IoT Network Layer Protocols
The network layer is divided into two sublayers: routing layer which handles the transfer of packets from source to destination, and an encapsulation layer that forms the packets.
RPL stands for Routing Protocol for Low-Power and Lossy Network. It is a distance-vector protocol that supports a varity of Data Link Protocols. RPL builds a Destination Oriented Directed Acyclic Graph (DODAG) which has only one route from each leaf node to the root. All the traffic in this DODAG is routed through the root. Initially, each node sends a DODAG Information Object (DIO) announcing them self as a root. This information travels in the network, and complete DODAG is gradually built. When a new node wants to join the network, it sends a DODAG Information Solicitation (DIS) request and root responds back with a DAO Acknowledgment (DAO-ACK) confirming the join.
CORPL protocol is the extension of the RPL protocol, which is termed as cognitive RPL. This network protocol is designed for cognitive networks and uses DODAG topology. CORPL protocol makes two new modifications in the RPL protocol. It uses opportunistic forwarding to forward a packet between the nodes. Each node of CORPL protocol keeps the information of forwarding set rather than parents only maintaining it. Each node updates its changes to its neighbor using DIO messages. On the basis of this updated message, each node frequently updates its neighbor for constant forwarder set.
CARP (Channel-Aware Routing Protocol) is a distributed routing protocol. It is designed for underwater communication. It has lightweight packets so that it can be used for Internet of Things (IoT). It performs two different functionalities: network initialization and data forwarding. CARP protocol does not support previously collected data. Hence, it is not beneficial for those IoT or other application where data is changed frequently. The upgradation of CARP is done in E-CARP which overcomes the limitation of CARP. The E-CARP allows the sink node to save previously received sensory data.
The 6LoWPAN protocol refers to IPv6 Low Power Personal Area Network which uses a lightweight IP-based communication to travel over low data rate networks. It has limited processing ability to transfer information wirelessly using an internet protocol. So, it is mainly used for home and building automation. The 6LoWPAN protocol operates only within the 2.4 GHz frequency range with 250 kbps transfer rate. It has a maximum length of 128-bit header packets.
6LowPAN Security Measure
Security is a major issue for 6LowPAN communication Protocol. There are several attacks issues at the security level of 6LoWPAN which aim is to direct destruction of the network. Since it is the combination of two systems, so, there is a possibility of attack from two sides that targets all the layer of the 6LoWPAN stack (Physical layer, Data link layer, Adaptation layer, Network layer, Transport layer, Application layer).
Properties of 6LowPAN protocol