Comment 14 for bug 1046121

I'm not sure I understand how the two scenarios diverged so much that it wouldn't be as simple as explaining that the 'external' checkbox allows tenants to attach routers to it and the 'shared' checkbox allows tenants to attach VMs to it.

Even in the tenant networking case, an admin can create VMs on the external network without it being shared for other tenants. At a minimum that should be made clear in the guide because we don't want to perpetuate the idea that the external networks are any different from normal networks.