Per the project website, Project Calico aims to be:

Simple

Let's remove the complexity

Traditional SDNs are complex, making them hard to deploy and troubleshoot. Calico removes that complexity, with a simplified networking model designed for the demands of today's cloud-native applications.

Scalable

From dev/test to enterprise deployment

Unlike SDNs that require a central controller, limiting scalability, Calico is built on a fully distributed, scale-out architecture. So it scales smoothly from a single developer laptop to large enterprise deployments.

Secure

Policy-based micro-segmentation

Defining secure network policy used to be reserved for skilled network engineers. Calico's powerful micro-segmentation capabilities build on a simple policy language that naturally expresses the developer's intent.