Some industry through the use of containment VPN tunnels, Secure Sockets Layer / Transport Layer Security protocol, or other security applications, started to create. These agreements provide for specific applications end to end communications security, and sometimes discussed here can be an agreement to use the tunnel. IPSec has two modes: transport mode, to ensure that an existing IP Packet from the source to the destination safe; tunnel mode, to an existing IP packet IP packet into a new packet, the new IP Packet format to send to a IPSec tunnel endpoint. Transport mode and tunnel mode can be encapsulated in ESP or AH header.
According to official statistics, estimated that by 2005 the total number of telephone users in China will reach 500 million, 40% phone penetration, Internet penetration rate of 15% of the population. The end of 2001, China reached 100 million fixed telephone services 80390000, mobile phone users reached 100 million 44.8 million. This year the Ministry of Information Industry of China information industry development objectives is to develop 21 million fixed telephone subscribers, 55 million mobile phones, fixed telephone and mobile phone penetration rate of main line penetration rate of 15%. Using the 802.11b wireless network service providers the United States began to open mobile wireless Internet network.