Electrical computers and digital processing systems: multicomput – Computer network managing – Computer network monitoring
Reexamination Certificate
1999-11-26
2003-07-29
Maung, Zarni (Department: 2154)
Electrical computers and digital processing systems: multicomput
Computer network managing
Computer network monitoring
C709S204000, C709S227000
Reexamination Certificate
active
06601099
ABSTRACT:
This application claims priority under 35 U.S.C. §§119 and/or 365 to 19985567 filed in Norway on Nov. 27, 1998; the entire content of which is hereby incorporated by reference.
FIELD OF THE INVENTION
The present invention relates to telecommunications. More particularly, and not by way of limitation, the present invention is directed to a method for extending the use of SIP (Session Initiation Protocol).
More specifically the present invention relates to such a method for facilitating the charging of such SIP connections.
TECHNICAL BACKGROUND
The Problem
SIP, as described in Handley et. al., “SIP: Session Initiation Protocol”, is a competitive protocol to H.323, which is described in ITU-T, “document packet-based multimedia communications systems”, to allow Multimedia applications to operate over the IP protocol. The Internet Engineering Task Force (IETF) has standardized SIP. The latest version of SIP is currently only a draft, provided by the Multi-party Multimedia Session Control (MMUSIC) working group (WG) in IETF.
The SIP protocol supports most of the features of the H.323 protocol, but it is simpler in respect to a number of different messages. The fact that SIP is simpler than H.323 makes it easier to make a SIP-compliant end-point than an H.323-compliant end-point. New development tools and programming languages also make it easier to control media-interferences. This also makes it easier to make a multi-media end-point. When making an end-point, it is also easy to add additional logic and functionality beyond what is stated in the standard.
One of the methods for performing charging for SIP or H.323 conversations is to place the charging logic inside a SIP server or a gatekeeper (H.323), as illustrated in FIG.
1
.
One of the problems with SIP is that it does not have support for a typical “continue call” message. Another problem is that SIP-complaint end-points could send the CLOSE message directly to each other instead of via a SIP server. This makes it difficult to support charging for SIP conversations. The reason for this is that the media traffic is not sent via the gatekeeper or the SIP server, and it is difficult to know when the conversation is closed.
Known Solutions
In the H.323 standard there is support for a “continue call” message. In the Q.931 signaling protocol part of H.323, which is described in the ITU-T standard, the message is called “status inquiry” In the RAS part of H.323 the IPR message can be used for the same purpose. In H.323 it is also required that the end-points send the “closed conversation” message via the gatekeeper (if a gatekeeper-routed call model is used).
OBJECTS OF THE INVENTION
An object of he present invention is to provide a method by which the use of SIP (Session Initiation Protocol) is extended in a rational and expedient manner.
A further object of the present invention is to provide a method by which it is radially observed when a conversation between two end-points is concluded.
A still further object of the present invention is to provide a method by which charging for SIP conversations can be stipulated in a very accurate and expedient manner.
A still further object of the present invention is to provide a method by which the message “continue call” is favourably supported by a corresponding SIP server.
BRIEF DISCLOSURE OF THE INVENTION
These objects are achieved in a method as stated in the preamble, which is characterised by the features as stated in the characterising clause of the enclosed patent claim 1.
In other words, the present invention can be defined as an extension of the SIP protocol, the main idea of the present invention being that the missing “continue call” message is solved by sending extra INVITE messages to the SIP server.
REFERENCES:
patent: 6178439 (2001-01-01), Feit
patent: 6430176 (2002-08-01), Christie, IV
Handley et al. “Internet-draft: SIP: Session Initiation Protocol”, Internet Engineering Task Force, 1998, pp. 1-118.*
Schulzrinne et al. RFC 1889, Internet Engineering Task Force, 1996, pp. 1-75.*
M. Handley et al., “SIP: Session Initiation Protocol”, Network Working Group Request for Comments: 2543, Mar. 1999. pp. 1-153.
ITU-T—Telecommunication Standarization Sector of ITU—Q.931; “Digital Subscriber Signalling System No. 1 (DSS 1)—ISDN User-Network Interface Layer 3 Specification for Basic Call Control”; Series Q: Switching and Signalling Digital Subscriber Signalling System No. 1—Network Layer; May 1998. pp. 1-388.
ITU-T—Telecommunication Standarization Sector of ITU—H.323; “Packet-Based Multimedia Communications Systems”; Series H: Audiovisual and Multimedia Systems Infrastructure of audiovisual services—Systems and terminal equipment for audiovisual services; Feb. 1998. pp. 1-114.
Clinton Gregory
Maung Zarni
Telefonaktiebolaget LM Ericsson (publ)
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