NDFC behaviour difference

[SandBoyz_16]

Hi fellow members, deploying a NXOS based fabric using NDFC and came across the concept of "multi-attach" and "multi-detach" of networks and VRFs. When coming from an ACI world, this does not exist there. Every network/BD and VRF when created is deployed across the entire fabric in a distributed manner. So why this difference in NDFC ??...when both at the end of the day are VXLAN EVPN fabrics. 

[julian.bendix]

Hey there!

NDFC simply gives you a lot more flexibility for your fabrics .. including the option to only deploy VRFs and BDs to switches where you will need them.

Not sure if that is the real reason behind the choice the developers made there, but to me ACI feels more like they expect endpoint mobility across the entire fabric you build, while for NDFC they give you options to cover specific corner cases and more flexibility/granularity in general.

Hope this helps.
BR
Jules

[M02@rt37 · Accepted solution]

Hello @SandBoyz_16

The difference is mainly architectural... not VXLAN EVPN itself !!!

ACI follow a highly centralized, policy-driven model where APIC treats VRFs and BDs as fabric-wide tenant objects and distributes them everywhere for a consistent “single-system” experience.

On the other hand, NDFC with NxOS keep a more traditional switch-centric approach where leafs are more independent, so multi-attach/multi-detach allows VRFs and networks to exist only on leaf that actually need them, improving scalability.