Experiments and analysis of voice over mobile IP

Supporting mobility in real-time applications such as Internet telephony is in demand as mobile Internet becomes prevalent. A simple solution is to use Mobile IP in order to provide transparent handoffs to upper layer applications. However, due in part to the Mobile IP's limitations such as triangular routing delay and encapsulation overhead, application-layer solutions for mobile Internet telephony has been developed by extending Session Initiation Protocol (SIP). This work presents experimental results on Internet telephony based on Mobile IP and examines its feasibility by analyzing delay factors and increased network loads. We found that packet size in terms of number of frames per packet is important in optimizing the packet transmission delay and network load without hindering the interactivity in voice conversations. Our major contribution is to give a real experience on voice over Mobile IP and to raise a need of designing delay-aware and/or load-aware scheme for Internet telephony.