ISO/IEC 8473-4:1995 PDF

Information technology — Protocol for providing the connectionless-mode network service: Provision of the underlying service by a subnetwork that provides the OSI data link service

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Title (English):

ISO/IEC 8473-4:1995

Information technology — Protocol for providing the connectionless-mode network service: Provision of the underlying service by a subnetwork that provides the OSI data link service

Document status:: Active
Format:: Electronic (PDF)
Number of pages:: 10
Publication date:: March 2, 1995
Edition:: ISO/IEC IS 8473 edition 1 version 1
ICS:: 35.100.30

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Description (English):

Specifies the way in which the underlying service assumed by the protocol defined by ITU-T Rec. X.233 ISO/IEC 8473-1 is provided by a subnetwork that provides the OSI Data Link service defined by CCITT Rec. X.212 ISO/IEC 8886, through the operation of a Subnetwork Dependent Convergence Function (SNDCF) as described in ISO/IEC 8648. Also provides the PICS proforma for this protocol, in compliance with the relevant requirements and in accordance with the relevant guidance.

Technical details

Technical committee: ISO/IEC JTC 1/SC 6 - Telecommunications and information exchange between systems
SKU: ISO/IEC 8473-4:1995

Abstract

Overview

ISO/IEC 8473-4:1995 (also published as ITU‑T Recommendation X.623) specifies how the connectionless‑mode network protocol (CLNP) - defined in ISO/IEC 8473‑1 - can operate when the underlying service is provided by a subnetwork that implements the OSI Data Link service (ISO/IEC 8886 / CCITT X.212). The standard defines the Subnetwork Dependent Convergence Function (SNDCF) behaviors and includes a PICS proforma (Protocol Implementation Conformance Statement) for conformance testing.

Key topics and requirements

SNDCF model: Defines how SN‑UNITDATA primitives from CLNP map to subnetwork primitives depending on whether the Data Link service is connectionless or connection‑mode.
- For connectionless Data Link service: SN‑UNITDATA → DL‑UNITDATA; DL‑UNITDATA indications map back to SN‑UNITDATA indications. No explicit SNDCF control information is exchanged.
- For connection‑mode Data Link service: SNDCF must establish a DL‑CONNECT (if no existing data link) and then use DL‑DATA to carry SN‑Userdata; DL‑DISCONNECT is used to release links.
SN‑Userdata handling: SN‑Userdata is treated as an ordered octet sequence, transferred transparently between subnetwork attachment points.
Minimum SDU size: The underlying service must support at least a 512‑octet service data unit; segmentation rules apply if SDU limits are smaller.
Quality of Service (QoS): SN‑QoS parameters are conveyed to the Data Link layer; available QoS is known before issuing DL primitives.
PICS proforma (Annex A): Provides the template and instructions required for producing implementation conformance statements in line with ISO/IEC 9646‑1 (X.290).

Applications and who uses it

Network protocol implementers building CLNP stacks that must interwork with OSI Data Link subnetworks.
Device and equipment vendors (routers, gateways, link-layer devices) implementing SNDCF mappings to ensure correct delivery semantics.
Conformance testers and test laboratories using the PICS proforma to validate protocol options and capabilities.
Systems integrators and standards architects designing interoperable OSI-based networks or migrating legacy X.25/OSI deployments.
Standards bodies and technical committees referencing OSI layering, SNDCF behavior, and conformance procedures.

Related standards

ISO/IEC 8473‑1 (CLNP protocol specification)
ISO/IEC 8886 / CCITT X.212 (OSI Data Link service)
ISO/IEC 8648 (Network layer internal organization)
ISO/IEC 9646‑1 / CCITT X.290 (Conformance testing / PICS guidance)
ISO/IEC 7498‑1 / ITU‑T X.200 (OSI Basic Reference Model)

Keywords: ISO/IEC 8473-4, SNDCF, CLNP, OSI data link service, PICS proforma, connectionless-mode network service, DL-UNITDATA, DL-CONNECT.

Related standards

Standards mentioned in the description

Abstract

Overview

Key topics and requirements

SNDCF model: Defines how SN‑UNITDATA primitives from CLNP map to subnetwork primitives depending on whether the Data Link service is connectionless or connection‑mode.
- For connectionless Data Link service: SN‑UNITDATA → DL‑UNITDATA; DL‑UNITDATA indications map back to SN‑UNITDATA indications. No explicit SNDCF control information is exchanged.
- For connection‑mode Data Link service: SNDCF must establish a DL‑CONNECT (if no existing data link) and then use DL‑DATA to carry SN‑Userdata; DL‑DISCONNECT is used to release links.
SN‑Userdata handling: SN‑Userdata is treated as an ordered octet sequence, transferred transparently between subnetwork attachment points.
Minimum SDU size: The underlying service must support at least a 512‑octet service data unit; segmentation rules apply if SDU limits are smaller.
Quality of Service (QoS): SN‑QoS parameters are conveyed to the Data Link layer; available QoS is known before issuing DL primitives.
PICS proforma (Annex A): Provides the template and instructions required for producing implementation conformance statements in line with ISO/IEC 9646‑1 (X.290).

Applications and who uses it

Network protocol implementers building CLNP stacks that must interwork with OSI Data Link subnetworks.
Device and equipment vendors (routers, gateways, link-layer devices) implementing SNDCF mappings to ensure correct delivery semantics.
Conformance testers and test laboratories using the PICS proforma to validate protocol options and capabilities.
Systems integrators and standards architects designing interoperable OSI-based networks or migrating legacy X.25/OSI deployments.
Standards bodies and technical committees referencing OSI layering, SNDCF behavior, and conformance procedures.

Related standards

ISO/IEC 8473‑1 (CLNP protocol specification)
ISO/IEC 8886 / CCITT X.212 (OSI Data Link service)
ISO/IEC 8648 (Network layer internal organization)
ISO/IEC 9646‑1 / CCITT X.290 (Conformance testing / PICS guidance)
ISO/IEC 7498‑1 / ITU‑T X.200 (OSI Basic Reference Model)

Keywords: ISO/IEC 8473-4, SNDCF, CLNP, OSI data link service, PICS proforma, connectionless-mode network service, DL-UNITDATA, DL-CONNECT.

ISO/IEC 8473-4:1995 PDF

Technical details

Abstract

Overview

Key topics and requirements

Applications and who uses it

Related standards

Related standards

Abstract

Overview

Key topics and requirements

Applications and who uses it

Related standards

Related standards

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