CCNA 3 Enterprise Networking, Security, and Automation, Version 7.0 Practice Exam

The term that refers to adding a value to the packet header to ensure it aligns with a defined policy is traffic marking. Traffic marking involves adding specific identifiers, often referred to as tags or markings, to packets as they traverse through a network. This practice is essential in quality of service (QoS) implementations, where priority and resource allocation need to be defined based on the type of traffic or specific network policies.

By marking packets, network devices such as routers and switches can make informed decisions about how to handle each packet as it moves through the network. For instance, packets marked for higher priority might be given preferential treatment in terms of bandwidth allocation or reduced latency.

In contrast, while packet filtering involves examining and approving or denying packets based on specific criteria, it does not involve modifying the packet itself. Traffic shaping manages congestion by controlling the flow of packets, but it doesn't typically entail adding values to headers like traffic marking does. Packet encapsulation refers to wrapping data with headers and trailers for transport but is not specifically about adding values for policy enforcement.