Dynamic Routing Framework for Wireless Sensor Networks [chapter]

Mukundan Venkataraman, Mainak Chatterjee, Kevin Kwiat
2010 Sustainable Wireless Sensor Networks  
Numerous routing protocols have been proposed for wireless sensor networks. Each such protocol carries with it a set of assumptions about the traffic type that it caters to, and hence has limited interoperability. Also, most protocols are validated over workloads which only form a fraction of an actual deployment's requirement. Most real world and commercial deployments, however, would generate multiple traffic types simultaneously throughout the lifetime of the network. For example, most
more » ... example, most deployments would want all of the following to happen concurrently from the network: periodic reliable sense and disseminate, real time streams, patched updates, network reprogramming, query-response dialogs, mission critical alerts and so on. Naturally, no one routing protocol can completely cater to all of a deployments requirements. This chapter presents a routing framework that captures the communication intent of an application by using just three bits. The traditional routing layer is replaced with a collection of routing components that can cater to various communication patterns. The framework dynamically switches routing component for every packet in question. Data structure requirements of component protocols are regularized, and core protocol features are distilled to build a highly composable collection of routing modules. This creates a framework for developing, testing, integrating, and validating protocols that are highly portable from one deployment to another. Communication patterns can be easily described to lower layer protocols using this framework. One such real world application scenario is also investigated: that of predictive maintenance (PdM). The requirements of a large scale PdM are used to generate a fairly complete and realistic traffic workload to drive an evaluation of such a framework. balanced communication, aggregation centric approaches (19) and so on to name a few. Each such protocol typically optimizes a certain set of chosen parameters in making routing decisions, and is likewise validated over a workload that only generates that type of network traffic. This means that a deployment that adopts any given protocol has to build its entire deployment logic using the traffic type for which the protocol is optimized. To make sensornets a viable solution to real world problems, applications need to be built on top of arbitrary communication patterns, often with conflicting requirements. For example, a meaningful case of habitat monitoring would mostly demand all of the following communication patterns to co-exist: periodic network reports using reliable sense and disseminate, critical real time alerts when anomaly is detected, aggregation to suppress duplicates, network reprogramming to transfer bulk data, patched updates for continuous customization of the sensornet, best effort communication to transfer redundant information, interactivity with the network in the form of request-reply dialogs and so on. Naturally, no one routing protocol can cater to such varied application requirements within a given deployment. In other words, a given deployment can be viewed as a collection of various tasks (applications) which have very different, and often conflicting, communication requirements. The deployment goal is met when the goals of its constituent applications are fulfilled. Secondly, there is little synergy across research efforts. Pressed by scarcity of energy and a need to focus on performance, protocols are developed with little thoughts to modularity and interoperability. Though a new application deployment would have a plethora of routing protocols to choose from, these protocols cannot be readily wired together to form a communicating framework due to compatibility problems. Compatibility problems largely arise because of the assumptions made on interface and data structure requirements. In general, and as Culler et. at. (5) note, a framework for testing, integrating and proposing protocols is largely missing. This chapter presents a routing framework that makes an application's communication requirements visible to the lower layers, and allows activation of application specific processing. The traditional routing layer is replaced by a highly composable collection of routing decisions. Now, the routing logic is dynamically wired as per each packets requirements. The effectiveness of this strategy is demonstrated by gathering requirements and validating a fairly complete deployment scenario: predictive maintenance (PdM) using sensornets (15). Protocol Description Routing Framework Overview Application payload presents a three bit preamble to the framework that describes it communication intent, The framework dynamically switches routing decisions based on the preamble bits. The routing layer is now a composable set of routing components that perform similar functions, but are optimized for different classes of traffic. The routing components carry a similar three bit signature that lets the framework know their applicability for a certain class of traffic. The selection of a routing component is hence a mapping between what the application demands and what the component has to offer. The routing components house core protocol features that cater to a particular application type. This allows components to evolve independently, and owing to their composable nature, allows seamless migration from one deployment experience to another. To unify interface assumptions, the routing components
doi:10.5772/13495 fatcat:jzkl2icuojabvmhc2iubbd7dly