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Please use this identifier to cite or link to this item: http://www.lib.ncsu.edu/resolver/1840.16/1754

Title: COPS Usage for Managing Media Authorization
Authors: Khan, Khurram Matin
Advisors: Dr Douglas Reeves, Committee Chair
Dr Mihail Devetsikiotis, Committee Member
Dr Peng Ning, Committee Member
Keywords: policy control
Media Authorization
RSVP
Quality of Service
QoS
Internet Telephony
SIP
COPS
Issue Date: 6-Sep-2002
Degree: MS
Discipline: Computer Networking
Abstract: The unreliable nature of packet networks leads to unpredictable service for the end user. It is hence desirable to negotiate end-to-end QoS before establishing multimedia calls. Different mechanisms for the reservation of resources have been defined to allow guaranteed service levels on packet networks, e.g. Resource Reservation Protocol (RSVP) and Differentiated Services (Diffserv). Authorization of network resource usage is, however, necessary before the resources can be reserved for a host and a multimedia session is established. To prevent fraud and facilitate a coherent view of the resource usage throughout the network, coordination between call signaling and resource reservation is necessary. The media authorization framework being developed by IETF addresses these issues. When a host initiates a multimedia call, it is issued a media authorization token. This token is then transparently forwarded to the network edge router with the resource reservation request sent by the host. We have identified a few requirements that are not addressed by the current framework. For example, the network currently has no way of revoking an already issued authorization. Proper checks need to be in place to ensure that the token is not misused. Also, there is a need for closer cooperation between the network elements to allow a consistent view of the resources reserved by the user. This is of special significance in situations where different administrative domains involved have service agreements based on the actual resource usage (e.g. for billing purposes). A solution is proposed to overcome these problems and afford new possibilities in the framework, like sub delegation of resources. The objective of the proposed extensions is to provide greater flexibility in the framework and facilitate better coordination between the session setup process and the reservation of resources. Common Open Policy Service (COPS) protocol is extended to exchange the additional messages and a new COPS client is defined.
URI: http://www.lib.ncsu.edu/resolver/1840.16/1754
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