When the number of packets to be sent out through an interface exceeds the capacity of the link, the packets need to be queued so that they can be transmitted on the interface when the bandwidth is available.
In the DiffServ mode, the traffic is classified as discussed in the earlier section, and the different types of traffic are put in different queues on the egress interface. The number of queues on the egress interface depends on the hardware and software capabilities of the device, as the DiffServ architecture only defines the behavior and does not specify the internal implementation.
Queuing for the already-marked packets is shown in the following figure:
The three types ...