TL;DR: Reporting on IPv4 measurements regarding the DSCP field and the Evil bit confirms recent results on IP Options and ECN and contributes to the body of work that tries to answer these questions.
Abstract: The IP header should be the ideal part of a packet that an end system could use to ask the network for special treatment. Recently, there has been renewed interest in using bits of this header -- e.g. the ECN and the DSCP fields. But can we really use these bits? Or should we try to use other bits? We contribute to the body of work that tries to answer these questions by reporting on IPv4 measurements regarding the DSCP field and the Evil bit. Our findings also confirm recent results on IP Options and ECN.