This paper presents one of the features of DS

(Differentiated Services) architecture, namely the queuing or

congestion management. Packets can be placed into separate

buffer queues, on the basis of the DS value. Several forwarding

policies can be used to favor high priority packets in different

ways. The major reason for queuing is that the router must hold

the packet in its memory while the outgoing interface is busy with

sending another packet. Our main goal is to compare the

performance of the following queuing mechanisms: FIFO (First-

In First-Out), CQ (Custom Queuing), PQ (Priority Queuing),

WFQ (Weighted Fair Queuing), CBWFQ (Class Based Weighted

Fair Queuing) and LLQ (Low Latency Queuing).