# Architecture
Source: https://docs.chain.link/dta-technical-standard/concepts/architecture


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The Digital Transfer Agent (DTA) technical standard is designed around a core principle: **separation of concerns**. This ensures a system that is secure, decentralized, and flexible. The architecture clearly distinguishes between the public-facing Request Management contract, where users interact, and the private, secure Request Settlement contract, where fund operations occur.

This design allows the public, multi-tenant DTA Request Management to coexist with private, single-tenant DTA Request Settlement contracts controlled by each Transfer Agent, delivering open discovery with segregated, secure settlement.

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## Core components

### Digital Transfer Agency contracts

#### DTA Request Management

DTA Request Management serves as the central hub for discovery and requests.

**Key Responsibilities:**

- **Request Intake:** Acts as the entry point for all subscription and redemption requests from distributors.
- **Initial Validation & Calculation:** When a Transfer Agent initiates processing, DTA Request Management validates requests against operational rules (such as rate limits and time zones) and calculates final share or payment amounts using the NAVLink feed.
- **Request Routing:** After processing, it forwards finalized request details to the appropriate DTA Request Settlement contract, which is deployed and owned by the fund’s Transfer Agent.

#### DTA Request Settlement

The DTA Request Settlement is owned and deployed by the Transfer Agent. This contract manages the asset movement and the core settlement logic.

**Key Responsibilities:**

- **Token Control Authority:** Holds rights to mint, burn, and transfer the fund’s tokenized shares, enforced via role-based permissions.
- **Asset Custody:** Holds the authority to manage investment product tokens, securely storing newly created tokens during offchain settlements.
- **Settlement Engine:** Receives finalized instructions from DTA Request Management and executes settlements, including transferring payment tokens, managing tokens, and releasing tokens from escrow.
- **Access Control:** Maintains a list of approved DTA Request Management contract addresses allowed to send requests, preventing unauthorized interactions.

## Interaction patterns

Communication between the (DTA Request Management) and (DTA Request Settlement) is designed for flexibility, supporting both local and cross-chain operations.

- **Local Interaction (Same Network):** If DTA Request Settlement is on the same blockchain as DTA Request Management, DTA Request Management makes a direct call to deliver settlement instructions.
- **Remote Interaction (Cross-Network):** If DTA Request Settlement is on a different blockchain, DTA Request Management uses Chainlink CCIP to send settlement instructions, which DTA Request Settlement receives and processes.

This dual-interaction pattern allows the Transfer Agents and Fund Administrators to set up onchain transfer agency services using the DTA Technical Standard.