6. Cost-effective solutions

In contrast to MGCP, several open-source solutions attempt to do away with network infrastructure and delegate all VoIP operations to terminals.

The aim is to have only clients (software if possible) on the network, and to use the Internet infrastructure as it is. The solution to this is to distribute the central tasks (registration, directory, call control, etc.) to the terminals, using peer-to-peer sharing techniques.

• Indeed, these networks have capabilities that may be suitable for implementing general ToIP functions. They provide a system for registering entities (rarely authenticated, but with a notion of unique identification) that ensures terminal registration and presence control.

• The directory service is delegated to the terminal: each maintains its...