required band It can also be updated to be managed.                     

Each network element B, C also performs the same process as the resource management table management method of A.

As described above, according to the resource management method for guaranteeing the end-to-end service quality according to the embodiment of the present invention, the session establishment method and the system using the same, the policy is determined according to the resource usage state of each network element before connecting the session. The server decides whether or not to accept the session in advance and, if accepted, provides the resource reservations required by the user, providing more flexible and streamlined service quality when the actual RTP session is connected. have.

In addition, when the present invention is applied, since the resource reservation of the service quality required by the user is surely provided before the RTP session is established, the service satisfaction can be improved in providing multimedia services such as voice, data, and video. have.

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

Claims (24)

delete A first step of, if the originating SIP server requests the quality of service policy according to the originating host's request, transmitting the session performance acceptance result according to the quality of service policy management rule to the originating SIP server; A second step of, when the called SIP server requests a quality of service policy according to a request for initiating a session of the called host, transmitting a session performance acceptance result according to a quality of service policy management rule to the called SIP server; And And a third step of establishing an RTP session between the originating SIP server and the terminating SIP server only when the session execution with the originating SIP server is accepted and the session execution with the terminating SIP server is accepted. Accepts the session performance on the quality of service policy for the originating SIP server only when the sum of the session request band requested from the originating host and the current use band in the first step is less than the band threshold of each network element; In the second step, the session performance of the quality of service policy for the incoming SIP server is accepted only when the sum of the current use bands to the session request bands requested by the destination host is smaller than the band threshold of each network element. A resource management method that guarantees a host end-to-end service quality. 3. The method of claim 2, wherein performing a session for the quality of service policy of the first step comprises: And if the session request band requested from the originating host is higher than the contracted quality of service level with the originator, rejecting the end-to-end service quality of the host. delete The method of claim 2, wherein the performing of the session on the quality of service policy of the second step comprises: And if the session request band requested from the called host is higher than a contracted quality of service level with the called party, refusing to perform the session. The method of claim 2, wherein the first step A step 1-1 of requesting a policy from a bandwidth broker if it is determined that the policy according to the quality of service policy management rule requires dynamic resource use; And transmitting the session performance acceptance result determined by the bandwidth quality-related policy of the bandwidth broker to the originating SIP server. The method of claim 2, wherein the second step Step 2-1 of requesting a policy from a bandwidth broker if it is determined that the policy according to the quality of service policy management rule requires dynamic resource use; And a step 2-2 of transmitting a session performance acceptance result determined by the bandwidth broker quality of service policy to the incoming SIP server. delete delete delete A first step of the originating policy server identifying the originating resource for the session when a request for initiation of the session of the originating host through the originating SIP server is requested; A second step of a terminating policy server confirming a terminating resource for the session; As a result of confirming the calling party resource and the called party resource, if the session execution is accepted, the session request is initiated to the called host through the called SIP server, and resource reservation is made between the calling host and the called host for the session connection. Performing a third step; And If the called host responds to the session initiation, there is a fourth step of connecting the session, In the first step, the originating policy server accepts the session only when the sum of the session request band requested from the originating host and the current use band is smaller than the band threshold of each network element. In the second step, the terminating policy server accepts session execution only when the sum of the session request band requested from the terminating host and the current use band is smaller than the band threshold of each network element. Session establishment method using resource management method to guarantee service quality. The method of claim 11, wherein the origination policy server, And if the session request band requested from the originating host is higher than the service quality grade contracted by the originating host, rejecting the session execution. 12. The method of claim 11, wherein the identifying of the called party's resources in the second step comprises: a second step of the called SIP server requesting a service related policy from the called policy server; And When the session policy is accepted by the terminating policy server, the terminating SIP server informs the originating SIP server that the session is in progress, and when a temporary response confirmation message is transmitted from the originating SIP server, the terminating response is sent to the originating SIP server. And a 2-2 step of transmitting a message. delete The method of claim 11, wherein the incoming policy server is And if the session request band requested by the called host is higher than the service quality grade promised by the called subscriber, rejecting performance of the session. 12. The system of claim 11, wherein the origination policy server If the determined quality of service policy requires dynamic resource use, request a policy from the bandwidth broker to determine the session execution result based on the quality of service policy determined by the bandwidth broker. Session establishment method using resource management method to guarantee security. The method of claim 11, wherein the incoming policy server is If the determined service quality-related policy requires dynamic resource use, request a policy from a bandwidth broker to determine a session execution result based on the service quality-related policy determined by the bandwidth broker. Session establishment method using resource management method to guarantee quality. delete delete A policy server for identifying a calling party resource and a called party resource for establishing a session; A SIP server for requesting a policy related to a quality of service to the policy server when a session initiation is requested, so that resource reservation is performed between hosts when a session setup is accepted from the policy server; And When session initiation is requested from the subscriber, request session initiation to the SIP server; when session initiation is requested from the SIP server, resource reservation is made with the partner host; when resource reservation is completed, SIP communication is performed with the partner host through the SIP server. Host to establish a session, The policy server Based on the policy according to the quality of service rules, the host to accept the session only when the sum of the session request band requested from the host and the current use band is less than the band threshold of each network element. Session establishment system using resource management method to guarantee end-to-end service quality. The method of claim 20, wherein the policy server The session establishment system using the resource management method that guarantees the end-to-end service quality, characterized in that the session request bandwidth from the host is higher than the service quality grade that the subscriber requesting the session is higher than the agreed service quality level. . 21. The method of claim 20, further comprising a bandwidth broker for determining a service quality related policy corresponding to the request if the service quality related policy is requested from the policy server, and then notifying the policy server and routers of the service quality related policy. Session establishment system using a resource management method to ensure the quality of service between the end-to-end host characterized in that it comprises. The method of claim 22, wherein the policy server If the quality-related policy is determined to require dynamic resource use, request the quality-related policy to the bandwidth broker, and transmits the session performance acceptance result transmitted from the bandwidth broker to the SIP server Session establishment system using resource management method to guarantee end-to-end service quality. delete

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