Each queue is serviced based on the user-configured CIR and PIR values. If the packets that are collected by a scheduler from a queue are flowing at a rate that is less than or equal to the CIR value, then the packets are scheduled as in-profile. Packets with a flow rate that exceeds the CIR value but is less than the PIR value are scheduled as out-of-profile. Figure: 4-Priority Scheduling depicts this behavior by the ‟In-Prof” and ‟Out-Prof” labels. This behavior is comparable to the dual leaky bucket implementation in ATM networks. With in-profile and out-of-profile scheduling, traffic that flows at rates up to the traffic contract (that is, CIR) from all the queues is serviced prior to traffic that flows at rates exceeding the traffic contract. This mode of operation ensures that Service Level Agreements are honored and traffic that is committed to be transported is switched prior to traffic that exceeds the contract agreement.
A profile is an arithmetical analysis of the rates that are permitted for a particular packet flow; therefore, profiled scheduling may also be called rate-based scheduling.