Configuring VRF-lite on Cisco routers
VRF which stands for virtual routing and forwarding is a feature that allows a single physical router to segregate network traffic into separate virtual routing instances. A router has only one global routing table by default which includes all connected, static and dynamic learned routes. As an analogy VRFs can be viewed as a segregation feature at layer 3 similar to VLANs at layer 2. If we take the example of an ISP with multiple customers by using VRFs we can have separate routing tables per customer on the same router. VRF-lite is a simple form of VRF implementation which is used without MPLS and is appropriate for small to medium enterprises. Being logically isolated each VRF can use overlapping IP address spaces without conflicting with each other.