The source DESCRIPTION for this object is empty; based on its role as the index of teraIpClassTable, it identifies which IP-header field, such as protocol, TOS, or DSCP, a given traffic-classification entry is defined against. Admins would use it, together with the other columns in this row, to see which specific packet field this classification rule matches on when building or auditing a class-of-service policy. As an illustrative example, a value here might identify the DSCP field so the accompanying teraIpClassValue can specify a particular DSCP codepoint to match.