Relationship between VNI, VRF and RD/RT

[s.ram]

‌Hi All,

I am trying to understand a scenario where there are multiple tenents in a DC fabric. Each tenant had is own VRF. And I have multiple VNIs associated to a tenant. Why should I be configuring RT and RD at a per VNI basis insure instead of at the tenant level?

 Thanks for your time. 

[shulipal]

++ With the help of VRF you can re-use the same IP's in different VRF's. If multiple customers use the same subbet consider you are the Service Provider, how you are going to distinguish between them? - this is where RD pitch in to make the difference about multiple customer if they use the same subnet by adding 64 bit which is unique number prepended to each route within a VRF to identify it as belonging to that particular VRF or customer.

++ RT is an extended BGP community which is used for controlling VRF table. RT will be redistributed into MP-BGP, We can apply route targets to a VRF to control the import and export of routes among it and other VRFs.

++ Coming to your question, why we need to configure RD and RT's at per VNI basis instead of Tenant Level,

each VLAN=VNI=each has different Subnet information to differentiate between them we need to configure them individually.

Hope this helps.