![packetstream against tos packetstream against tos](https://i.ytimg.com/vi/Njlq_IJ1MYI/maxresdefault.jpg)
To provide such QoS assurances, IETF proposed two broad models: DiffServ and IntServ.
![packetstream against tos packetstream against tos](http://www.thesempost.com/wp-content/uploads/2016/12/google-automated-queries-300x150.png)
These time sensitive applications demanded strict control in packet loss rate, inter-packet delay and jitter. With rapid expansion of Internet, newer applications requiring a greater degree of Quality of Service (QoS) were developed and deployed on it. The sender fully relied on the network for successful delivery of packets to the destination.
![packetstream against tos packetstream against tos](https://i.redd.it/vtezqtk9cy751.jpg)
Traditionally Internet was designed for data traffic and was called as a ‘best effort’ network. At the receiver when the weighted average delay experienced by these probe packets is found to be within a threshold the flow is admitted else rejected. In this design, an end host first probes the network by sending probe packets at the rate equal to the peak rate of the flow to be admitted in to it. The proposed admission control when integrated with DiffServ based IP network offers a better Quality of Service (QoS) to the data flows admitted in to it. In this study, a probing based endpoint admission control scheme operating on inter-packet delay is proposed. Information Technology Journal, 5: 448-453. QoS Provisioning Through a Delay Based Endpoint Admission Control for a DiffServ Network. The simulation results show better performance in terms of higher bottleneck link utilization and a stable, moderate average and peak inter packet delay. The proposed scheme admits a flow of packet stream only when sufficient network bandwidth is available. For this it is proposed to make use of an endpoint admission control strategy with inter-packet delay estimation as the admission decision criteria. The policies thus defined do not ensure that the network is not congested. An aggregate is a user defined entity which usually includes network traffic requiring similar QoS treatment. The packets entering a DiffServ network experience a quality of service based on the per hop behaviors defined for different aggregates.