Radio Access Network (RAN) are likely to be overloaded, and some places will not be able to provide the necessary requested bandwidth. In order to respond to the demand of bandwidth, overloaded RAN are currently offloading their traffic on WLAN. WLAN Access Points like (ISP provided xDSL boxes) are untrusted, unreliable and do not handle mobility. As a result, mobility, multihoming, and security cannot be handled by the network anymore, and must be handled by the terminal. This paper positions offload architectures based on IPsec and shows that IPsec can provide end-to-end security, as well as seamless connectivity across IP networks. Then, the remaining of the paper evaluates how mobility on these IPsec based architectures impacts the Quality of Service (QoS) for real time applications such as an audio streaming service. QoS is measured using network interruption time and POLQA. Measurements compare TCP/HLS and UDP/RTSP over various IPsec configurations.