perception layer of IoT which is at lowest level is identical to OSI model’s physical layer. The main job of perception layer is to recognize the physical properties of IoT objects.

It basically gathers information from the surrounding world and processes this messed information. The processed information is then transmitted to the above layer i.e. network layer.Network Layer: The middle layer of IoT architecture is network layer which receives processed information from the perception layer. Network layer determines the route of the sensor data to different devices over the internet. Devices like hub, routing devices, gateways, switching, cloud computing etc. operate using various communication technologies like Wi-Fi, Bluetooth, Zigbee, LTE etc.

Using these communication technologies network layer transmits data to different applications in heterogeneous network. It also handles congestion in occurs between nodes. Application Layer: The topmost layer of IoT architecture is application layer, which obtains data from network layer. Application layer delivers application services to the users. The job of application layer is to create smart application environments like smart health, smart homes, smart transportation etc.Communication Technologies: IoT is well smart enough system, interconnects things in such a way that communication occurs and that technology is known as machine-to-machine (M2M) communication, which is basically a way of communication among IoT devices in large heterogeneous network without the interference of human beings. It is predicted that billions of IoT devices will be connected all over the world by the year 2021, and maximum number of connected devices will be through M2M communication 4.

Various communication technologies are there to connect these large number of devices, there are mainly two categories first is short range communication technology includes RFID (Radio Frequency Identification), ZigBee, (BLE) Bluetooth Low Energy, (NFC) Near Field Communication, (6LoWPAN) over Low power Wireless Personal Area Networks and Z-Wave and second one is long range communication technology includes Cellular and SigFox are Low Power WAN’s.RFID: RFID is Radio Frequency Identification, it is a noncontact communication technology, used to recognize and trace objects without any contact 5. It is used for short distances and supports the exchange of data via radio waves 6, 7.

In RFID systems there are two parts, one is reader which is a reading device, and the other is RF tag which is a small radio frequency transponder 8. The RF tag contains unique information that has a distance reading feature 8. The RFID tags have two technologies: the first technology is active reader tag and the second technology is passive reader tag. Active reader tags are costly, battery driven and use higher frequencies, while the passive reader tag do not have internal power source and use lower frequencies 8.

6LoWPAN: 6loWPAN is IPv6 over low-power wireless personal-area networks. It is an IP-based standard internetworking protocol that is most commonly used communication protocol in IoT. Without the intervention of proxies and gateways it can be connected to other IP networks. 6LoWPAN standard is defined by the Internet Engineering Task Force (IETF).

The advantages of 6LoWPAN are small packet sizes, low power (supports low power devices), lower bandwidth, great compatibility and connectivity, ad-hoc self-organization etc.) 9. IoT applications which involve many low cost as well as low power devices can be built using 6LoWPAN.

ZigBee: Zigbee is an IEEE 802.15.4 standard protocol used for wireless communication. It is used to transmit data for longer distances like in personal area networks (PAN’s), digital radios where power consumption is low etc.

Zigbee is best suited to IoT applications that demands long power backup, security, lower data rates etc. 8. Network topologies supported by Zigbee are tree, star and mesh 11 12.BLE: BLE stands for Bluetooth low energy; it is a communication protocol mainly used for IoT applications where there is energy consumption is very low.

Apart from this BLE is also used for IoT applications that require communication for short distances, low latency and low bandwidth 8. A large number of nodes can be connected using star topology and this setup takes very less installation time 11 12. There is no need of pairing; BLE provides a simple mechanism for node discovery for data transmissions over short distances 13.NFC: NFC is Near Field Communication as its name suggests used for short exchanges of data. It is a standard communication protocol for mobile electronic devices like smart phones for setting up connections over very short distances (in centimeters) 14. NFC is a form of communication used in contactless devices and provides the facility of secure mobile payments by linking a debit/credit card to your device. The process of transferring files can be done using NFC which involves simple and easier steps of allowing, pairing and setting up a connection between devices.

The use of NFC is limited to faster data transfer over few centimeter distances, for longer distances we have other communication technologies. Z-Wave: Z-wave is a wireless communication technology mainly used for home automation (smart locks, smart wearable’s, smart doors and windows, smart swimming pools, smart sensor control etc.) systems in internet of things 15. It is simple, cheap, reliable and low power consumption technology 15. If we consider two factors i.

e. low power and longer distances then Z-wave is best alternative to Wi-Fi and Bluetooth. Z-wave communication technology uses mesh topology to connect large number of nodes in a network, large number of nodes leads to high reliability. In home automation systems there is one single controller that can control home area networks 16 17. As Z-wave has wider popularity in home automation system, it can also have other large market opportunities in internet of things.II. LITERATURE SURVEY ON SECURITY ATTACKS AND ITS COUNTERMEASURESIoT is a smart technology, in daily life it involves a tremendous amount of data transfer among heterogeneous devices and data sharing as well.

Such environments need a security and privacy mechanisms. Firstly this section will cover the types of attacks on IoT devices and in rest of the section will talk about the security mechanisms to control such kinds of attacks. Security and privacy measures used in