construction: Optimizing the node locations during the deployment phase Change the transmission range of the nodes Turn off nodes from the network Create a communication backbone Clustering Adding new nodes to the network to preserve connectivity (Federated Wireless sensor networks) Some examples of topology construction algorithms are: Tx range-based Geometry-based: Gabriel graph (GG), Relative neighborhood graph (RNG), Voronoi diagram Spanning Tree Based: LMST, iMST Direction Based: Yao graph and Nearest neighbor graph, Cone Based Topology Control (CBTC), Distributed RNG Neighbor based: KNeigh, XTC Routing based: COMPOW Hierarchical CDS-based: A3, EECDS, CDS-Rule K Cluster-based: Low Energy Adaptive Clustering Hierarchy (LEACH), HEED Graphical examples Topology maintenance algorithms In the same manner as topology construction, there are many ways to perform topology maintenance: Global Vs. Local Dynamic Vs. Static Vs. Hybrid Triggered by time, energy, density, random, etc. Some examples of topology maintenance algorithms are: Global DGTRec (Dynamic Global Topology Recreation): Periodically, wake up all inactive nodes, reset the existing reduced topology in the network and apply a topology construction protocol. SGTRot (Static Global Topology Rotation): Initially, the topology construction protocol must create more than one reduced topology (hopefully as disjoint as possible). Then, periodically, wake up all inactive nodes, and change the current active reduced topology to the next, like in a Christmas tree. HGTRotRec (Hybrid Global Topology Rotation and Recreation) Work as the SGTRot, but when the current active reduced topology detects a certain level of disconnection, reset the reduced topology and invoke the topology construction protocol to recreate that particular reduced topology. Local DL-DSR (Dynamic Local DSR-based TM) This protocol, based on the Dynamic Source Routing (DSR) routing algorithm, recreates the paths of disconnected nodes when a node fails. In all of the above protocols can be found in. In Atarraya, two version of each of these protocols are implemented with different triggers: one by time, and the other one by energy. In addition, Atarraya allows the pairing of all the topology construction and topology maintenance protocols in order to test the optimal maintenance policy for a particular construction protocol; it is important to mention that many papers on topology construction have not performed any study on this regard. Further reading Many books and papers have been written in the topic: Topology Control for Wireless Sensor Networks. ACM MobiCom 2003. Topology Control in Wireless Sensor Networks: with a companion simulation tool for teaching and research. Miguel Labrador and Pedro Wightman.