I am trying to find info that says this is possible, but i find very few examples of this config. My company is merging with another, and we are moving to a whole new domain for this. The plan is to use Lync on premises so that we can continue to integrate with the Cisco VCS tele-presence system. We currently do this using sip uri routing, and the same sip domain (so if you call someone at @domain.com and its not in lync, it goes to the VCS).
Going forward, with a new domain and whole new lync deployment, we want this same functionality so users have one address and it hits all their devices. From what i can find out, to integrate Lync on prem with Exchange Online, i must do a lync hybrid mode deployment using a shared SIP namespace. The problem is if I do that, wouldnt that break the sip uri routing going to the cisco VCS (since now the unknown@domain.com would go to exchange online)?
In the past we had looked at a seperate sip domain for the VCS, but that means multiple "numbers" for each of the users that have both cisco endpoints and lync endpoints, which isnt the best user experience honestly.