Exploring DSCP modification pathologies in mobile edge networks

Differentiated Services (DiffServ) provides a means for applications to classify traffic into Quality of Service (QoS) classes by reading the Differentiated Services Code Point (DSCP) field in the IP header and then mapping traffic to a specific QoS forwarding treatment. This paper provides new measurement data that examines how the DSCP is altered as packets traverse mobile broadband access networks. Results are presented for entire paths, differentiating between the access network behaviour and the rest of the path. Observing the DSCP seen at each router can be used to infer whether a packet is likely to receive an appropriate QoS treatment, and hence the level of support for DiffServ QoS. Our results identify two remarking pathologies, one for the mobile networks and the other for the Internet path.