R is used to set IP precedence for packets entering the network. Class Based Packet Marking User can differentiate packets by marking the packets based on designated marking. It allow user to perform following tasks: IP precedence bit or IP differentiated service code point termed as DSCP is used to mark packet by setting IP precedence bit in IP ToS byte. Packet can be marked by setting layer2 CoS value. A local QoS group value is associated with a packet Cell loss priority bit termed as CLP of ATM header is changed from 0 to 1. IP Precedence and IP DSCP Marking These marking can be used to identify traffic within the network. These marking used to decide how packet should be treated in Weighted Random Early Detection (WRED). First 6 bits of Type of service is used to determine IP DSCP value, Ip precedence value will become a part of DSCP itself, and therefore both the value cannot be set simultaneously. In case if both the value is set simultaneously then IP DSCP value will be the preferred one. IP DSCP preferred over IP precedence as it has more packet marking options but not supported by many whereas IP precedence is likely to support by all devices in network. User can set up to 8 different IP precedence marking and 64 different DSCP marking. Downloaded 4/15/2022 9:44:49 AM Nova Southeastern University IP Address: 137.52.76.29 Quality of Service in SDN Technology CoS Value Marking By matching class of service value, mapping of layer 2 and layer 3 mapping can be configured. Router has to set the value of class of service in case in a packet need to be marked for differentiating QoS service based on different user, where packet leave a router and entering a switch, as switch can only process layer 2 class of service of packet. Thus, we can configured layer 2 and layer 3 mapping by matching class of service value. Maximum of 8 different class of service marking can be set up by user. QoS Group Value Marking To associate a group ID with a packet, packet will be associated with a local QoS group. Based on communit