I was wandering if some one can help me out ..... I got few questions , basically I be using SIP and need some general info.....
How many SIP proxy server we need for 60 IP Phones?
If we use SIP proxy server do we still need redirect server?
Do we need a separate server for authentication or SIP proxy server will do authentication...
How we can access voice mail from home or outside office do we need VPN or there is some other way?
If I need to transfer calls from within the office do I need a PBX or it can be done via SIP?
Thanks for your help in advance