Issue Description
Q:
How many VRF does NE20 support and how many routes does each VRF support?
Handling Process
A:
1. Supporting VRF of NE20 is related with memory. It can be controlled through license. By default 256M memory supports 128 VRFs and 512M memory supports 255 VRFs. Change license and paf file, it can support 1K at most.
2. The supporting route of each VRF is not limited, but it is related with the memory. 256M memory supports 150,000 routes and 512M memory supports 300,000 routes.
