Hi, I was wondering do I need a SIP proxy manager for the below scenario: We have multiple locations in different geographical area. On HQ there is 3cx server installed. All other locations are connected MPLS network and reachable. My concerns are: - In order to introduce phones in remote locations, do I need separate PBX systems (3cx or other and bridge them) or can I just add a phone and provision them as we do in the HQ? - Is it necessary to use the SIP proxy manager in each locations other than HQ? If yes, what is the advantage? - How much bandwidth I can expect per call if initiated from the above remote locations? What is the best codec to use that consume less bandwidth and no compromise audio quality?