MGCP is a master/slave protocol that allows Cisco CallManager to take control of a specific port on a gateway. This has the advantage of centralized gateway administration and provides for largely scalable IP Telephony solutions. With this protocol, the Cisco CallManager knows and controls the state of each individual port on the gateway. It allows complete control of the dial plan from Cisco CallManager, and gives CallManager per-port control of connections to the public switched telephone network (PSTN), legacy PBX, voice mail systems, plain old telephone service (POTS) phones, and so forth. This is implemented with use of a series of plain-text commands sent over User Datagram Protocol (UDP) port 2427 between the Cisco CallManager and the gateway.
All of this means that specific dial-peer are not necessary on the voice gateway because all the call routing is a responsability of the CallManager.
I'm not able to access my old voice mail messages all of a sudden. The recording says something like 'the message is currently not available'. This has never happened before in all the years I have been using this system. I have t...