Currently the Guildford testbed provides a Smart environment, based on an indoor sensor nodes deployment located in the Centre for Communication Systems Research (CCSR). It serves as initial core and experimental micro-cosmos for the envisioned Smart Campus facility.
The IoT node tier consists of 250 freely programmable sensor nodes deployed across all offices of CCSR with various sensing modalities (temperature, light, noise, motion, electricity consumption of attached devices, vibration). The availability of these sensing modalities may vary across some of the nodes. The IoT nodes consist of 200 TelosB based platforms and 50 SunSpots. Other sensor node platforms will be deployed soon in order to achieve additional hardware heterogeneity in the testbed. The nodes’ deployment currently stretches over three floors of the building. Figure 5 provides an example of the final sensors deployment at floor 1 and 2 of the CCSR building. Ground floor deployment is still ongoing and the final layout could vary, however the aim to cover all the desks used by CCSR employees will be maintained. Due to the reduced number of spaces assigned to CCSR the ground floor deployment will result as the sparsest among the three floors.
|Figure 1: An overview of the current IoT node deployment snapshot on two floors of CCSR.|
100 embedded Linux servers (GuruPlug Servers), directly connected to an Ethernet backbone, have been deployed and connected to the sensor nodes for their management. By carefully selecting and configuring sensor nodes to act as sinks at experimentation time, the deployed GWs can offer also the possibility to act at the same time as data GWs realizing a data plane for interconnection of the testbed to the Internet. A server cloud hosts the testbed management servers and allows the on-demand creation of other application servers and data management tools.
|Figure 2: High level network diagram for Guildford Phase 1 deployment|
Figure 2 provides an overview of the network architecture of the Phase 1 deployment. All devices of the IoT tier are connected through a gateway tier to a backbone network were application servers and testbed management servers reside. The data plane of the testbed is realized via wireless links (highlighted in Blue) based on 802.15.4 which can be single/multi-hop between the IoT nodes towards the GW devices. The GWs can act as data GWs, relaying data back to the server using the Ethernet connection provided by the backbone network. An out-of band testbed management and control plane is also realized via USB infrastructure from the IoT nodes to the GW devices, which in turn are connected through an Ethernet backbone towards the testbed management servers. In addition the testbed allows the connection of Smart Displays and end user terminals (laptops, desktops or mobiles) via WiFi and Ethernet towards the internal network, or directly via Bluetooth to the GW devices.
The ratio of GW nodes to IoT nodes is between 1:1 to 1:4, depending on the number of IoT nodes that are deployed in a room and availability of Ethernet ports in the office space for the connection of GWs.
In order to access the testbed and configure and run an experiment a set of tools fully integrated with the Guilford testbed are provided. Examples of these tools are:
- A REST server for accessing the last readings from the different sensors when running some specific collection application;
- A JAVA based GUI called TMON (Testbed MONitor) for exploring the topology by browsing nodes using a semantic description of them and visualizing relation between them such as links and presence of sources of interference (i.e., nearby WiFI access point). After selecting the adequate resource for an experiment, through the TMON GUI the user can also reserve nodes, configure them and automatically run experiments and collect results by providing a first analysis/visualization of them or by storing them in an Experiment Repository;
- An Experiment Repository for experiment results storage/load accessible through a REST interface and working in both modalities as standalone component accessible from custom application or as component already integrated within the TMON GUI.