Queues are present in our everyday lives since they appear whenever there is competition for constrained resources. The ability to model and analyze systems of queues helps to minimize their response time and maximize the use of systems´ resources. This chapter presents a set of elementary queue systems. The geographical area in which the mobile customers can access the service hosted in the server is constrained by the access point coverability radius. The cloud manager and load balancer request a new virtual machines instance at each new customer request, which executes the application. The probability of a request being dropped is the probability of the system bring full. The time between VMs instantiation requests is also assumed to be exponentially distributed with a mean 20 s. Phone calls are assigned to channels until all of them are busy.