PointRed Telecom Ltd. MCRD-2458 Manuale Utente

M i c r o R e d   &   M i c r o V i e w   N M S   U s e r   M a n u a l   v 1 . 0

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Figure 81. Policy Parameters 

This is the rate (expressed in kbits/s) which is guaranteed that will always be 
available to the respective traffic class. Apparently, the CIF dedicated for a 
specific class, can not exceed the network bandwidth available. When multiple 
competing classes exist for the same interface and for the same direction 
(output/input), the sum of all of them should also not overrun the available 
bandwidth. 

Note that, regardless of the CIR the traffic is always transmitted at the maximum 
speed supported by the physical interface. Literally, the CIR expresses the 
average rate in which the traffic is sent, in due time. 

This is the maximum rate (in kbits/s) in which, the traffic of a class, can be sent 
or received (in average). Even if no other traffic competes for the bandwidth, this 
barrier can not be exceeded. This value can be as large as the capacity of the 
link and as small as the CIR.  

The bandwidth between CIR and PIR is not guaranteed for a class. The 
possibility for a class to exploit this range, depends on its priority as we will see 
later.

Some applications are characterized by short periods of intensive network usage 
and long periods with no network usage at all. For instance, when we browse the 
Internet, our web browser requests a web page and then remains idle for a long 
period of time, until another page is requested. 

Such applications are not served well by the CIR/PIR mechanism alone. The EBS 
mechanism remedies this problem by allowing an application to send a number