ACI Contracts

[netbeginner]

Hello All, 

If we split a EPG into multiple micro-EPGs then :

1- Do we still need to apply contracts on main EPGs or we directly expose micro-EPGs to other external EPGs with contract.

2- Is this mandatory to apply both provider and consumer contract on EPG and Any One of this can be sufficient to solve the purpose.

[Robert Burns]

Understand you don't "split an EPG" into multiple uSeg EPGs, you only re-assign endpoints from regular EPGs into uSeg EPGs using various attributes (network or VM based attributes).  A uSeg EPG is still an EPG, and any endpoint can only belong to one EPG at a time.  when a uSeg attribute matches on an endpoint, it's "moved" from it's original base EPG to the uSeg EPG.  So from a contracts perspective, only those contracts attached to the uSeg EPG will now be applied to the endpoint in question.  You need to manually attach any contracts you wish to the uSeg EPG in the same way you would for regular EPGs. 
Contracts don't need to both consume/provide the same contract in most use cases.  Other than being consistent with design, the only other consideration for deciding whether an EPG should be the consume or provider of an contract pertains to shared services.   This is explained in detail in the Contract Guide whitepaper: https://www.cisco.com/c/en/us/solutions/collateral/data-center-virtualization/application-centric-infrastructure/white-paper-c11-743951.html

Robert