The COPS
protocol has been designed to enable communication on the interface between the
policy decision administrator and the policy enforcement devices in a
policy-based networking environment. It can be recognized that on the same
interface there is the need to transfer information related to the request of
resource by QoS clients and for the allocation of resources by resource
allocation servers (e.g., band-width broker) in a DiffServ network. Hence, it
is sensible to add this resource allocation functionality in the COPS
framework. In particular, there are at least two cases where it is sensible to
use COPS. The first case is on the interface between an edge node and a
resource control node for handling resource allocation in a network provider
domain. The second case is on the interface between a customer (client of a QoS
enabled network) and the network provider: here COPS can be used as a protocol
to signal dynamic admission control requests. In this article we present the
definition of a new COPS client type to support the above-mentioned
functionality, then describe an application scenario where SIP-based IP
telephony applications can use DiffServ-based QoS networks. Simple
backward-compatible enhancements to SIP are needed to interact with COPS/DiffServ
QoS. A Testbed implementation of the proposed solutions is finally described.