| Call Admission Control |
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Information AboutCall Admission Control |
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Call Admission Control(CAC) is used to prevent congestion control in Voice Traffic. It is a preventive Congestion Control Procedure. It is used in the Call Setup phase. CAC can be used to prevent congestion in connection-oriented protocols such as ATM. There are several CAC schemes available, which are detailed in {Link without Title} . It can also be used in VoIP in order to ensure QoS, and prevent loss of packets. The difference between the former and the latter, however, is that VoIP uses RTP/UDP/IP, all of which are connectionless protocols. In this case, Integrated Services with RSVP (reserve resources for flow of packets through the network) using Controlled-Load Service is used in order to ensure that the call cannot be setup if it is not possible to support the flow described. Also, according to the External link specified below, CAC kicks in to reject calls when either there is insufficient CPU processing power, or the Upstream/Downstream traffic exceeds prespecified thresholds, or the number of calls being handled exceeds a prespecified limit. REFERENCES {Link without Title} Call admission control schemes: a review HG Perros, KM Elsayed, N Inc - IEEE Communications Magazine, 1996 - comsoc.org EXTERNAL LINKS
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