I have two offices, I want to be able to call some one in office A from office B by just dialing a phone ext.. If I have Cisco Unified Communications 500 Series for Small Business. How can I set this up? do I need static public IP or can I use a dynamic IP service?
Hi, that is called trunking and is explained in the configuration guide. It is recommended that at least one site have static address, but it is not necessary. In that case you will need to configure IPsec tunnel with dynamic DNS and resolution.
If you never configured these things, I recommend you locate a reputable engineer to do that, as these coudl take much time and frustration to you.