IP GRE Protocol
Generic routing encapsulation (GRE), is a procedure used to create virtual private networks, usually in conjunction with the point-to-point tunneling protocol (PPTP). These are both "tunneling" protocols.
Other People Are Reading
-
Encapsulation
-
The terms "encapsulation" and "tunneling" and interchangeable. Tunneling is the process of placing a packet, including its header, inside another.
Purpose
-
By this method the virtual private network owner can be ensured the same level of privacy as could be achieved by sending the data over a private line, even though it is being transported over a shared resource, such as the Internet.
-
Operating Procedures
-
A packet ready for transmission (including its Internet protocol header) is diverted to the PPTP program, which adds a header. This packet is encrypted in its entirety. The resulting data is given to GRE, which adds on its header and passes the packet to back to the Internet layer, which adds on another IP header for transmission. At the other end, the Internet layer strips off the IP header and passes the packet to the GRE program, which strips off it's header and passes the packet body for decryption. The result of this stage is an IP packet that is released to its destination over the network.
-
References
- Photo Credit tunnel image by Grigori Fedorov from Fotolia.com
