My brother works in an IT support company and his job has something to do with troubleshooting multi-million equipments. Perhaps, this is the reason why some of these companies would opt for second-hand technology like Avaya (which most call centers use), Nortel and used cisco. He is not yet Cisco certified though and he haven't had any formal training on Cisco that is why it is only this technology that he is not allowed to troubleshoot. He is saving money though so that he can take a review class and he would immediately take the certification exam.