Constructing Campus network access mode with ADSL+VPN

ADSL is called asymmetric Digital subscriber line. ADSL is called asymmetric because its two duplex channels are used to transmit data to the user, only a small portion of the bandwidth used to send back to the user's information. ADSL on a pair of copper wire support upload rate 640kbps~1mbps, 1mbps~8mbps rate, effective transmission distance within the 3km~5km range.

The application of ADSL

ADSL LAN users with 4 fixed static IP address, the application of ADSL LAN form network units can be set up in the Chinese public multimedia online company's Web site, providing www, FTP, e-mail and other services; ADSL service has enough bandwidth for LAN users to share, The user can provide Internet service for the whole unit's LAN users through Proxy server. Because ADSL is based on ATM (asynchronous transfer mode) optical cable transmission to the Internet, it can also provide ATM based VPN (virtual private network) services.

What is VPN

A VPN (Virtual private network) is called a virtualized private network. VPN technology is the establishment of a private network in the public network, the data through a secure "encrypted channel" in the public network spread. Companies only need to rent local data lines, connect to the local public information network, all over the organization can communicate with each other, at the same time, enterprises can also use the Public Information network dial-up access devices, so that their users dial to the public information online, you can connect into the enterprise network. VPN provides remote access, which is extensible, manageable, and fully controlled and cost-efficient. Using VPN technology is the trend of enterprise network development in the future.

To implement a VPN connection, you must have a Windows NT or Windows Server-based VPN server on your enterprise intranet that connects to the private network on the intranet and, on the other hand, to the Internet, This requires that the VPN server have a public IP address. When a client communicates with a computer on a private network over a VPN connection, the ISP (Internet service provider) sends all the data to the VPN server and then the VPN server is responsible for transferring all the data to the target computer.

Advantages of using VPN

1. Reduced costs: First, remote users can log in to the local ISP application account to the Internet, connect the Internet as a channel to the private network of the enterprise, communication costs are significantly reduced, second, the enterprise can save the purchase and maintenance of communications equipment costs.

2. Enhanced security: VPN uses three aspects of the technology to ensure the security of communications: Channel protocol, authentication and data encryption. The client makes a request to the VPN server, the VPN server responds to the request and issues an identity challenge to the client, and the client sends the encrypted response information to the VPN server, which checks the response based on the user database, and if the account is valid, the VPN server checks that the user has remote access permissions. If the user has remote access permissions, the VPN server accepts the connection. The client and server public keys generated during the authentication process are used to encrypt the data.

3. Supports the most commonly used network protocols: clients in a network based on IP, IPX, and NetBUI protocols can easily use VPNs.

4. In favor of IP address security: VPN is encrypted, VPN data is transmitted over the Internet, users on the Internet see only public IP addresses and do not see the private network addresses contained within the packet.

Adsl+vpn access method

In the construction of Education metropolitan Area Network, the Education metropolitan area network constructed with VPN technology has been applied in Weifang Education metropolitan area network of Shandong Province. With a large number of data resources, there is a large bandwidth requirements of the Education City Network Center, you can use ATM cable directly connected to the local ISP. The Education metropolitan area Network in each school can apply for a maximum of ADSL lines, the use of ADSL public IP address to establish their own WWW server, truly achieve resource sharing; Each school uses one of these IP addresses to connect to the Education Metropolitan Resource Center via ip-based VPN technology, Thus the virtual Education metropolitan Area Network is formed.