## 5 Discussion and Open Research Issues
### Analysis of I2O WBAN Based Health IoT  
An effective approach for the interconnection of WBAN systems is to use the Internet Protocol (IP) [35]. WBAN information packets can be processed and translated into IP datagrams by a gateway or a smartphone on various available platforms, such as the Advanced Health and Disaster Aid Network (AID-N) and the Microsystems Platform for Mobile Services and Applications (MIMOSA) [20]. Smartphones equipped with multiple network interfaces could enable the user to interact with the linked WBAN and forward data to physicians in any location [35; 50].  
To date, the core of health IoT solutions is low power, wireless personal area networks (6 LoWPAN) and Internet Protocol for Smart Objects (IPSO), which are predicted by the Internet Engineering Task Force (IETF) and aim to manage WBAN devices Internet connectivity issues through IP version 6 (IPv6) [35]. It is of great significance that the I2O WBAN infrastructure supports access to the health IoT. Meanwhile, more effort should be spent on I2O WBANs low power consumption routing protocol design in order to minimize the energy consumption and improve multiple QoS metric performance. An I2O WBAN sensor address configuration process should consider uniqueness, low energy consumption and offer address reclamation. Once a WBAN system collects the physical parameters of a human body, all sensor nodes in the WBAN must be configured with a unique address [48]. In recent years, the IEEE and other authorities have standardized numerous protocols to support WBANs [20]. However at present, the proposed standardized protocols are ineligible foran I2O WBAN [20; 35; 51]. For example, the IEEE 802.15.3 standard is designed for high data speed, wireless personal area networks (WPANs) that can reach up to 20 Mbps. However, this standard does not support energy efficiency and other QoS requirements [35]. The IEEE 802.15.4 standard is considered as an energy efficient protocol but only capable for low data rate applications and services [35]. The latest IEEE 802.15.6 defines MAC and PHY layers for low-power consumption implant devices, whereas the security requirements of data authentication and encryption have not been well defined [20]. The Zigbee IP is the first open standard for the IPv6 standard, which enriches the WBAN services by adding network and security layers. However, recently, the Zigbee Alliance decided to incorporate standards from IETF into its technical specifications [20].  
I2O WBANs can be divided into two categories; (1) every sensor node is provided with a unique entity or; (2) the network is an entity and accessible via a coordinator node that has full information about the network [50]. I2O WBAN sensor nodes are attached on, or within the human body area to process sensed data with wireless transfer to a coordinator connected to the internet [3]. Considering QoS-aware requirements, this paper presents a potential QoS-aware protocol design for I2O WBAN with the following characteristics:  
1. The I2O WBAN consists of at least one full function device (such as a smartphone) and a series of reduced function small-size sensor nodes, which are assigned a unique ID.
2. Each sensor node senses different physical parameters to reduce the address configuration cost.
3. A relay strategy is considered, which decreases system configuration delays and minimizes the overall length of communication distance within I2O WBAN.