How would you build the MLS network?

“As a network architect, you plan to build a small network in a Multi-Level Security (MLS) environment. Your goal is to enforce the Bell-La Padula (BLP) access control model in the network. In a nut shell, the model defines two mandatory access control rules: No Read Up Rule: a subject (Low) at a lower security level must not read an object (High) at a higher security level. Simply, a Low entity cannot have read-access to a High object. No Write Down Rule: a subject (High) at a higher security level must not write to any object (Low) at a lower security level. Simply, a High entity cannot have a write-access to a Low object. How would you build the MLS network?