The idea of wireless mesh networks, which expand the reach of traditional Wi-Fi, is not new. But a lot of fundamental questions still need to be addressed (think design and security). To address those questions, one team of computer science researchers has decided to build their own mesh network – and to share that system with researchers in a host of other fields.
Traditional Wi-Fi networks rely on “access points” (APs) that have landline access to the Internet. In other words, the APs have wires running out of them. These APs then communicate wirelessly to individual laptop users.
Wireless mesh networks also use multiple APs, but they communicate with each other as well as with computer users. One or more of the mesh APs are “root nodes” that have a landline connection to the Internet. Other APs have access to the Internet through these root nodes. This gives a mesh system greater flexibility, because not all of the APs have to have a landline connection to the Internet.
This allows network designers to put APs in places where it is difficult or impossible to give every AP landline access – such as some outdoor settings or military situations.
“CentMesh will help us explore some of the outstanding questions on mesh network design,” says Rudra Dutta, an NC State computer science researcher who is the technical leader on the project. “For example, service continuity. How can we design a system to maximize performance when parts of the system fail, when wireless signals are disrupted, or when users and APs are mobile?” The project will also help researchers address security questions for both systems and users, Dutta says.
But CentMesh will have utility for other research fields as well, from public health to the social sciences. “For example, this could be used for environmental monitoring or to study human behavior and mobility,” explains Mihail Sichitiu, an NC State electrical and computer engineering researcher who is also a technical lead on the project.
One reason CentMesh should be particularly good at enabling multiple research efforts is because the system utilizes a system design and software created by the NC State researchers themselves. “As such,” Dutta explains, “we can control every aspect of network operation and performance. We can make the system do whatever you need it to do.”
Another benefit for researchers is that Centennial Campus is home to companies, homes and recreational facilities as well as academic buildings. “It’s a living laboratory with real-world users,” Sichitiu adds. “Not solely faculty and students.”
CentMesh is also expected to be a useful tool for teaching students about networks and programming. “This lets students learn about something real, not abstract concepts we are explaining to them in the classroom alone,” Dutta says. “Hands-on experience helps bring our class work to life, which gets students more excited about the subject.”
Researchers are close to completing a 14-node version of CentMesh, including four root nodes, that they hope to have up and running in early 2012. This version will cover a small, but heavily populated, section of Centennial Campus – though the long-term goal of the project is to cover all 1,334 acres of the campus.
The CentMesh team has already developed an eight-node mobile “pushcart” network that can be rolled out for temporary deployment. The pushcart was used to pilot the software for CentMesh. In addition, the pushcart can be integrated into the 14-node CentMesh system to temporarily create an expanded 22-node system for experimental use.
CentMesh is being developed and implemented with funding from the U.S. Army Research Office, and collaboration and logistics support from NC State’s Institute for Next Generation IT Systems, and NC State’s Communication Technologies unit.