Using ADSL + VPN to build Campus Network Access Mode

ADSL is called an asymmetric digital user line. ADSL is called asymmetric because its two duplex channels are used to transmit data to users, and only a small portion of bandwidth is used to send user information back. ADSL supports the upload speed of kbps on a copper-to-copper line ~ 1 Mbps, 1 Mbps ~ 8 Mbps, valid transmission distance between 3km ~ Within the range of 5km.
Application of ADSL
Adsl lan users have four fixed static IP addresses. enterprises applying for access through the adsl lan can set up their websites on the Chinese public multimedia network, provides WWW, FTP, E-mail, and other services. The ADSL service has sufficient bandwidth for LAN users to share. Users can provide Internet services to LAN users of the entire Organization through proxy servers. Because ADSL is based on the ATM asynchronous transmission mode) optical fiber transmission is connected to the Internet, it can also provide an ATM-based VPN Virtual Private Network) service.
What is VPN
VPNVirtual Private Network) is called virtual Private Network. VPN technology refers to the establishment of a private network in the public network, data is transmitted through a secure "encrypted channel" in the public network. Enterprises only need to lease a local data leased line to connect to the local public information network, and local organizations can transmit information to each other. enterprises can also use the dial-up access devices of the Public Information Network, allow your users to dial to the public information network to connect to the enterprise network. VPN provides remote access, which is highly scalable, easy to manage and fully controlled, and can save costs. The adoption of VPN technology is the trend of enterprise network development in the future.
To achieve VPN connection, an enterprise's internal network must have a VPN Server Based on Windows NT or Windows 2000 Server. The VPN Server is connected to the internal private network of the enterprise and the Internet, therefore, the VPN Server must have a public IP address. When a client communicates with a computer in a private network through a VPN connection, the ISPInternet service provider first transmits all the data to the VPN Server, then, the VPN Server is responsible for transmitting all the data to the target computer.
Benefits of Using VPN
1. reduced costs: first, remote users can log on to the Internet by applying for an account from the local ISP, using the Internet as a channel to connect to the private network of the enterprise, greatly reducing the communication cost. Second, enterprises can save on the cost of purchasing and maintaining communication equipment.
2. Enhanced Security: VPN uses three technologies to ensure communication security: Channel Protocol, authentication, and data encryption. The client sends a request to the VPN Server. The VPN Server responds to the request and sends an identity question to the client. The client sends the encrypted response information to the VPN Server. The VPN Server checks the response based on the user database, if the account is valid, the VPN Server checks whether the user has the permission for remote access. if the user has the permission for remote access, the VPN Server accepts the connection. The client and server public keys generated during authentication are used to encrypt data.
3. Support for the most common network protocols: clients in the network based on the IP, IPX, and NetBUI protocols can easily use VPN.
4. Benefits to IP address security: VPN is encrypted. When VPN data is transmitted over the Internet, users on the Internet can only see public IP addresses, but cannot see private network addresses contained in the packets.
ADSL + VPN access method
In terms of the construction of the education man, the education man built with VPN technology has been applied in Weifang City, Shandong Province. An Educational MAN network center with a large amount of data resources and high bandwidth needs can be directly connected to the local ISP using an ATM cable. Each school in the education man can apply for at most one ADSL line and use the public IP address of ADSL to build its own WWW server to truly share resources. Each school uses one of the IP addresses, the IP-based VPN technology is used to connect to the education man resource center to form a virtual education man.