Application of Trusted Boundary Based on Port Trust Value in Campus Area Network

In this paper, the technology of trusted boundary based on port trust value is discussed. When IP phones are connected to the existing switch-based campus area network, PC is connected to the access port of IP phone. To avoid IP phone is disconnected from the network and PC is directly into the switch port, trusted boundary based on port trust value is applied. In an IP PBX, trusted mode or untrusted mode are supported by IP phone, which is trusted and untrusted. The final run-time port trust on any port is dependent on five decisive factors: Quality of Service, Common Open Policy Service, trust-device type, Cisco Discovery Protocol and phone´s presence on the port. In a typical campus area network with IP phones, trusted boundary based on port trust value is configured. Trusted boundary can ensure the security of the port to which IP phone is connected.