Implementation of 6LoWPAN Border Router (6BR) in Internet of Things

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1 Implementation of 6LoWPAN Border Router (6BR) in Internet of Things Mrs. Snehal Deshmukh-Bhosale, Research Scholar, Raisoni College of Engg. & Management, Wagholi Asst. Professor, RMD Sinhgad School of Engg, Warje, Pune Dr. S. S. Sonavane, Director, Dr. D. Y. Patil Technical campus, Lohgaon ABSTRACT: Future internet will be formed with IPv6 protocol which can connect 2 smart objects and networks with traditional computers. This terminology is called as Internet of Things (IoT). IoT is formed by devices constrained in terms of battery power, processing, memory etc. For functionality of these devices a low power networking protocol is required and this requirement is solved by 6LoWPAN (IPv6 Low Power Wireless Private Area Network)protocol. This protocol takes care of compatibility between IPv6 and IEEE protocols. 6LoWPAN uses an adaption layer between the network (IPv6) and data link layer (IEEE MAC) to fragment and reassemble IPv6 packets. The routing in 6LoWPAN is primarily divided on the basis of routing decision taken on adaption layer.. In IoT devices are connected to internet through the router which is known as 6LoWPAN Border Router (6LBR). 6LBR acts as a gateway in IoT which connects 6loWPAN devices to internet. In this paper we will discuss details of 6LBR and its implementation in open source operating system Contiki and Cooja Simulator. KEYWORDS-IPv6, 6LOWPAN, 6LBR, Routing. 1. INTRODUCTION In IoT WSN nodes are connected to existing IP based network using 6LoWPANs. There are many non IP network protocols in Wireless Sensor Network (WSN) such as Zigbee which doesn t support TCP/IP protocol suite. 6LoWPAN is placed below network layer and above Mac layer forming Adaptation Layer as shown in Fig. 1. Fig 1. IoT Protocol Suite 269 Snehal Deshmukh-Bhosale, Dr. S. S. Sonavane

2 The function of adaptation layer is to build a compatibility between IPv6 and IEEE protocol with fragmentation and reassembly of packets. The main function of routing protocol is to maintain the routing table which contains the information of path through which packets to be transmitted by considering hop count as metric. As IoT contains resource constrained devices in terms of memory, processing power, bandwidth, energy etc it is necessary to reduce bandwidth utilization, processing requirement and packet overhead. These requirements are achieved by 6LoWPAN network. In this network to take care of network interconnection, coordination, address configuration a concept of 6LoWPAN Border Router ( 6LBR) has come in picture. IoT is formed by internetworking of smart objects connected to each other using IEEE protocol. This network is connected to IP network with the help of 6LBR. 6LoWPAN is developed for constrained devices which used compressed header format when IPv6 packets travel on network. The function of 6LBR is to compress and decompress IP packet headers to transmit the packets from nodes to internet and vice versa.a true end-to-end secure communication between smart objects and Internet hosts is illustrated in Figure 1. This network deployment needs to have secure communication. IPv6 supports IPsec, which is default mechanism for security for IPv6 based networks. [1] Fig. 1 communication between sensor nodes in 6LoWPANs and hosts in an IPv6-enabled Internet 2. ARCHITECTURE OF 6LBR IoT is formed by large range of technologies which always go through interoperability problem. All the systems in IoT are heterogeneous and no common protocol is used ti integrate these devices. In IoT 6LoWPAN is based on IP standard. When in IoT, two IP protocol based networks are connected to each other, no proxy or gateway is required in such case. 6BR is required when two different types of networks in terms of connectivity protocols are connected in IPv6 based network. As shown in fig. 2 6LBR is placed between access point of WSN and internet. Packets from nodes are transmitted to internet through 6LBR. 6LBR is responsible to convert IPv6 packets to 6LoWPAN format and then transmitted to internet. Same process is repeated for opposite side communication. 6LBR contains: i. IPv6 for node ID ii. 6LoWPAN stack for communication between node and cloud. iii. NAT64 for internet operability with nodes Architecture of 6LBR is shown in Figure 2 [2] Figure 2: General architecture for 6LBR 270 Snehal Deshmukh-Bhosale, Dr. S. S. Sonavane

3 2.1 Roles of the Border Router Forwarding between IPv6 and 6LoWPAN IP configuration of the nodes (6LoWPAN-ND) Multihop routing (RPL) Context sharing [3] 3. ROUTING IN 6LOWPAN Routing is one of the main task of the network layer as defined by the Open System Interconnection (OSI) model. Various other tasks include addressing of nodes and creation and maintenance of network topology. 6LoWPAN technology adopts the modified IPv6 protocol stack to achieve seamless connectivity between IEEE based networks and the IPv6 based infrastructure. Based on the application, 6LoWPAN routing protocols can be classified into Mesh-under routing and Routeover routing as illustrated in Figure 3. [4], [5] 3.1 Mesh-under In mesh-under routing, both the Extended Universal Identifier (EUI)-64 bit and 16 bit addressing schemes are used to send a packet to a particular destination through the neighbouring nodes (Zach Shelby and Carsten Bormann, 2009). 6LoWPAN header consists of both the link layer originator and the final destination address. Multiple link layer hops are used to complete a single IP hop and hence it is called mesh-under. The adaptation layer divides the IP packet into number of fragments and these fragments are delivered to the destination in a hop by hop manner using mesh routing. The divided fragments take different paths to reach the destination and they are gathered together at the destination. After all the fragments reach the destination, the adaptation layer of the destination node reassembles all the fragments and creates an IP packet. If any fragment is missed during the forwarding process, the entire IP packet is transmitted to the destination. In mesh-under approach, no IP routing is done within the LoWPAN. In this approach, forwarding of data is performed at the link layer based on the IEEE frame. 3.2 Route-over In Route-over, the decision of routing is taken at the network layer. Here each 6LoWPAN node in the network acts as an IP router. In this approach, each link layer hop is an IP hop by which packets are forwarded in the network. The routing process in the network layer uses the encapsulated IP header and routing tables. IPv6 packets are divided into IP packet fragments and forwarded. After all the IP fragments reach the destination, the adaptation layer reassembles the IP packet and sends it to the network layer. If the IP packet reaches the destination, the network layer sends the IP packet to the transport layer, otherwise it forwards the packet to the next hop based on the routing table information. Therefore route-over approach performs IP routing. IP address is generated with a combination of IPv6 prefix and interface identifier acquired through Stateless Address Auto configuration (SAA). [6] (a) Mesh Under (b) Route Over Fig 3: Mesh Under and Route Over Forwarding 271 Snehal Deshmukh-Bhosale, Dr. S. S. Sonavane

4 3.3 Characteristics of 6LOWPAN Routing 6LoWPAN routers perform forwarding on a single wireless interface. They send and receive the information between nodes using the same interface. A 6LoWPAN has a flat address space, as all nodes in a LoWPAN share the same IPv6 prefix. 6LoWPANs are stub networks, and are not meant to be transit networks between two different subnets, which simplifies the requirements for 6LoWPAN routers. [7] 4. PROPOSED ALGORITHM AND IMPLEMENTATION OF 6LBR For the designing of 6LBR we use Contiki OS 2.7. This provide introduction of Border router in Contiki OS. Border router is connected to internet when the other sensor nodes are reporting the data via the border router (Ref Fig 1). Implementation of this router is giving by all IOT operating systems. The RPL border router is used in order to interface a regular IP network with an RPL 6LoWPAN network. This is similar to the bridge that was previously used, except that it also runs an RPL network. The border router is located in the contiki- 2.6/examples/ipv6/rpl-border-router folder. We have used sky motes for functioning of the nodes. After running the simulation we can see network as shown in Fig.4 We can access these nodes IP address in browser and see the sensor out as in Fig. 5 [8],[9]. Fig 4 Installation of Border Router in Cooja Simulator Fig 5. Light and Temperature sensor reading through proposed system 272 Snehal Deshmukh-Bhosale, Dr. S. S. Sonavane

5 5. CONCLUSION In this paper we have studied the theory of 6LOWPAN Border Router concept and implementation techniques. Mesh under and route over routing schemes in 6LoWPAN are studied thoroughly. Different deployment modes of 6LBR like Smart Bridge Mode Router Mode Transparent Bridge Mode are studied. We have developed a network with skymote node and 6LBR and checked the functionality of the system. We developed a simulation that extends the current routing functionality found in the Contiki operating system and implemented it in a working model that can be directly attached to an Ethernet segment. Our border router might be used to easily build meshed WPANs that can incorporate a large number of smart objects within a geographic area and make them universally reachable. 6. REFERENCES: [1] Ms. Snehal Deshmukh, Dr. S. S. Sonavane, Security Protocols for Internet of Things: A Survey, ICNETS2, VIT University, Chennai, 2017, /17/$31.00_c 2017 IEEE. [2] Shahid Raza, Shahid, LinusWallgren, and Thiemo Voigt. "SVELTE: Real-time intrusion detection in TheInternet of Things."Ad hoc networks 11.8 (2013): [3] Jorge Granjal, Edmundo Monteiro, Jorge Sá Silva Security for the Internet of Things: A Survey of Existing Protocols and Open Research issues,university of Coimbra, Portugal.IEEE Communications Surveys & Tutorials DOI /COMST [4] Shahid Raza, Simon Duquennoy, Tony Chung, Dogan Yazar Thiemo Voigt and Utz Roedig, Securing Communication in 6LoWPAN with Compressed IPsec, /11/2011 IEEE. [5] Mr. Tejas Mehare, Prof. Mrs. Snehal Bhosale, Development of 6LoWPAN Border Router for Secure Communication, International Journal of Advanced Research in Computer and Communication Engineering, Vol. 6, Issue 3, March 2017 [6] Praveen Kumar Kamma, Chennakeshava Reddy Palla, Usha Rani Nelakuditi, Ravi Sekhar Yarrabothu. "Design and implementation of 6LoWPAN border router", 2016 Thirteenth International Conference on Wireless and Optical Communications [7] Jorge Granjal, EdmundoMonteiro, Jorge SáSilva, Enabling network-layer security on IPv6Wireless Sensor Networks, /10/$ IEEE [8] Praveen Kumar Kamma, Chennakeshava Reddy Palla, Usha Rani Nelakuditi, Ravi SekharYarrabothu, Design and Implementation of 6LoWPANBorder Router, /16/$ IEEE [9] Wei Ge1, Lin Zheng, Peng Luo1, Zhenghong Liu, Implementation Of Multiple Border Routers For 6lowpan With Contikios, 273 Snehal Deshmukh-Bhosale, Dr. S. S. Sonavane