I am just in the beginning phase of looking into VOIP for my company. We are a small company that is growing at a good rate. Right now we have one main location and two remote offices, with a fourth one coming soon. Right now the network is a real basic layout shown in the first Visio document. As of right now both remote offices connect to the main office via Remote desktop. This is becoming problematic and I am looking at implementing a VPN between the remote offices and the main location. In addition my boss wants me to look into VOIP.
At the current time I have no experience with VOIP, so if it seems like I have no idea what I am talking about it is because I don't. If my boss decides to go with VOIP they will send me for the training. Right now I would like to get a general idea of what I am going to need for hardware, so that I can give my boss the proposed hardware cost.
I know that I will need at least four routers, one for each location though I am not sure what I need. Each remote location has less than 20 users. The main office has less than 50 users, I am not sure what type of Cisco router I would need here.
The second page of the Visio document is what I think my network would be configured like for the VPN and VoIP. Is there any other hardware that is needed or does the Cisco VoIP routers handle all the call routing? I have seen some mention of call management servers but have not found any clear definition of what is exactly needed.
I am also undecided if when using VOIP the internet should be accessible from each location or if all locations should be routed to one point for internet access.
Any and all input would be greatly appreciated.