**2. Classification of WSNs protocols**

Routing protocols can be classified into:


*Wireless Sensor Networks (WSNs): Security and Privacy Issues and Solutions DOI: http://dx.doi.org/10.5772/intechopen.84989*


### **2.1 Data-centric routing protocol**

transmissions. As a result of heterogeneity of WSNs' nodes, different protocols had been developed for different WSNs depending on the nature of the nodes and application. For instance, there are dedicated protocols for MWSNs and dedicated

There are two modes of transmission in WSN; single hop involves the source node sending its data packets to the destination within a hop. Meanwhile, WSNs' sensor nodes may rely on one another in order to relay packets to remote destinations. This mode of transmission is called multi-hop. Multi-hop is a routing phenomenon that involves the transfer of data between source and destination nodes with the cooperation of intermediary nodes. It enhances the performance of WSNs by allowing energy-depleted node to transfer data through its neighboring nodes along the routing path to the destination node. There are several security and privacy issues associated with multi-hop routing. Some of these issues like snooping, sinkhole, tampering Sybil, clone, wormhole, spoofing, etc. affect the

Several security solutions had been proposed for WSNs; however, resource constraint of sensors makes some of these security solutions unfit for WSNs. This, therefore, makes their adoption in WSNs impossible. This is as a result of instability of the topology of most WSNs. Some of the WSNs, unlike some other networks, consist of mobile nodes that intermittently change the topology of the networks, therefore making it impossible for such mobile network to use existing protocol developed for static nodes. Also, large volume of data is transferred on the WSNs; this increases the traffic on the wireless communication infrastructure of WSN. All these show that security and privacy solutions of WSN must not only be lightweight in terms of the computational, communication, and energy overheads but also support aggregation and multi-hop in order to reduce the traffics and extend the life span of the networks. Meanwhile, most of the existing security solutions do not

integrity, availability, and data confidentiality of the WSNs.

have these performance requirements [1, 7–10].

**2. Classification of WSNs protocols**

1.Data-centric routing protocol

2.Hierarchical routing protocol

**14**

Routing protocols can be classified into:

protocols for SWSNs.

*A typical wireless sensor networks (WSN) [1].*

*Wireless Mesh Networks - Security, Architectures and Protocols*

**Figure 1.**

Data-centric routing protocol combines data arriving from various sensor nodes at a specific route. This eliminates redundancies and minimizes the total amount of data transmission before forwarding it to the base station. Directed diffusion, rumor routing, and sensor protocol for information via negotiation (SPIN) protocol are examples of data-centric routing protocol [11, 12].

SPIN is a negotiation-based data-centric protocol for WSNs. Each node uses metadata to name its data, and negotiation is performed by a sensor node using its metadata. Hence, each node is able to negotiate whether to deliver data or not, in order to eliminate redundant data transmission throughout the network. After the negotiation, the sender transmits its data as shown in **Figure 2**; node A starts by broadcasting its hop request to its neighboring node B. Once the request is accepted, node A sends its data to B who then repeats this procedure. This is to find its neighboring node and hops the data to the neighboring node until the data reaches the destination. SPIN protocol saves energy due to the fact that each node only performs single hop. SPIN's hop request and acceptance packets prevent flooding attack on WSNs. Although SPIN protocol is good for lossless networks, it can also be used for lossy or mobile networks.

### **2.2 Hierarchical routing protocol**

Hierarchical routing protocol classifies network nodes into hierarchical clusters. For each of the clusters, the protocol selects a node with high residual energy as the cluster head. The sensed data of each node in the cluster are transferred through the cluster heads of the clusters in the network [11]. The cluster node aggregates the sensed data of all the nodes in the cluster before sending it to the sink. Hierarchical routing protocol reduces the energy consumption through multi-hop transmission mode [13]. Also, data aggregation performed by the cluster head reduces traffic on

**Figure 2.** *SPIN protocol.*

the network. Low-energy adaptive clustering hierarchy (LEACH), thresholdsensitive energy-efficient sensor network protocol (TEEN) and adaptive threshold-sensitive energy-efficient sensor network protocol (APTEEN), and secure hierarchical energy-efficient routing (SHEER) are examples of hierarchical routing protocol. TEEN gives a very good performance since it reduces the number of transmissions [14]. Patil et al. presented SHEER in [15]. It uses adaptive probabilistic transmission mechanism for determining the optimal route in WSN. SHEER also adopts hierarchical key establishment scheme (HIKES) for key distribution, authentication, and confidentiality. SHEER involves four phases as described below:

*2.3.1 Disjoint path routing protocol*

*DOI: http://dx.doi.org/10.5772/intechopen.84989*

*2.3.2 Braided path routing protocol*

almost equal [17].

(GLAR), etc.

**17**

is reliable with extra overhead but at a low energy.

*2.3.3 N to 1 multipath discovery routing protocol*

reduces congestion, and effectively manages.

**2.5 Quality of service (QoS)-based routing protocol**

QoS-based routing protocols are described below:

*2.5.1 Sequential assignment outing (SAR) protocol*

**2.4 Location-based routing protocol**

In a disjoint path routing protocol, every source node finds the shortest disjointed multipath to the sink node. It evenly shares its data load among these disjointed paths. All the paths in this multipath share no sensor node. The protocol

*Wireless Sensor Networks (WSNs): Security and Privacy Issues and Solutions*

To construct braided multipath, the protocol first selects the primary path; then for every sensor, the best path is chosen from source to sink node, but this path does not include the primary node. The best alternative paths that are not necessarily disjoint from the primary path are called idealized braided multipath. These alternative paths are located either on the primary path or very close to it which means that the energy consumption on both the primary path and an alternative path is

N to 1 multipath discovery protocol is a protocol based on flooding. Example of N to 1 multipath-based routing protocol is multipath-based segment-by-segment routing (MSSR) protocol proposed by Lu et al. in [18]. MSSR protocol divides a single path into multiple segments, where multiple node-disjoint paths are discovered and independently maintained. N to 1 multipath discovery routing protocol

Location-based routing protocol routes data based on the distance of the source and destination nodes. It calculates the distance between source and destination nodes in order to determine estimated routing energy. Shruti [19] proposed a location-based routing protocol. The protocol uses the signal strength of the incoming signal to determine their distance. In their protocol, all the non-active nodes are put in sleeping mode in order to save energy. In location-based, the knowledge of the position of sensor nodes is exploited to route the query from the base station to the event. Location information enables the network to select the best route. Another example of the location-based protocol is the geographic adaptive fidelity (GAF) protocol for mobile adhoc networks (MANETs). GAF conserves energy, and reduces routing overhead, which makes suitable for WSNs. Other examples of location-based protocols are location-aided routing (LAR), energyefficient location-aided routing (EELAR), greedy location-aided routing protocol

QoS-based routing protocol balances effective data delivery of the data to the sink node with some predetermined QoS metrics [17, 20]. Some of the existing

SAR protocol uses energy, QoS on each path, and the priority level of each packet as the QoS metrics to achieve effective data delivery. SAR protocol discovers
