Bandwidth Allocation with Class-of-Service Components

C

The class-of-service (CoS) is a feature of Juniper Networks routers and switches that enables network administrators to classify, manage, and prioritize network traffic based on a set of rules or policies. CoS is used to ensure that mission-critical applications, such as voice and video, receive the necessary bandwidth and quality of service (QoS) they require, while less important traffic, such as web browsing or email, is given lower priority.

There are four main components of CoS, which are:

1. Classification: This component is used to identify and classify incoming network traffic based on various criteria, such as the source or destination IP address, protocol type, port number, and other packet attributes.

2. Rewrite marking: This component is used to modify the packet headers of the classified traffic to indicate the QoS treatment that it should receive downstream. This includes rewriting the 802.1p priority field, IP ToS or DSCP field, MPLS EXP field, or other header fields.

3. Scheduling: This component is used to allocate bandwidth to different traffic types based on their priority and bandwidth requirements. This is done by assigning each traffic class to a specific queue or buffer and then scheduling the transmission of packets from each queue in a fair and efficient manner.

4. Queuing: This component is used to store packets that are waiting to be transmitted on an interface. Each queue is assigned a specific priority level, and packets are serviced based on their priority and the scheduling algorithm used.

Based on the above, the correct answer to the question is C. Scheduling. This is because scheduling is the component that determines how much bandwidth is allocated to different traffic types. The other components of CoS are used to classify, mark, and queue traffic, but it is the scheduling component that controls how much bandwidth is allocated to each traffic class.