1-6IP Precedence (decimal) IP Precedence (binary) Description2 010 immediate3 011 flash4 100 flash-override5 101 critical6 110 internet7 111 networkIn a network providing differentiated services, traffics are grouped into the following fourclasses, and packets are processed according to their DSCP values.z Expedited Forwarding (EF) class: In this class, packets can be forwarded regardless oflink share of other traffic. The class is suitable for preferential services with low delay,low packet loss ratio, low jitter, and assured bandwidth (such as virtual leased line);z Assured forwarding (AF) class: This class is further divided into four subclasses(AF1/2/3/4) and a subclass is further divided into three drop priorities, so the AFservice level can be segmented. The QoS rank of the AF class is lower than that of theEF class;z Class selector (CS) class: This class comes from the IP ToS field and includes eightsubclasses;z Best Effort (BE) class: This class is a special class without any assurance in the CSclass. The AF class can be degraded to the BE class if it exceeds the limit. Current IPnetwork traffic belongs to this class by default.Table 1-3 Description on DSCP precedence valuesDSCP value (decimal) DSCP value (binary) Description46 101110 ef10 001010 af1112 001100 af1214 001110 af1318 010010 af2120 010100 af2222 010110 af2326 011010 af3128 011100 af3230 011110 af3334 100010 af4136 100100 af4238 100110 af43
