the IP header. The classifier has a single input and splits the incoming stream into a number of outgoing ports in terms of different PHB aggregates. Meters measure the temporal properties of the stream of packets selected by a classifier against a traffic profile. A meter passes state information to other conditioning functions to trigger a particular action for each packet, which is either in-profile or out-of-profile. Markers set the packet with a particular code point, adding the marked packet to a particular DiffServ behavior aggregate. An existing marking may be changed. It may also use the statistics gathered by a meter to decide on the level of a packet's conformance to its allocated rate characteristics. For a non-conformant stream, it takes action by re-marking the packet in either a class with lower priority, or lower drop precedence. Shapers delay some or all of the packets in a traffic stream in order to shape the stream into compliance with a traffic profile. Droppers discard some or all of the packets in a traffic stream in order to bring the stream into compliance with a traffic profile. There are two major kinds of dropping elements in a DiffServ router: absolute and algorithmic. - An absolute dropper is simply used to drop the overload traffic of a real-time application, e.g. for the EF PHB, because an overly delayed packet is no longer useful, and is better discarded. Therefore, when congestion happens, the real-time packets are forwarded to this block in the DiffServ node. When real-time traffic misbehaves, the overload traffic is sent to the absolute dropper. 3.4 IP-Based UTRAN - In contrast, an algorithmic dropper drops a packet according to a specific algorithm, usually well before the queue is full. Random Early Detection (RED) (see Appendix A.6) is such an algorithmic dropper, suggested for avoiding congestion in the network. It detects the incipient congestion and notifies the congestion manager of the source to decrease its flow rate. This way, congestion is avoided. To perform RED per 