2.1.4 Resource Sharing Requirements

The allocation of resources is typically negotiated on a flow-to-flow basis as each flow requests admission to the network. The quantity of primary interest in resource-sharing is aggregate bandwidth on individual links. There are examples that are commonly used to explain the requirement of link sharing among collective entities: 2.1.5 Packet Dropping:

As cited in [RFC 1633],in many audio and video streams , some packets are more valuable than others. Hence a "preemptible" packet service, is introduced whereby some of the packets within a flow could be marked as preemptible.When  the network is in danger of not meeting some of it's quantitative service commitments, it can use the preemptibility option and discard the packet thereby reducing the delays of the not-preempted packets.

2.1.6 Auditing:-

This is called as "usage feedback" [RFC 1633]  to prevent abuse of the network resources.

2.1.7 Reservation Model:-

This describes as to how an application negotiates for a QoS level. The simplest model is that the application asks for a particular QoS and the network either grants it or refuses.Many applications will be able to get acceptable service from a range of QoS levels , or more generally, from anywhere within some region of the multidimensional space of a flowspec.