Overview
ISO/IEC 10028:1993 defines the abstract relaying functions of a Network layer intermediate system to support the OSI connection-mode Network Service. The standard introduces the Network Internal Layer Service (NILS) as the primary means to describe internal Network layer information flows inside intermediate systems (real subnetworks or network relay systems). It is deliberately abstract - independent of specific protocols or subnetwork technologies - and focuses on how relaying and the invocation of routing functions must behave to support end-to-end OSI Network Service operations.
Key Topics
- Network Internal Layer Service (NILS): An internal-layer abstraction that models primitives, parameters and elementary sequences used inside intermediate systems to represent Network Service behavior.
- Relaying (N-relaying): The functions that relate two instances of NILS (sides A and B) and move Network Service information through an intermediate system.
- Routing (N-routing): The routing function invoked by relaying; the standard defines the interface to routing but does not mandate routing algorithm implementations.
- Primitives and sequences: Definition of NILS primitives and named elementary sequences (e.g., ESTAB, DT, ABORT, REQ, RELF) and their parameters to model connection establishment, data transfer, flow control, reset and release behaviors.
- Mappings and interfaces: How NILS maps to protocol combinations on each side of an intermediate system (N-protocols, NSAP addresses), and the role of harmonization approaches when interconnecting heterogeneous subnetworks.
- Scope limits: Harmonization protocol mechanisms and concrete protocol realizations are explicitly out of scope; the standard provides abstract guidance rather than conformance test criteria.
Applications
ISO/IEC 10028:1993 is intended for:
- Network architects and designers of local area networks (LANs), private packet-switched networks, and interworking units that must support OSI Network Service relaying.
- Standards developers creating Network layer protocol specifications and mappings to ensure relaying requirements are incorporated.
- Vendors implementing network relay systems or subnetwork interfaces that need a reference model for internal Network layer behavior.
Practical uses include designing internal service interfaces, specifying NPDU-to-NILS mappings, and guiding the integration of routing with relaying functions in multi-subnetwork environments.
Related Standards
This standard is primarily conceptual and descriptive - useful as a blueprint for developers and standards authors working with OSI Network layer relaying and intermediate system design.