License: (CC 3.0) BY-NC-SA

What is it?

A virtual network realized as network packets encapsulated using GRE. GRE networks are also referred to as “tunnels”. GRE tunnel packets are routed by the host’s IP routing table, so GRE networks are not associated by Quantum with specific physical networks.

–OpenStack Network (Quantum), Dec 20, 2012, p27