WHAT IS VPN?
VPN (Virtual Private Network) is a private network using public network (Internet) in order to connect it to an other network (individual network) or to many remote users.
VPN will replace actual line connection, therefore VPN provides a safety channel through Internet to help users access the server in a reliable way same as access via LAN.
Advandtages:
Encryptation: VPN encrypt all data on VPN tunnel, increase reliability of data transmission.
Saving cost: VPN is wireless and operate through Internet, reduce cost for equipment maintanance.
Data integrity: VPN ensures data integrity, clearly express the properties of network packet.
WHAT IS VPN TUNNEL?
A VPN is established by the combination of tunnel protocol, encryptation, and standard TCP/IP connection.
When an user connect to the internet with a VPN, the VPN creates a connection between the user and the internet that surrounds your internet data like a tunnel, encrypting the data packets user’s device sends. While technically created by a VPN, the tunnel on its own can’t be considered private unless it’s accompanied with encryption strong enough to prevent ISPs from intercepting and reading the internet activity through the tunnel.
The level of encryption the VPN tunnel has depends on the type of tunneling protocol used to encapsulate and encrypt the data going to and from user’s device and the internet. The most popular tunnel protocols are: IPSec, GRE, L2TP, and OpenVPN.
For easier understading, think VPN tunnel as a two-fold process of data encapsulation and data encryption.
Data encapsulation: Encapsulation is the process of wrapping an internet data packet inside of another packet. You can think of this as the outer tunnel structure, like putting a letter inside of an envelope for sending.
Data encryption: However, just having a tunnel isn’t enough. Encryption scrambles and locks the contents of the letter, i.e. your data, so that it can’t be open and read by anyone except the intended receiver.
T. V. Quoc