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SOWNet Technologies offers different types of networks for various scenarios. A network topology describes how nodes communicate with each other and the gateway. Different topologies offer different tradeoffs between range, flexibility, and power consumption.

With battery powered nodes, power consumption is critical. The main power drain is the radio, so nodes conserve power by turning off their radio and going into sleep mode whenever possible. However, to receive data, their radio must be on. Special low power communication protocols can reduce power consumption by ensuring the radio is only on when needed. In addition to this power saving on the radio level, much can be gained by using an appropriate type of network. Described below are the basic topologies SOWNet uses in its networks.

Centralized (star)

In a centralized network, sensor nodes (green) communicate directly with the gateway (red). This is very energy efficient, since there is very little overhead and nodes do not need to forward packets for others. This way, they can operate for years on two AA type batteries. However, this type of network is limited by radio range and therefore only rarely used.

Decentralized (clusters)

A decentralized network uses dedicated "router" or "repeater" nodes (blue) to extend radio coverage beyond that of a centralized network. Sensor nodes can also operate for years on two AA batteries in this topology. In SOWNet networks the routers form a self-organising network and relay information to and from the gateway. The routers are more complex and consume much more power than the sensor nodes, because they have to maintain the network and forward data from the nodes and each other. However, because the number of routers is very low compared to the number of sensor nodes, routers can often be powered by mains electricity or larger batteries. Due to its combination of flexibility, efficiency, and limited maintenance (battery replacement), this is our most commonly used topology.

Distributed (mesh)

In a distributed network, all sensor nodes are able to act as routers. This is the most robust and most flexible network setup, but it greatly increases the power consumption of the nodes. Whereas sensor nodes can operate for years in a centralized or decentralized network, they may only last for weeks or months in a distributed network. This type of network is often used for short period outdoor deployments with varying environmental conditions. Alternatively, when all sensornodes can be easily connected to mains power a distributed topology can also be an excellent choice.