You are a network engineer tasked with implementing Quality of Service $($QoS$)$ mechanisms to prioritize traffic and ensure optimal performance on a corporate network.

$2\mathrm{.}1$ Explain the importance of packet classification in the context of QOS and describe how it facilitates the implementation of differentiated treatment for various types of traffic.

$(9$ marks$)$

$2\mathrm{.}2$ Policy enforcement mechanisms include marking, queuing, policing, and shaping, briefly describe any $3$ marking techniques used with Qos.

$(6$ Marks$)$