Recent advances in electronics and integrated circuits have fostered the development of Wireless Body Area Networks (WBANs) as a key technology to provide ubiquitous healthcare monitoring services to patients. The specificities of the operating environment and treated data make WBANs unique compared to other networks. Consequently, IEEE 802 organization has established a Task Group called TG6 for the standardization of WBANs. The TG6 group has defined the IEEE 802.15.6 standard or precisely a Physical (PHY) and Medium Access Control (MAC) WBAN Layers. Also, the TG6 stated that two logical management entities that exchange network management information with the defined PHY and MAC layers as well as with other layers have to be designed. This paper presents a Node Management Entity (NME) and a Hub Management Entity (HME) architectures based on IEEE 802.15.6 standard. Our proposed HME and NME architectures combine cross and modular design architecture to ensure network reliability and enhance the WBAN Quality of Service (QoS).