1. Field of the Invention
The present invention generally relates to SIP (Session Initiation Protocol), and more particularly to system and method for sharing SIP sessions.
2. Description of the Prior Art
SIP (Session Initiation Protocol) is a growing communication solution. It is more flexible and cheaper than traditional circuit switched communication network. Traditionally, SIP users have to register user accounts in order to facilitate SIP functionalities. The registered user accounts are managed, charged, and billed by service providers.
In a scenario, a certain number of SIP subscription accounts are applied by a company or an organization. However, the number of employees or member of this company or organization is often more than the subscription account number. Therefore there is no one-to-one mapping existed between accounts and the phones of employees. In the consequence, external caller cannot call a specified employee directly, and vice versa. The problem could be addressed in two reasons. First, since internal SIP phones do not register to external SIP server, outer SIP phones could not find these un-registered SIP phones. Second, these un-registered internal SIP phones could not dial out via the external SIP server.
Accordingly, there exists a need for a system and method for sharing the SIP sessions registered at external service providers.
Therefore, in accordance with the previous summary, objects, features and advantages of the present disclosure will become apparent to one skilled in the art from the subsequent description and the appended claims taken in conjunction with the accompanying drawings.
An object of this present invention is to provide a communication system, which comprises a SIP (Session Initiation Protocol) call server and a virtual SIP user agent. SIP services are provided by said SIP call server for a plurality of internal SIP user agents. The virtual SIP user agent is connecting to said SIP call server and an external SIP proxy server. At least one external SIP account is registered by said virtual SIP user agent to said external SIP proxy server. SIP communication between any of said plurality of internal SIP user agents and an external SIP user agent is exchanged by said virtual SIP user agent.
Another object of this invention is to provide a communication method, which comprises providing a SIP (Session Initiation Protocol) call server. SIP services are provided by said SIP call server for a plurality of internal SIP user agents. The method further comprises providing a virtual SIP user agent connecting to said SIP call server and an external SIP proxy server. At least one external SIP account is registered by said virtual SIP user agent to said external SIP proxy server. Moreover, the method also comprises exchanging, by said virtual SIP user agent, SIP communication between any of said plurality of internal SIP user agents and an external SIP user agent.
The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the description serve to explain the principles of the disclosure. In the drawings:
The present disclosure can be described by the embodiments given below. It is understood, however, that the embodiments below are not necessarily limitations to the present disclosure, but are used to a typical implementation of the invention.
Having summarized various aspects of the present invention, reference will now be made in detail to the description of the invention as illustrated in the drawings. While the invention will be described in connection with these drawings, there is no intent to limit it to the embodiment or embodiments disclosed therein. On the contrary the intent is to cover all alternatives, modifications and equivalents included within the spirit and scope of the invention as defined by the appended claims.
It is noted that the drawings presents herein have been provided to illustrate certain features and aspects of embodiments of the invention. It will be appreciated from the description provided herein that a variety of alternative embodiments and implementations may be realized, consistent with the scope and spirit of the present invention.
It is also noted that the drawings presents herein are not consistent with the same scale. Some scales of some components are not proportional to the scales of other components in order to provide comprehensive descriptions and emphasizes to this present invention.
Please refer to
As shown in the
Please refer to
As shown in the
Please refer to
As shown in the
In this present invention, the call flow of system 100 could be configured as
Please refer to
In an example, the automatic attendant flow 313 may comprises a series of voice prompts for the caller, the external user agent 126. Following the series of voice prompts, the caller may sends extension number referred to the intended internal user agent 122. After receiving the extension number, the virtual user agent 126 could call the callee internally. In another example, the external user agent 126 could send some information referred to one department, one functional group, or even another automatic attendant flow. Then the virtual user agent 126 could call the dynamically determined callee after receiving the information provided by the automatic attendant flow 313.
As shown in the
If the intermediated virtual user agent 126 does not want to bridge the media stream, it could ask the caller talking to the callee directly. A REFER message, augmented with the address of callee, is sent to the external SIP proxy 110 by the virtual user agent 126 at step 330. Next, the REFER message is forwarded to the caller at step 332. If the caller agrees, an acceptance message would be returned to the virtual user agent 126 at steps 334 and 336. In this regards, another INVITE message, augmented with the address of callee as replacement, is sent to the external SIP proxy server 110 at step 338. This INVITE message would be forwarded to the internal SIP call server 120 at the following step 340. At step 342, a new INVITE message, issued by the internal SIP call server 120, would be received by the callee, the internal user agent 122. Therefore, a corresponding OK message and a corresponding ACK message are exchanged between the caller and callee at the following steps 344, 346, 348, 350, 352, and 354. It means an end-to-end two-way media stream path is built up between the caller and the callee. After that, at steps 356, 358, 360, and 362, a BYE message and a corresponding OK message are exchanged between the callee and the virtual user agent 126 in order to abandon the media stream between them.
In the mentioned call flows, the external user accounts could be shared by the internal user agents via the bridge of virtual user agent. It may save some basic charges of external user accounts and/or raise utilization rate of external user accounts.
The foregoing description is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obvious modifications or variations are possible in light of the above teachings. In this regard, the embodiment or embodiments discussed were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the inventions as determined by the appended claims when interpreted in accordance with the breath to which they are fairly and legally entitled.
It is understood that several modifications, changes, and substitutions are intended in the foregoing disclosure and in some instances some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.