Congestion exposure in mobility scenarios

Congestion-based policing is a promising network resource control paradigm, for accounting user traffic based on resource congestion rather than resource usage. Congestion Exposure (Conex) is such an approach, where a user is expected to declare its congestion contributions back to the network. Since congestion is changing with offered load, the end-host transport protocols adjust response to changing path characteristics. For incorporating congestion exposure into mobile networks, the end-host should also take path changes into account. In this paper we evaluate issues of mobility on the feedback loop especially under network controlled mobility scenarios. While introducing path changes, the fundamental issue for an operator is the traffic differentiation between compliant and non-compliant sending hosts. In contrast, while shifting between different congestion regions, the prime issue for an end point is controlling the declared congestion that should minimize the deficit close to the receiving host. This paper we use the specific Re-ECN implementation as a specific example of congestion exposure, one proposal among several. So the paper evaluates Re-ECN under mobility, where mobility is emulated through OpenFlow in our testbed.