Forwarding Class | Juniper Networks Certified Associate Junos Exam

CD

A forwarding class is a classification mechanism used in Junos OS to identify and differentiate types of traffic. It allows network administrators to assign different levels of service to different types of traffic, based on specific criteria.

The two purposes of a forwarding class are as follows:

1. To classify traffic: A forwarding class is used to classify traffic into different categories based on criteria such as source or destination address, protocol, or port number. By classifying traffic in this way, network administrators can apply different policies and quality of service (QoS) settings to each category of traffic. For example, video traffic might be assigned to a high-priority forwarding class, while file transfers might be assigned to a lower-priority class.

2. To identify traffic that should receive common treatment: Once traffic has been classified into different forwarding classes, each class can be assigned specific QoS settings, such as guaranteed bandwidth, queueing priority, or packet loss priority. This allows network administrators to provide different levels of service to different categories of traffic, depending on their importance or sensitivity. For example, voice traffic might be assigned a higher priority forwarding class than data traffic, to ensure that it receives low-latency, high-quality service.

Therefore, the correct answers to this question are B. to classify traffic, and C. to identify traffic that should receive common treatment. Answers A and D are incorrect because a forwarding class is not used to identify traffic that should be dropped or to assign traffic to output queues directly. However, a forwarding class can indirectly affect which packets are dropped or sent to which output queues, by influencing the QoS settings that are applied to each class of traffic.