y string, autonomous system and prefix, user can classify packets into QoS group by using group ID. Traffic can be classified by using QoS group marking within a router, but the same classification cannot be made for the packets leaving the router. Total of 100 different QoS group marking can be set up by the user. Class Based Packet Marking User can differentiate packets for providing QoS by using class based packet marking. This scheme provides efficient packet marking which can be used to differentiate packet based on these designated marking. It performs following tasks: Packets can be marked by setting up of IP precedence bit or IP differentiated service code point termed as DSCP in IP ToS byte. Packet can be marked by setting up of layer2 CoS value A local QoS group value can be associated with the packet. Restrictions With Class-Based Packet Marking Feature It can mark only packets travelling on CEF switching paths. To use this, configure CEF in both interfaces receiving and sending the packets. Class-based packet marking feature can be configured on sub interface, interface or an ATM PVC, but not supported on following set of interface types: fast Ethernet channel b. Tunnel Downloaded: 4/15/2022 9:44:49 AM Nova Southeastern University IP Address: 137.52.76.29 Quality of Service in SDN Technology ATM switched virtual circuit (SVC) that is data link connection identifier any interface that doesn't support CEF Policy Based Routing (PBR) Functionality like protocol sensitive routing, equal access, source sensitive routing, routing based on dedicated links, routing based on interactive versus batch traffic services are provided by policy based routing. Policy based routing is done by means of BGP attributes that are set using route map. Random Early Detection (RED) Random early detection congestion avoidance algorithm is used to drop incoming packets with increasing probability, as average utilization of buffer increases. Each time a packet arrive at the queue, the router determine the utilization at that time