ISO 20022-6:2013

Overview

ISO 20022-6:2013 - "Financial services - Universal financial industry message scheme - Part 6: Message transport characteristics" defines the transport-level characteristics required to support ISO 20022 business transactions and message definitions. It specifies the MessageTransportSystem behaviour and the MessageTransportMode concept that assigns values for the MessageTransportCharacteristics. ISO 20022-6 focuses on business‑level interoperability (Layer 8/9 in the ISO 20022 layering model) and deliberately does not define wire‑level or protocol‑specific formats.

Key topics and technical requirements

• Layered protocol model: distinguishes the Business Layer (MessageInstances, MessageChoreography, MessageDefinition) from the MessageTransport Layer (TransportMessages). The Messaging Application Layer (examples: AMQP, FTP, HTTP/SOAP, WebsphereMQ) sits beneath.
• MessageInstance vs TransportMessage:
  • MessageInstance contains business payload and must be independent of transport mechanics and addresses.
  • TransportMessage carries the MessageInstance and may include transport-specific headers/envelopes (not registered in the repository).
• MessageTransportCharacteristics:
  • Defined in the ISO 20022 metamodel; values are a closed set and typically mutually exclusive.
  • Each BusinessTransaction is associated with a single MessageTransportMode which sets these characteristics.
  • Example modes registered in the Repository include Reliable Mode, Quick Mode, and Bulk Transfer Mode. (Reliable Mode sample values: DeliveryAssurance = AtLeastOnce; Sender/Receiver Asynchronicity = Asynchronous; MessageDeliveryOrder = Unordered.)
• Idempotency rules:
  • MessageInstance Republication Idempotency: endpoints must behave as if a MessageInstance received multiple times was received once.
  • Transport Message Republication Idempotency: same principle for republished TransportMessages.
• Operational assumptions:
  • Bandwidth Assumption: layer‑8 bandwidth is assumed unconstrained for business choreography (implementers remain responsible for meeting requirements).
  • Security Assumption: transports are assumed to provide secure, unmodified delivery between named endpoints (basic confidentiality/integrity assumed; not a substitute for added security measures).