Networking Requirements
As shown in Figure 1, the network provides voice, video, and data services, with priorities in descending order. When different service flows arrive at the ISP network, devices on the ISP network must identify priorities of the services to provide differentiated services.
A switch can identify packets based on priority fields, such as 802.1p or DSCP. When packets arrive at the switch, the switch maps packet priorities to local priorities and drop priorities, and provides different QoS services based on the local priorities and drop priorities.