Engineering Clinic

Queuing in NS2 (RED Queue and SFQ) HARDWARE / SOFTWARE REQ UIRED: Network Simulator-2 Operating System – LINUX ( UBUNTU ) THEORY: Queue Management is defined as the algorithm that manages the length of the packet queues by dropping packets when necessary. From the point of packet dropping, Queue management can be classified into 2 types Passive Queue Management: In Passive Queue Management the packet drop occurs only when the buffer gets full. Ex: Drop Tail. Active Queue Management: Active Queue Management employs preventive packet drops. It provides an implicit feedback mechanism to notify senders of the onset of congestion. Arriving packets are randomly dropped. Ex: RED. Drop Tail:  In this packets are dropped from the tail of the queue. Once the buffer gets full, all arriving packets are discarded. Packets already in the queue are not affected. Figure 2.1: Drop Tail mechanism As shown in figure 2.1, the arriving packet gets dropped from the tail when the queue is filled. Random Earl