# Multiclass MLPPP Traffic Classes Overview

A traffic class is a system-wide collection of buffers, queues, and bandwidth that you can allocate to provide a defined level of service to packets in the traffic class. With multiclass MLPPP, high-priority and low-priority data packets are fragmented into their respective QoS traffic classes before being transmitted. The QoS traffic classes are each mapped to a separate multilink class.

The major benefits of mapping traffic classes to multilink classes are:

- The multiclass MLPPP feature supports the mapping of up to eight traffic classes. You can fragment data packets into a maximum of eight different priorities of traffic classes.
- Classes of higher-priority can be interleaved between classes of lower priority, which reduces transmission latency.
- Every multilink class has its own transmit and receive context. These contexts ensure that data packets of higher priority traffic classes are received in the order they were transmitted.

The default traffic class is the best-effort traffic class. You can configure fragmentation and reassembly on all traffic classes. Any packet without a traffic-class-to-multilink-class mapping is transmitted without a multiclass MLPPP header.

#### Related Topics

- Configuring Traffic Classes on Multiclass MLPPP Interfaces
- Multiclass MLPPP Overview
- Traffic Class and Traffic-Class Groups Overview