For the last four years, we have only been using the Cloud Collaboration Center (CCC) for our hosted VoIP system. Prior to that, we were using that as well as some managed services for routers and networking. They did manage some of our devices. We had some switches on-prem, but they don't do that anymore. We now have an in-house network team who manages the network devices. Then, in tandem with CDWG, we do some administration of the VoIP phone system with a Call Manager on our side. They host the call manager and all the servers for Call Manager in their data centers. Also, we have a VoIP router on two of our locations where we have phones.
I am using the hosted VoIP system in the cloud. That is what they do. Part of that is the four VoIP routers with their two data centers and one at each of my two locations. For on-prem, we use hosted VoIP calling, i.e. CCC. We don't use any messaging or WebEx with them. All we use are the desk phones and voicemail system right now. We have our desk phones, so we are not even in the cloud using a messaging system. We use Teams totally separate from CDW. All calling is through the CDW CCC hosted VoIP solution, and that is what we use.