Shared Extension is when a group of agents has one and the same extension line. During the incoming call the phone will ring at several agents simultaneously.
Mirrored Extensions is when you have one and the same extension line on several phones, in example, in the office, at home and on the cell phone. So when someone calls your extension all you phone sets sharing the same extension will ring.
ShoreTel Sky is the modern phone system for today’s agile, mobile and always-on company. While other cloud-communications companies have added business VoIP services as an afterthought, hosted VoIP is the heart of ShoreTel Sky.