Traffic classification differentiates services by packet classification according to the characteristics of user Ethernet packets and certain rules, to implement different processing operations and provide different services.
The purpose of traffic classification is to differentiate traffic streams to provide quality of service (QoS) guarantee for services. The system completes service mapping and prepares for consequent QoS behaviors based on the traffic stream. The consequent QoS actions include switching between the user VLAN and the network VLAN, upstream and downstream CAR, priority marking, and queue scheduling.
Traffic classification is an important function because quality of service (QoS) policies only apply to the traffic flows that are classified.
Marking refers to remarking the IP priority or differentiated services code point (DSCP) of IP packets. Classification refers to classifying data packets based on multiple priorities or service classes. If the first three bits (IP priority) of the ToS field in the header of IP packets are used to mark the packets, the packets can be classified into a maximum of eight classes. If the DSCP is used to mark packets, the packets can be classified into a maximum of 64 classes.
The multi-dwelling unit (MDU) supports two traffic classification policies: IP priority, and DSCP of IP packets. After the packets are classified, other QoS features can be applied to different classifiers to implement classifier-based congestion management and traffic shaping.
After packets enter the MDU, the MDU classifies them and provides different QoS services for different traffic flows.
Traffic classification on the MDU
Traffic classification is implemented in the SERVICE-PORT, TAG-TRANSFORM parameter.
Two aspects are taken into account to configure the classification:
• No implementation of VLAN processing: default / add-double / transparent
• Implementation of VLAN processing: traslate / traslate-and-add
service-port 300 vlan 2500 adsl 0/12/12 vpi 0 vci 35 single-service tag-transform add-double inner-vlan 500 rx-cttr6 tx-cttr6
