Mesh Networking: Building, managing, and the works

1. Mesh Networking:Building, managing, and the works Suman Banerjee Wisconsin Wireless and NetworkinG Systems (WiNGS) Laboratory

2. Mesh in the press • Outdoor metro meshes • Many cities, urban downtowns • A set of mesh points connected to gateways • Goal: provide Internet access to users • Business model? • Serve the taxpayer • Run it as an ISP • Single “expert” administrator of the network, and homogenous nodes • But there are other scenarios! Madison, WI downtown 60 mesh points

3. Scenarios I want to talk about • Rural networking • An urban hub connecting a set of villages (say 40 mile range) • Goal: provide Internet access to users • Integrate applications: Distance education, tele-medicine, expert advice • Cost needs to be low • “Not-so-expert” administrator, possibly homogeneous nodes • Indoor (home) meshes • Extend the notion of home-networking • HDTV over wireless: from set-top box to 2nd floor TV • Phone base unit to handset in kitchen • Single “not-so-expert” administrator, heterogeneous nodes

4. Rural networking: Issues • Why meshes make sense? • Can use WiFi (unlicensed) • Most of equipment is low cost and widely available • Technology is getting there to meet the demands

5. Rural networking: Issues • Start at the very beginning • How do we deploy a mesh? • Manage • How do we monitor and manage it? • Improve • If we detect performance problems, what are the right changes to make? • Security • A perennial problem in any domain

6. Deployment Where to place the mesh nodes + how many nodes such that: Budget constraints are met Good fault tolerance and quality of service 40 km • 384 Kbps to each village • Also multicast

7. Deployment Parameter choices: • Many possible locations (> few 100s) • Candidates for deploying mesh nodes • Directional nodes vs. omni-directional nodes • Cost vary depending on nature of antenna systems in use • Interference patterns • Buildings, other hotspots • Gateway locations • Choice of channels in multi-radio nodes

8. Deployment Current state-of-the-art: • Manual inspection based human judgement • Example : MadCity broadband uses consultants • WFI Networks • Neither cost effective nor scalable

9. Management • All of the network management headaches that occur in enterprise • Plus • Those due to multi-hop wireless nature of the network • A control wired backplane does not exist • Control and data on the same “flaky” wireless interface • Performance debugging • User calls up: • “Network is too slow at University Ave. and Randall St.” • Can we find the bottlenecks? • Can we detect route mis-configurations?

10. Management • Current solutions: • Very basic, SNMP based • Essentially monitoring done by the mesh nodes themselves • Can be extremely inaccurate • Data is of low fidelity • Maybe a specialized (low-cost) monitoring infrastructure

11. Improve • How to upgrade the network? • Where do we deploy new nodes? • It is possible to spend money and degrade performance • How many nodes? • What kind of nodes? • Where do we place them?

12. Security • Current planned model • Secure each link • End-to-end security obtained through composition of secure links • What if a mesh node is compromised?

13. Indoor meshes: Issues • Devices manufactured by different vendors • TVs, set-top boxes, phones/handsets, etc. • Interoperability is key • Should be virtually un-managed • Things should just work out of the box! • Security

14. Finally, the applications • Multi-hop wireless has many interactions that reduce end-to-end throughput • HDTV, voice, tele-medicine requires some QoS guarantees • Wireless links are very diverse and have different properties • Some of the MAC protocols adapt poorly • How to manage priorities of these traffic on the mesh

15. Thanks! Suman Banerjee Wisconsin Wireless and NetworkinG Systems (WiNGS) Laboratory