IP TOS bits value, defined as all eight bits of the Service Type octet in the IPv4 header. There are multiple, overlapping, meanings of the TOS octet in use today: Precedence (bits 7-5): IP Precedence, values 0-7 DSCP (bits 7-2): IP DiffServ Code Point, values 0-63 TOS (bits 7-0): IP Type of Service, by bits, values 0-255 Each of these definitions can be produced using the appropriate agentDiffServAuxMfClfrTosMask mask value. These definitions are mutually-exclusive, so only one is allowed for any given classifier element.