  For seamless QoS, it is important that all the stakeholders, such as the
hosts, applications, access networks, routers, and other middleboxes, follow a
single protocol and they trust each other. In this article, we investigate the
participation of these entities in providing QoS over wireless networks in
light of DiffServ QoS architecture. We initiate the study by investigating WiFi
and Cellular network traces, which further motivates us a thorough
investigation of these stakeholders with empirical measurements. Our findings
are the followings. (i) Modern mobile VoIP applications request QoS to the
network. (ii) While the operating systems support basic APIs requesting QoS,
application developers either are not aware of such requirements or they misuse
the architecture for improved QoS. (iii) Wireless access networks rewrite the
QoS requirements at the edge and enforce the rest of the routers or hops to
provide best effort service. (iv) QoS requests are also nullified by the secure
tunnels. (v) Although the access networks may nullify the QoS requests, the
performance of the network still may differentiate traffic. We further
emphasize that although the latest 5G network considers DiffServ QoS framework,
it cannot deal with the challenges posed by the privacy related applications.
Network neutrality is going to pose similar challenges.
