Classification is the process of putting traffic into a class. Whereas, marking is the process of marking the class with a distinct identifier.
Traffic can be classified based upon different values such as source IP address, DSCP value, IP precedence value, MPLS experimental value, port number, .... When traffic enters the ingress interface of a device it will be classified, if classification is configured. Once traffic has been classified, the traffic will be marked based upon its classification. Traffic can be marked using a DSCP value, IP precedence value, ToS bits, or QoS group number. This marked value is what tells the other devices the level of service to provide to the traffic. Traffic can also be remarked. Remarking traffic occurs when the traffic has already been marked with a value and then that value gets replaced with another value. The reason you always see these two QoS mechanism clumped together is because, typically, the same technology performs classification and marking, such as CAR or Class-based marking. I hope this helps. Carl Timm, CCIE# 7149 Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=48685&t=48645 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
