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

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! 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

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 2 nd floor TV Phone base unit to handset in kitchen Single “not-so-expert” administrator, heterogeneous nodes 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 2 nd floor TV Phone base unit to handset in kitchen Single “not-so-expert” administrator, heterogeneous nodes

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 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

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 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

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

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 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

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

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? 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?

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 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

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? 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?

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

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 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

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 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

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