Abstract: The evolution from administrative switching and dispatching exchange to soft-switch system in electricity is an inevitable trend. The soft switch system is the packet IP-based data communications system essentially. It must meet the overall security rectuirements of the electric secondary system. hhis paper analyzes the P2DRR secure model and se- cure risk of electric soft switch system. According to the perspective of system secure isolation, it builds private net- works by using MPI_S VPN technology. And according to secure isolation requirements with different systems, it uses secure isolation device to Internet with other power business system network, uses session border control gateway to in- ternet with other soft switch system network, and uses edge communications agent technology to Internet with terminal access network.

Key words: Electric soft switch, Secure risk, Border control and isolation, MPLS, Communication agent