2nd International ICST Workshop on Intelligent Networks: Adaptation, Communication & Reconfiguration

Research Article

Call Admission Control: QoS Issue for VoIP

  • @INPROCEEDINGS{10.1109/COMSWA.2008.4554512,
        author={Mohammad Asadul Hoque and Farhana Afroz},
        title={Call Admission Control: QoS Issue for VoIP},
        proceedings={2nd International ICST Workshop on Intelligent Networks: Adaptation, Communication \&  Reconfiguration},
        keywords={call admission control; bandwidth ; circuit-switched; RSVP; OSPF-TE; RTCP;(key words)},
  • Mohammad Asadul Hoque
    Farhana Afroz
    Year: 2008
    Call Admission Control: QoS Issue for VoIP
    DOI: 10.1109/COMSWA.2008.4554512
Mohammad Asadul Hoque1,*, Farhana Afroz2,*
  • 1: Database Administrator, IT Division TM International Bangladesh Limited (AKTEL) Dhaka, Bangladesh
  • 2: Department of Mechanical Engineering Bangladesh University of Engineering and Technology Dhaka, Bangladesh
*Contact email: asad1752@ieee.org, diba_mym@yahoo.com


One of the vital key elements for providing Quality of Service (QoS) for VoIP is the Call Admission Control (CAC) capabilities of the Session Management /Call Session Control Function or gateway. Even though the network may be designed to meet a given performance and restoration objective for the engineered traffic loads, the actual traffic may be significantly higher. Without a CAC function in a VoIP network during overloads, links become congested and new calls keep getting admitted. All calls in progress, not just the new calls start dropping packets and experiencing longer delays. Contrast this to a circuit switched network, where new calls get blocked, but calls in progress experience good call quality. In the VoIP case, packet loss could become large enough that calls become unintelligible, callers hang-up their call, and most will reattempt. This paper gives an overview of potential CAC approaches, highlighting four basic alternatives; based on endpoint performance measurements, path-based bandwidth management, link-based bandwidth management, and per-call bandwidth reservation. The paper also recommends a link bandwidth management approach for its scalability and efficacy.