Wireless Sensor Networks (WSNs) are becoming increasingly important because of their reduced cost and a range of real world military applications. IP connectivity to WSNs has enabled ubiquity of devices. IPv6 based Wireless Personal Area Networks (6LoWPANs) are the realization of these IP based Ubiquitous Sensor Networks (IP-USNs). Management of such low power and constrained networks is a crucial problem. In this thesis I propose LoWPAN Network Management Protocol (LNMP) which is the management architecture for 6LoWPAN based WSNs. We present operational and informational architectures for 6LoWPAN. Moreover, we also propose the design of the management information base for the management of such networks