Hi,
I'm look for some clarification on the relationship between Domains with regards to SIP domain on Expressway, Presence domain on IM&P and corporate internal/external domains. Basically I'm a bit confused as to the relationship between them. e.g.
internal domain abc.local (where users are)
external domain abc.com
What would you need to make the presence domain and why?
What would you need to make the Expressway SIP domain and why?