This means that Web services access is denied to
requests from users who did not negotiate the level of QoS with the selected Web
services providers.
???. User Profile Manager: The User Profile Manager is responsible for managing users??™
preferences and their required QoS. This allows the user to update its preferences and
required QoS after receiving, for example, a certain level of QoS.
??? QoS.Negotiator: The QoS Negotiator is in charge of conducting and managing the
negotiation process through a negotiation protocol. At the end of negotiation and after
an agreement is reached, the QoS negotiator defines and issues the clauses of the QoS
contract, which specifies what the provider should deliver, the guaranteed QoS, and
the cost. The contract is stored in the broker??™s database, and a copy of it is sent to both
the user and the provider.
??? Selection.Manager: The Selection Manager is in charge of implementing different
selection policies in order to provide an acceptable quality of service to the users.
These policies can range from simple policies, as random and round-robin, to complex
ones taking account of the current state of servers in terms of availability, load, and
level of quality of service which they can deliver.
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