Routing can optimize network performance such as delivery ratio, delivery delay, and overhead. In other words, routing determines the sequence of transmitting nodes and the number of packets...

Routing Protocols in WSN
Contents
Introduction    2
Motivation    2
Routing Protocol Analysis    3
Sensor Protocol for Information via Negotiation (SPIN)    3
Directed Diffusion    4
Advantages    4
Limitations    6
Incorporation of Feedback    6
Attacks against Routing Protocols    7
Countermeasures    8
Comparative Analysis    9
Conclusion    10
References    10
Introduction
This paper focuses on discussing two routing protocols for wireless sensor networks (WSN). A wireless network is formed using multiple small sensors. Such a network is a self- organized infrastructure-less wireless network that monitors environmental conditions on its own and transmit data in a synchronized manner to main location called sink which analyses the data. Sink addresses the queries generated by users by collecting results and providing required information. Sensor protocol for information via negotiation (SPIN) and directed diffusion are two protocols discussed in this paper which allow exchange of data effectively over a WSN. The mechanism of these protocols is discussed in the initial sections along with their advantages and limitations. The subsequent sections highlight the security threats to which these protocols are vulnerable and the countermeasures that can prevent or detect the attacks on these protocols. A comparative analysis is done on the two protocols depicting the usage and benefit of one routing protocol over the other.
Motivation
Routing protocols play an important role in producing efficient and interruption less communication within the nodes of the WSN. Applications using WSN demand quick data transmission with minimum interruption. The service, performance and reliability of the WSN depends on the choice of its routing protocol. Therefore, a comparative analysis of the routing protocols is crucial before selecting it for the network.
Routing Protocol Analysis
Sensor Protocol for Information via Negotiation (SPIN)
This routing protocol is basically for exchanging data about the sensor data in network operation. It is a negotiation-based information dissemination protocol based on meta data [1]. Sensor applications can communicate about the data that is already possessed and the one required. Data negotiation and data adaptive algorithms are used. The nodes can increase the system’s utility time by monitoring and adapting to changes through SPIN. The mechanism uses three kinds of messages:
· ADV- The SPIN node advertises that it has data for sharing using ADV message with meta-data.
· REQ- SPIN node sends this message to receive data.
· DATA- These messages contain sensor data along with meta-data header.
REQ
ADV
ADV
1
2
3
4
5
ADV
DATA
ADV
Figure: SPIN Routing Protocol
DATA messages are larger than ADV and REQ as the latter contain only meta data. A SPIN peer-to-peer protocol works in three stages. The protocol begins by advertising that it has data available for dissemination through ADV message. The neighboring node receives ADV and checks if it has requested or received the advertised data. It sends REQ to request for missing data to the former node. The sender responds to the REQ with DATA thus completing the protocol.
Directed Diffusion
This protocol for WSN is a data centric query-based protocol where sink floods a query into the network through several routes between the sink and source. The sink supports one of those routes and receives data from that path within shorter time interval. Therefore, multipath delivery can be realized and significant achievement can be attained by adapting subset of network.
The four features of directed diffusion routing protocol include Interests, data, gradients and reinforcement. The query that determines the user’s requirements is the Interest. Processed information is the data. The direction state of node that gets the Interest is the gradient. Multiple gradient paths are used to transmit events from originators of interest. The attribute value pairs that are used to name task descriptions are
example:     type=wheeled vehicle        //vehicle location
        interval=20 ms        //event sent every 20ms
        duration=10s            //next 10s duration
        rect=[-100,100,200,400]    // sensors inside rectangle
Advantages
The advantages of SPIN routing protocol include
· The SPIN protocols achieve high level performance with respect to computation, complexity, communication and energy.
· Each node in SPIN requires to know its single-hop neighboring node thus allowing localized topological changes.
· The redundant data is halved through meta data...