How do the different levels of the criminal justice system (federal, state and local) interface to accomplish these “street level enforcement” objectives?

There are four major activities in drug law enforcement:
Source Control – activities targeting cultivation, manufacturing and production of controlled dangerous substances in foreign countries

Interdiction – preventing the successful smuggling of controlled dangerous substances into the United States. This focuses on the smuggling methods of sea, air and land which includes aircraft, vessels, personnel (body carry, swallowing) and parcel shipments among others.

Street-level enforcement – undercover and informant driven investigations targeting the retail sales level of drug trafficking. The text identified the following tactics:

Reversals – Undercover operations where law enforcement poses as drug traffickers
Controlled buy – Undercover operations where confidential informants are used to may purchases of contraband under the direct supervision and direction of a law enforcement investigator

Knock and Talk – overt investigational tactic where fully identified law enforcement makes contact with individuals at a location, usually a residence, and consent to search the residence is obtained

Correctional system – this could also be described as prosecution or courts. Once the defendants are in the correctional system, they have been convicted. The federal penalties for drug trafficking are often times much higher at the federal level as opposed to the state. Also, the effectiveness of federal prosecutions is usually much higher in the areas with the drug trafficking activity.
For this discussion question, address the following:

How do the different levels of the criminal justice system (federal, state and local) interface to accomplish these “street level enforcement” objectives? Give examples of how this would work and please search the library database, internet NEWS sources or web sites for criminal justice agencies.