User guide

QoS implementation for DIFFSERV QOS
7-13
iMG/RG Software Reference Manual (Quality of Service)
7.1.3.4.5 Scheduling packets
Packets forwarded to the Scheduler are buffered internally in multiple queues based on the scheduling priority
value associated with each packet. If the Algorithmic Dropper is associated with that particular queue then the
Dropper will be invoked, at the time of enqueuing, to decide whether the packet should be enqueued in the
queue or dropped.
The flow chart below summarises the scheduling process for packet enqueuing.
FIGURE 7-4 Scheduling Process for Packet Enqueuing
Enqueue
Get scheduling priority associated with the packet.
Get the queue corresponding with the scheduling priority
Enqueue packet
in the queue
Invoke ALD
Drop the Packet
ALD configured for queue
for given scheduling priority?
Should the packet
be dropped?
Is the queue full
STOP