It has a modular subsystem design so that different implementations can be plugged in and implemented over time. Modular and extensible means modularity in all components of all frameworks, including: Consensus layer Smart contract layer Communication Layer Data Store Identity services (root of trust, to identify the participants).

Values can be assigned to any field variable A CTO file consists of:

● A single namespace, in which all resource declarations are implicitly.

● The overall “model” defines the representation of assets.

● A set of resource definitions that includes assets, transactions, participants, and events.

● Values may be assigned to any field variable.

● The option to import resources from other namespaces.

● When using composer modeling language, the words “asset” and “participant” are reserved.

● Asset ownership instance is defined in a relationship field. (symbol: o)

● The modeling language does not support multiple inheritance.

The ledger system in Hyperledger fabric uses levelDB. By definition, LevelDB allows concurrent writers to safely insert data into the database by providing internal synchronization. LevelDB uses very coarse-grained synchronization which forces all writes to proceed in an ordered, first-come-first-served basis, effectively reduces throughput to a single thread. State database options include LevelDB and CouchDB. LevelDB is the default key-value state database embedded in the peer process. CouchDB is an optional alternative external state database. Like the LevelDB key-value store, CouchDB can store any binary data that is modeled in chaincode (CouchDB attachment functionality is used internally for non-JSON binary data). But as a JSON document store, CouchDB additionally enables rich query against the chaincode data, when chaincode values (e.g. assets) are modeled as JSON data

Hyperledger supports the following two types of transactions. Code deploying transaction: A code deploying transaction submits, updates, or terminates a chaincode. Code invoking transaction: A code invoking transaction is an API call to a chaincode function.