Overview
ISO/IEC 4396-4:2023 specifies the complete enrolment procedures for members joining a distributed inter-process communication facility (DIF) or a distributed application facility (DAF) within the Recursive Inter‑Network Architecture. The standard defines the message sequences and information exchange used to initialize a New Member as a fully functioning Member when that member likely has no recent prior membership. It is intended primarily for DIF use but is also applicable to DAFs that need locally scoped synonym assignments.
Key topics and requirements
- Prerequisites: A CDAP (Common Distributed Application Protocol) connection must be established and authentication completed (signalled by a Connect_Response) before enrolment proceeds.
- Information classes:
- Static: fixed DIF definition data.
- Near-static: infrequently changing items (e.g., addresses, QoS-cubes).
- Dynamic: runtime items (e.g., DIF-allocator, directory, routing).
- Resource Information Base (RIB): static and near-static attributes are modelled as RIB attributes; the DIF-allocator has controlled access consistent with access policies.
- Enrolment message flow (naïve/complete enrolment):
- New Member and Existing Member exchange signals beginning with A_Start_R Enrolment (includes address, application process name, Current_Address, Address_Expiration).
- Existing Member sends zero or more A_Create operations to provision static/near-static state; New Member returns A_Create_Response.
- Existing Member issues A_Stop Enrolment with an Immediate Boolean determining whether the New Member may transition immediately to Operational.
- Existing Member sends A_Start Operation; New Member may A_Read and receive A_Read_Response.
- New Member issues A_Start_R Operation and triggers RIB updates so other Members send dynamic information.
- Error handling: on unexpected errors either process should send A_Release (no response requested) and invoke Deallocate.
Applications and users
- Who uses ISO/IEC 4396-4: network architects, protocol designers, implementers of DIF/DAF stacks, system integrators, and research teams building recursive inter-network systems.
- Practical uses: onboarding new IPC processes, automated initialization of distributed nodes, ensuring consistent RIB population, handling re-joins after partitioning, and defining interoperable enrolment behavior in experimental or production recursive network deployments.
Related standards
- ISO/IEC 4396-1: Recursive Inter‑Network Architecture - Reference Model
- ISO/IEC 4396-2: Common Application Connection Establishment Protocol (CACEP) - specifies CDAP/CACEP prerequisites
- ISO/IEC 4396-3: Common Distributed Application Protocol (CDAP)
Keywords: ISO/IEC 4396-4:2023, recursive inter-network architecture, enrolment procedures, DIF, DAF, CDAP, RIB, IPC, enrolment sequence.