Reliability is a measure of how confident we are that an attempted call will be successful. Reliability can be addressed by reviewing three major areas:

1. The hardware.
2. The software.
3. The network.
   

Redundancy and high-availability are the two terms most often used to describe how reliability is improved. Use of either of these can result in increased reliability.

When we say "Remote management" we're talking about the ability to perform OAM&P (Operations, Administration, Maintenance, and Provisioning) from a system other than the IP PBX, IVR, or other Server.

This is usually set a network (TCP) based applications or web pages that allow administrators and users access to the various OAM&P data and functions.

An IP-PBX is a customer premises business phone system which in years past was called a Private Branch Exchange or PBX. A PBX manages telephones (extensions) throughout the enterprise and acts as a Switch for voice calls, in this case, using VoIP (Voice over IP) technologies.

While an IP-PBX will have the same basic set of call features and functionality as a traditional or legacy PBX it may also have several additional features such as the ability automatically redirect callers to the location of any user, the use of soft phones, etc.