Only the CIR and PIR values can be specified with percent, not the burst sizes; the burst sizes are configured in units of milliseconds. If the CIR is configured in percent, the PIR also must be. When the service-policy is attached to an interface, the CIR (and PIR, if configured) is determined as a percentage of the interface bandwidth. If desktop software inventory is changed, the CIR and PIR values and burst sizes automatically are recalculated using the new interface bandwidth value. For subinterfaces, the bandwidth of the main interface is used for the calculation. For ATM, the VC bandwidth is used; for Frame Relay, the CIR value of the PVC is used.
Scheduling is the process of deciding which packet to transmit next. Scheduling occurs when the interface is experiencing congestion, but also (unlike queuing) when the interface is not experiencing congestion (that is, there is still a decision, albeit a simple one, of which packet should be transmitted next, even if there is no congestion on the interface). If there is no congestion on the interface, packets are transmitted as they arrive. If the interface is experiencing congestion, queuing algorithms are engaged. However, the scheduler still has to decide which queue to service next
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment