It's an imperfect analogy but it might look something like this: L1: Central bank (implements monetary policy) L2: Member banks (have accounts at the central

It's an imperfect analogy but it might look something like this: L1: Central bank (implements monetary policy) L2: Member banks (have accounts at the central bank) L3: Non-member banks L4: Clearing house, SWIFT, etc. for interbank payments L5: Credit card networks