PointRed Telecom Ltd. MCRD-2458 Manuale Utente

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Figure 87. Overlapping Parallel Classes
9.4.3.
Class Hierarchy
Although the aggregated ftp traffic falls within limits (3000/3500), the maximum 
allowed bandwidth for each FTP server is restricted to 1750 kbps. An intuitive 
workaround would be to set the PIR of each class to 3500. However, in that 
case, if there is a lot of ftp traffic for both FTP servers, then the aggregated ftp 
traffic might exceed the desired restriction: 3500 (since 3500+3500=7000). In 
order to alleviate this problem, we will have to create a class hierarchy. 
1.
We set the CIR/ PIR of every class created up to now to 1499/ 3500 and we 
remove he application type of FTP. 
2.
We create two new classes, named ‘ftp_traffic_in’ and ‘ftp_traffic_out’. We 
set the CIR/ PIR on each of them to 3000/ 3500. Source IP/ Sub of 
‘ftp_traffic_in’ should be set to 192.168.1.0/ 24 and destination IP/ Sub of 
‘ftp_traffic_out’ to 192.168.1.0/ 24. This is to allow for other FTP sessions to 
take place. Next, on the MATCHES part, we set the port range to 20 – 21 
(FTP-Data, FTP-Control), and the protocol type to FTP.