resent value of each alternative 8. Perform sensitivity analysis 9. Make a recommendation Broadband Telecommunications Technologies and Management This is a major shortcoming in public infrastructure projects such as telecommunications where services' provision to isolated communities is usually cost ineffective: services are generally provided through government subsidy [13]. Externality A CBA may at times ignore a parameter because it does not incur a cost or a benefit to the project directly. Such a parameter is called an externality, and a good example is environmental pollution such as CO2: the carbon pollution released into the air had largely been ignored by projects until recently. Clearly, the cost of cleaning the pollution needs to be considered in all projects, which means this externality is now starting to be included in a CBA. An externality may be negative or positive. A negative externality is an overall cost that is not taken into consideration in the production process. A good example is stated above: air pollution. Until recently most factories did not have to pay for the air pollution from their pro- duction processes. If such cost is charged through a mechanism such as a regulatory regime, then it is possible that the price of the produced good is increased. A positive externality occurs when a benefit to the consumer at large cannot be recovered by the producer. For example, a telecommunications operator may charge subscribers for their service usage. However, the social benefits resulting from a robust telecommunications infrastructure, such as security, health, education, and SO on are difficult to quantify and be recovered by the infrastructure owner. If such positive externality can be internalised, it may be possible to reduce the subscriber fees. Network Effects and Platform-mediated Networks The business dynamics of a three-layered broadband telecommunications ecosystem are shaped by platform-mediated networks, and the degree to which these platforms are open. Telecommunications netwo