One of Avaya’s critical components for enabling Session Initiation Protocol (SIP) within an enterprise is the Avaya Aura Session Manager (ASM). I have put together a detailed document I've titled “The Gory Details of Session Manager Routing." In it, I provide one of the most complete descriptions of ASM routing to SIP endpoints and SIP servers available to the public. It includes sections on Emergency Routing, User Relationship Element (URE), Implicit User Rule, and the Server Routing Element.
I've included the first few paragraphs for you to scan through, but I really encourage you to download this whitepaper to gain some pretty advanced insight into this topic.
Exerpt from 'The Gory Details of Avaya Aura Session Manager Routing':
A few years ago I downloaded a fantastic document authored by Steve Erickson (Avaya Global Market Introduction,New Solution Engineering team). He presented “Breakout Session: Avaya Aura Session Manager Routing” at the Fall 2011 Avaya Technical Transfer. Within the presentation Steve provided the best description I have ever discovered of the routing decisions made by Avaya Aura Session Manager (ASM). In fact, I have searched extensively through Avaya’s public documents and not found any other that fully describes ASM’s routing decisions. So, I contacted Steve before writing this white paper, and he generously provided additional explanations and detail. What follows is my understanding of what he said.