When classifying and marking traffic, a recommended design principle is to classify and mark applications as close to their sources as technically and administratively feasible. As the line between…

Dedicating each application class to its own queue is a queuing strategy, not a marking standard, and does not address interoperability between different vendors or administrative domains.

Implementing QoS in hardware versus software affects performance and enforcement capacity but does not establish a standards-based marking scheme needed for cross-domain interoperability.

DSCP PHB (Differentiated Services Code Point Per-Hop Behavior) markings are defined by IETF standards (RFC 2474/2475) and are recognized by virtually all modern network equipment regardless of vendor. Using these standard markings ensures that QoS policies applied at the source are honored end-to-end across enterprise and service provider domains. They remain valid as the network expands or integrates new technologies, directly satisfying the interoperability and future expansion requirement.

Policing traffic near the source is a rate-enforcement mechanism that limits traffic flows but does not establish a standards-based marking scheme recognized across different network administrative domains.