Software Defined Security

We know that there is NFV. (Network Function Virtualization)
It lets us creating any network function component(firewall,Load-Balancer,IPS etc.) virtually.

we can implement Software Defined Security when we create needed network security components (firewall,IPS etc.) virtually.
OSC (Open Security Controller) is a big open source orchestration solution for Software Defined Security.

Sample OSC use-cases may be; "microsegmentation at OpenStack" and "protecting inter-tenant communications"

- Microsegmentation at OpenStack

You can create small groups for your each company department (HR,CRM,Accounting etc.) for example.
If you can create virtual firewalls for each separate department, then you created microsegments for each department and process is microsegmentation.
You could achieve it by using OSC to create separate virtual firewalls.

- Protecting inter-tenant communications

At cloud architectures, there exists multi-tenants using same resources.
Tenants are generally isolated and cant communicate with each other.
But if two separate tenant needs communication, you can provide this communication together with a virtual IPS/IDS solution.
virtual IPS/IDS aims protecting both tenants and this virtual component again created by means of OSC, so it is software defined security.