Telephonic communications – Plural exchange network or interconnection – Interexchange signalling
Reexamination Certificate
1999-08-04
2001-11-27
Hong, Harry S. (Department: 2742)
Telephonic communications
Plural exchange network or interconnection
Interexchange signalling
C370S389000, C370S401000, C379S207030, C379S230000
Reexamination Certificate
active
06324279
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to allocating network resources. More specifically, the present invention relates to reserving and committing network resources based on an authorized quality of service.
The known signaling architecture H.323 is an International Telecommunications Union (ITU) defined standard that describes how multimedia communications occur between terminals, network equipment and services on local area networks (LANs) and wide area networks (WANs) that do not provide a guaranteed quality of service (such as Internet Protocol (IP) networks). Quality of service is a measure of communication service quality during a call, and can include, for example, the bandwidth, delay and latency associated with the call. In networks using connectionless “best effort” delivery models, the quality of service typically is not guaranteed; the H.323 is a signaling architecture for such a network.
The H.323 provides a range of implementation options including gatekeeper-routed signaling. In the H.323 standard, gatekeepers map LAN address aliases to IP addresses and provide address lookups when needed. Gatekeepers also exercise call-control functions to limit the number of H.323 connections and the total bandwidth used by these connections in an H.323 “zone.” Although the gatekeeper is not necessary within the H.323 standard, when a gatekeeper is present in a network, network terminals must make use of its services. In other words, gatekeepers maintain state information for each individual call and all call signaling must pass through the gatekeepers.
The gatekeeper implementation of the H.323 standard, however, suffers several shortcomings. First, the equipment associated with gatekeepers needs to be extremely reliable so that the gatekeeper is available throughout the course of the call. If the gatekeeper-related equipment fails during a call, the call fails because the state information for the call maintained solely at the gatekeeper is lost. Second, the gatekeeper-related equipment likely cannot scale in a cost effective manner because maintaining the state information and performing the messaging associated with H.323 is complex and processor intensive. Finally, theft of service is possible by bypassing the gatekeepers to place unauthorized and unmonitored calls.
SUMMARY OF THE INVENTION
Signaling messages are exchanged for a call between a calling party to a called party. A setup message for the call is exchanged through at least one gate controller. Network resources are reserved for the call based on the exchanged setup messages. An end-to-end message for the call is exchanged without the end-to-end message being routed through the at least one gate controller.
REFERENCES:
Michelle Blank, “H.323 Gatekeepers Essential Software for IP Telephony and Multimedia Conferencing”, CTI Developer, Feb. 1998, pp. 94-98.
Shykeh Gordon, Radvision, Inc., “H.323 The Multimedia Communications Standard moves from Consensus to Compliance”, CTI Developer, vol. 2(2), pp. 108, 110-113.
VCON Inc., “H.323 Standard”, Jan. 1998, pp. 1-22.
R. Braden Ed. et al., Standards Track, Resource ReSerVation Protocol (RSVP), Version 1 Functional Specification, Sep. 1997, pp. 1-92, http://www.cis.ohio-state.edu/htbin/rfc/rfc2205.html.
Thom G A: “H. 323: The Multimedia Communications Standard for Local Area Networks”, IEEE Communications Magazine, US, IEEE Service Center, Piscataway, NJ, vol. 34, no. 12, Dec. 1996.
Kalmanek Jr. Charles Robert
Marshall William Todd
Mishra Partho Pratim
Nortz Douglas M
Ramakrishnan Kadangode K.
AT&T Corp.
Hong Harry S.
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