# Architectural Overview
As an operator of a Node on the Oasis Network, it is suggested that you have an understanding of the system architecture of the Oasis Network. Here we will provide a high level overview of the Oasis Network's architecture. This overview is used to provide enough guidance to be useful for the purposes of getting started as a Node Operator. Note that not all of these features are available in the Public Testnet, and their design may change in later phases. For more information on our proposed design, see our research papers.
An Entity is an organization or individual with stake on the network. Each Entity has a private key that controls access to the wallet of the Entity. See Entities and Key Management for further information.
A Node is a device (VM, Bare Metal, Container, etc.) that is participating in a committee on the Network. Each Node has a private key that is used for signing operations during block production and a public key, or Node Identity, used for identification. See Entities and Key Management for further information.
A Committee is a set of Nodes that are participating in the same service layer of the Oasis Network. Committees are described in more detail in the Modular Architecture section.
# Modular Architecture
The Oasis Network uses a modular architecture similar to that of a Service Oriented Architecture or a Microservices Architecture. Any given Node participates in one of many different committees. These committees each have different responsibilities in the execution of smart contracts on the Oasis Network. The responsibilities of these committees can be mapped to a set of four different layers: Consensus, Compute (Confidential and Non-confidential), Storage, and Key Management. For a Node Operator, these layers map distinctly to different classes Nodes and potentially to different hardware.
# Committee Responsibilities
In the figure above, we see the flow of transactions in each committee. The details of each committee is best described in our research papers, but we provide this section here as a high level introduction. It should be noted that some aspects of the system are yet to be completed. So the testnet that you might deploy in the Quick Start Guide won't yet function as it is described here.
Although not pictured, the Registry maintains a list of valid Entities, Nodes, the Committees that each Node has registered to participate, and the lifetime of each Node.
# Committee Scheduler
While not a committee unto itself, the Committee Scheduler assigns eligible nodes to specific committees for some duration of epochs. The pool of Nodes to be scheduled are chosen from the Registry.
It is possible that a Node can register for more than one committee to make efficient use of hardware. If, for instance, a Node registers with the possibility of operating as a Storage or Compute Node, the Committee Scheduler will assign it a single job during a given lifetime.
# Consensus Committee
The Consensus Committee is the BFT consensus layer. Its primary function during transaction processing is to reach consensus on the final state of the application that it receives from the Compute layer.
# Networking Protocols
The Oasis Network uses three different protocols for communication:
Confidentiality is achieved in the Oasis Network by relying on trusted execution environments (TEEs) to secure the execution of any given smart contract. Initially, the Oasis Network will utilize Intel SGX. As more TEE technologies mature, we expect to support more than TEEs than Intel SGX.
# Entities and Key Management
Every Node that participates on the network is owned by a specific Entity. This Entity is not only a logical abstraction but is also a critical aspect of the key management model for node operators. The model is as follows:
- An Entity is an organization or individual with stake on the network
- Each Entity's key pair is used for:
- Registering Node IDs (Node's Public Key)
- Token transfers
- A Node is a block producing node on the Oasis Network
- Each Node's key pair is used for:
- Signing actions during block production