I understand how Avaya Aura manages existing phones systems as a sort of super phone system for SIP - but what I don't understand is if you can use just Aura alone as a phone system. Does aura directly support SIP endpoints or Avaya proprietary phones? I asked a few people and can't get a knowledgeable answer?
AURA architectural information is difficult to come by for sure, however as a customer that has just recently deployed AURA, I can tell you what I have found out so far.
AURA Session Manager / ASM (SIP Server) allows both SIP Applications and SIP End-Point connections. You can connect SIP phones directly to ASM, however Communication Manager (CM) is still required for phone features. I have been told CM is not required for just basic features like call routing internal / external, but I have not yet actually connected a SIP phone to ASM to confirm this (I will do next week). So, to directly answer, AURA does support SIP end-point connections and they can be either AVAYA or others SIP phones.