Patent Application
20080071914
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2006-254245 filed on Sep. 20, 2006, the content of which is incorporated by reference.
1. Field of the Invention
The present invention relates to client-server communication in a packet-based communication network.
2. Description of the Related Art
In recent years, studies on the next generation communications network utilizing IP(Internet Protocol) technology to be provided by telecommunications carriers have been extensively carried out. The next generation communications network is called NGN (Next Generation Network) or the like (ITU-T recommendation Y. 2001[December 2004] see “General overview of NGN”). The NGN is expected to achieve cost reduction of public networks by use of IP technology.
The facilities for standardization, namely, ETSI(European Telecommunications Standards Institute), ITU-T (International Telecommunication Union Telecommunication Standardization Sector) have been making progress in standardizing protocols in order to realize this next generation communications network.
The existing IP networks represented by the Internet have a cost advantage but there is anxiety in terms of communication stability and reliability. For example, there is a higher risk of data delay and loss occurring compared to the public networks provided by telecommunication carriers. However, both low cost and communication stability and reliability are expected and demanded for next generation networks that will be offered by telecommunications carriers.
One of the causes that gives rise to data delay and loss can be considered to be that the bandwidth required for stable communication can not be always secured in IP networks. To deal with this, the next generation networks often adopt a method of communication whereby a session is established first between a server and a client with whom communication will take place, and then the bandwidth is managed for every session. Establishment of this session is permitted on the condition that the necessary bandwidth is secured. Thus, the necessary bandwidth is assured between the server and client, with whom a session has been established, so that it is possible to achieve stable communication. As one example of the session control protocols to be used in next generation communication networks to secure the necessary bandwidth, SIP (session Initiation Protocol) can be listed.
In order to perform such bandwidth management, it is possible that a session controller for managing allocation of a bandwidth to each session will be provided for next generation networks. A server and a client establish a session after getting permission from such a session controller, so that it becomes possible to receive and transmit data in a stable manner within the permitted bandwidth.
The above-described technology, however, has the following problem.
There are cases in which, in order to transmit and receive data on a bandwidth guaranteed network that secures the bandwidth for the communication between a server and a client by establishment of a session, the server and client need to include a session control protocol. However, of the information communicating devices such as existing servers and clients, there are those which have no such a session control protocol. As a result, there is a possibility that such information communicating devices cannot support communication whose bandwidth is secured by such a session.
An exemplary object of the invention is to provide a system and a device which, on a bandwidth guaranteed network that secures a bandwidth for client-server communication by establishment of a session, enables communicating devices having no session control protocol for securing a bandwidth to perform bandwidth-secured communication therebetween.
In order to achieve the above object, an exemplary aspect of the invention is a session control system which controls a bandwidth securing session on a bandwidth guaranteed network in which bandwidth-secured packet-based communication is enabled by management of the band securing session, and includes a first session proxy device and a second session proxy device.
The first session proxy device is disposed between a client device not having a control protocol for bandwidth securing sessions installed therein and a bandwidth guaranteed network. In place of the client device the first session proxy device establishes a bandwidth securing session in the bandwidth guaranteed network when the client device performs communication over the bandwidth guaranteed network.
The second session proxy device is disposed between a server device having no control protocol for bandwidth securing sessions installed therein and the bandwidth guaranteed network. In place of the server device, the second session proxy device establishes a bandwidth securing session with the first session proxy device when the server device performs communication over the bandwidth guaranteed network.
The above and other objects, features, and advantages of the present invention will become apparent from the following description with references to the accompanying drawings which illustrate examples of the present invention.
A mode for carrying out the exemplary embodiment will be described in detail with reference to the drawings.
Bandwidth guaranteed network 10 is an IP network that is offered by a telecommunications carrier, and is a communication network that enables bandwidth secured communication. The bandwidth between client 11 and APL server 14 in bandwidth guaranteed network 10 is secured when session proxy devices 12 and 13 establish a session after gaining a permission from session controller 16 inside bandwidth guaranteed network 10. In bandwidth guaranteed network 10, SIP, for example is used as the control protocol for bandwidth securing sessions.
Session controller 16 manages the allocation of bandwidth resources on bandwidth guaranteed network 10, and when receiving a request for securing a bandwidth from session proxy devices 12 and 13, the controller determines whether the request can be accepted or not based on the allocation status of bandwidth resources. If the request is accepted, a bandwidth securing session is established whereas no bandwidth securing session is established if the request is not accepted.
APL server 14 is a server device for offering an application service to client 11 by way of bandwidth guaranteed network 10. APL server 14, in response to a request from client 11, offers an application service to client 11. Examples of applications include on-demand contents distribution and exchange of files based on FTP. APL server 14 has no control protocol (SIP herein is one of the examples) for controlling bandwidth securing sessions on bandwidth guaranteed network 10.
Client 11 is a client device for utilizing an application presented by APL server 14. Client 11 accesses to APL server 14 to request an application service. Similarly to APL server 14, client 11 has no control protocol for controlling bandwidth securing sessions on bandwidth guaranteed network 10.
When an application service is offered from APL server 14 to client 11, both client 11 and APL server 14 establish a session (to be referred to hereinbelow as a “session for applications”) therebetween to be used for presenting an application. This session for applications is controlled by a control protocol that is different from that for bandwidth securing sessions. The control protocol of the session for applications is installed beforehand in both APL server 14 that presents applications and client 11 that uses applications.
Session proxy devices 12 and 13 establish a session in place of client 11 and APL server 14, which include no control protocol for bandwidth securing sessions, to secure the bandwidth. For this purpose, session proxy devices 12 and 13 have been installed with a control protocol for bandwidth securing sessions. When session proxy device 12 establishes a bandwidth securing session, it acquires the necessary bandwidth information from APL bandwidth manager 15.
APL bandwidth manager 15 is a device for managing the bandwidth that will be needed for the application service presented by APL server 14. APL bandwidth manager 15 has bandwidth management data that was recorded to represent the correspondence between the types of applications and the bandwidths to be secured for those applications, stored beforehand. When receiving an inquiry about the necessary bandwidth for an application, APL bandwidth manager 15 searches for the necessary bandwidth from the bandwidth management data in answer to the query, and gives back the necessary bandwidth information.
Referring to
Upon receiving an application connect request, session proxy device 12 holds it and establishes a bandwidth securing session with session proxy device 13 and executes a bandwidth securing process (Step 104). As a result of this process, a bandwidth securing session with the necessary bandwidth secured is established between session proxy device 12 and session proxy device 13 (Step 105).
Subsequently, session proxy device 12 sets up a TCP connection with session proxy device 13 (Step 106). As a TCP connection has been established between session proxy device 12 and session proxy device 13, session proxy device 12 sends the application connect request that was received from client 11 at Step 103 (Step 107).
Then, session proxy device 13 sets up a TCP connection with APL server 14 (Step 108). As a TCP connection has been established between session proxy device 13 and APL server 14, session proxy device 13 sends the application connect request received at Step 107 to APL server 14 (Step 109).
After this condition is met, the bandwidth securing session with the necessary bandwidth secured between session proxy device 12 and session proxy device 13 is established while a session for applications is established between client 11 and server 14. Accordingly, it is possible for client 11 and server 14 to perform stable application communication therebetween with the bandwidth secured (Step 110).
When the service is ended after the application communication is completed, client 11 disconnects the application communication between client 11 and APL server 14 (Steps 111 to 113).
Then, APL server 14 disconnects the TCP connection with session proxy device 13 (Step 114). Session proxy device 13 disconnects the TCP connection with session proxy device 12 (Step 115). Session proxy device 12 disconnects the TCP connection with client 11 (S116).
As the TCP connection between client 11 and session proxy device 12 is disconnected, the application terminates at client 11 (step 117).
Also, session proxy device 12 performs a process of cutting the bandwidth securing session with session proxy device 13 (Step 118). This process frees the bandwidth having been secured between session proxy device 12 and session proxy device 13 (Step 119).
Referring to
In the process of establishing a SIP session at Steps 104 and 105 in
Subsequently, “200 OK” that indicates acceptance of the request is sent from session proxy device 13 to session controller 16. Also, “200 OK” is sent from session controller 16 to session proxy device 12. In response to this, “ACK” that indicates an understanding is sent from session proxy device 12 to session controller 16, and “ACK” is sent from session controller 16 to session proxy device 13.
Referring to
Also, in the TCP connecting process at Step 108 in
Referring to
Also, in the TCP disconnecting process at Step 115 in
Further, in the TCP disconnecting process at Step 116 in
Next, in the SIP session freeing process at Steps 118 and 119 in
Referring to
Application communicator 21 relays and transfers the data that is exchanged between client 11 and APL server 14.
Session control protocol communicator 24 exchanges control signals, based on the control protocol for bandwidth securing sessions, with bandwidth guaranteed network 10, in accordance with the instructions from session control protocol processor 23.
Bandwidth information manager 25 acquires the information on the bandwidth to be secured for applications, from APL bandwidth manager 15 by way of bandwidth information communicator 26. Though it is specified herein that bandwidth information manager 25 acquires the information on the bandwidth from APL bandwidth manager 15, the invention should not be limited to this. As another example, bandwidth information manager 25 may, by itself, have the bandwidth management data, which was recorded to represent the relationship between the types of applications and the bandwidths to be secured for those applications, stored beforehand. In this case, if bandwidth information manager 25 receives an inquiry about the bandwidth for the designated application type, from session control protocol processor 23, the manager may determine the information on the bandwidth to be secured for the application based on its own bandwidth management data and respond to session control protocol processor 23. As a still another example, the application connect request from client 11 may be adapted to contain the bandwidth information that shows the necessary bandwidth. In this case, bandwidth information manager 25 may determine the bandwidth to be secured for the application, based on the bandwidth information contained in the application connect request.
Bandwidth information communicator 26 communicates with APL bandwidth manager 15 following instructions from bandwidth information manager 25 to make an inquiry, and bandwidth information communicator 26 may acquire the information on the bandwidth to be secured for the application.
Application proxy processor 22 monitors the data that is being relayed and transferred by application communicator 21, and gives a notice to session control protocol processor 23 if there is a request for connection or disconnection of an application.
When a request for establishment of a session for applications is made from client 11 to APL server 14, application proxy processor 22 temporarily holds the request instead of transmitting it to APL server 14 and informs session control protocol processor 23 of the fact of reception of the application connect request. This information contains the information representing the type of the application. Then, upon receiving the notice from session control protocol processor 23, indicating that a bandwidth securing session has been established, the processor 22 transmits the request for establishment of a session for applications, which has been retained, to APL server 14 by way of bandwidth guaranteed network 10.
On the other hand, when a request for disconnection of a session for applications is made from client 11 to APL server 14, application proxy processor 22 sends the request to APL server 14 and then notifies session control protocol processor 23 of the fact of reception of the application disconnect request.
Session control protocol processor 23 has a session control protocol function for bandwidth securing sessions, and in accordance with the notice from application proxy processor 22, establishes or disconnects a bandwidth securing session with session proxy device 13 on the APL server 14 side by way of session control protocol communicator 24. The bandwidth securing session is established with the condition that permission is obtained from session controller 16 or in one word, that the bandwidth has been secured.
Upon receiving a notice that indicates reception of an application connect request from application proxy processor 22, session control protocol processor 23 executes a process of establishing a bandwidth securing session with session proxy device 13 on the APL server 14 side. During this process, session control protocol processor 23 acquires the information on the bandwidth to be secured for the application communication, from bandwidth information manager 25. Then, as the bandwidth securing session through the secured bandwidth has been established, session control protocol processor 23 notifies application proxy processor 22 of the fact that the bandwidth securing session has been established.
When receiving a notice that indicates reception of an application disconnect request from application proxy processor 22, session control protocol processor 23 executes a process of disconnecting the bandwidth securing session with session proxy device 13 on the APL server 14 side.
Referring once again to
Application communicator 31 relays and transfers the data that is exchanged between APL server 14 and client 11.
Session control protocol communicator 34 exchanges control signals based on the control protocol for bandwidth securing sessions, with bandwidth guaranteed network 10, in accordance with the instructions from session control protocol processor 33.
Application proxy processor 32 monitors the data that is being relayed and transferred by application communicator 31, and gives a notice to session control protocol processor 33 if there is a message relating to connection or disconnection of an application.
Session control protocol processor 33 has a session control protocol function for bandwidth securing sessions, and in accordance with a request from session proxy device 12 on the client 11 side, establishes or disconnects a bandwidth securing session with session proxy device 12 by way of session control protocol communicator 24.
As has been described above, according to the exemplary embodiment, since session proxy device 12, in place of client 11, and session proxy device 13, in place of APL server 14, control the establishment and disconnection of a bandwidth securing session so as to maintain and free the bandwidth for application communication between client 11 and APL server 14, it is possible to achieve bandwidth secured communication even if client 11 and APL server 14 have no control protocol for bandwidth securing sessions installed therein.
Further, according to the exemplary embodiment, since session proxy device 12 first checks the bandwidth that is needed for the application that will be used by client 11, and then secures the necessary bandwidth, it is possible to secure the bandwidth that is needed by the application communication.
It should be noted that session proxy device 12 and session proxy device 13 in the exemplary embodiment may be realized by a computer, which has the programs for executing the functions of the individual components shown in
While preferred embodiments of the present invention have been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-254245 | Sep 2006 | JP | national |
