Fortunately there is an easy to follow video introduction to Quantum from last Summit . The slides to it can be found here as well .
Below are example slides from the presentation of how a virtual network can be build and how it can look like in cloud powered by Openstack, examples: single flat network, multiple flat networks, mixed flat plus private networks, single provider network, multiple per tenant private networks plus single provider network.
- OpenStack Networking (Quantum) Project Update
- More slides about Quantum from Dan Wendlandt at slideshare