Team members

David Johnson

Abstract

Building comminity owned wireless mesh networks in developing countries involves a different approach to the typical architecture used in developed countries. Typically the cost of internet services and the quality of services offered is far more limited. Default gateways in all ad-hoc routing protocols only deal with a single default gateway and use VPN's in order to specify a gateway point to the internet if there are multiple possibilities. In cases where there are multiple gateways with different service levels such as low latency for VoIP, high throughput for file downloads, and different costing models – changes are needed to the routing algorithms to be able to accommodate these.

Introduction

Within community wireless networks, a key aspect is the availability of gateway nodes to the Internet. If there is only one gateway to the Internet, this can be advertised to the network as the default route to all the nodes in the network using the routing protocol at hand and all nodes in the network will then be able to reach this default gateway using their routing tables. However if multiple gateways are available and each one of these offers different service levels that user may want to choose between them and it becomes far more complex in terms of routing.

A common solution to the multiple default route problem is to create VPN's to the Internet gateway points from the end point of the network wishing to reach that gateway. This does solve the problem of routing confusion but it does not give one the diversity that would be available if you wanted to route using different gateways which are based on the type of traffic you are using. For example a VoIP call will go through a low latency gateway and a web based request will go though a high throughput gateway. If you use gateway location protocol, other interesting features could be load balancing among equal cost gateways