Hyperledger Fabric Details in Block Chain

Ordering Service

The ordering service package transactions into blocks to be delivered to peers.
Communication with the service is via channels.

Different configuration options for the ordering service include :
- SOLO

Single node for development

- Kafka : Crash fault tolerant consensus

3 nodes minimum
Odd number of nodes recommended

Channels

Channels provide privacy between different ledgers

- Ledgers exist in the scope of a channel

Channels can be shared across an entire network of peers
Channels can be permissioned for a specific set of participants

- Chaincode is installed on peers to access the worldstate
- Chaincode is instantiated on specific channels
- Peers can participate in multiple channels
- Concurrent execution for performance and scalability

Single Channel Network

All peers connect to the same system channel (blue).
All peers have the same chaincode and maintain the same ledger
Endorsement by peers E0,E1,E2 and E3

Key :

Multi-Channel Network

Peers E0 and E3 connect to the red channel for chaincodes Y and Z
Peers E1 and E2 connect to the blue channel for chaincodes A and B

Key :

Fabric Peer

- Each peer :

Connects to one or more channels
Maintain one or more ledger for each channel
Chaincodes are instantiated in separate docker containers
Chaincodes are shared across channels (no state is stored in chaincode container)
Local MSP (Membership Service Provider) provides crypto material
Emits events to the client application

Client Apllication

Each client application uses Fabric SDK to :

Connects over channels to one or more peers
Connects over channels to one or more orderer nodes
Receivers events from peers
Local MSP provides client crypto material
Client can be written in different languages (Node.js, Go, Java, Python?)

Fabric Certificate Authority

Default (optional) Certificate Authority within Fabric for using Ecerts (long-term identity)
Supports clustering for HA characteristics
Support LDAP for user authentication
Support HSM for security
Can be configured as an intermediate CA