In this paper, we evaluate performance of 6LoWPAN and PANA over a mesh network based on mathematical analysis, considering IEEE 802.15.4 MAC/PHY behavior, 6LoWPAN behavior including fragmentation and PANA protocol behavior. End-to-end IP packet error rate, mean end-to-end IP packet delay, PANA session failure rate and mean PANA session establishment delay are used as the performance criteria. We show tradeoff points between Long Frame and Short Frame profiles for 6LoWPAN and PANA performance. As a result of performance analysis, we show a recommended PANA profile for IEEE 802.15.4g mesh networks to use Long Frame profile as long as MAC performance metric meet certain criterion.