ISO 7478-1987 PDF
Name in English:
St ISO 7478-1987
Name in Russian:
Ст ISO 7478-1987
Original standard ISO 7478-1987 in PDF full version. Additional info + preview on request
Full title and description
Information processing systems — Data communication — Multilink procedures. This International Standard specifies procedures for combining and coordinating multiple parallel data links at the data‑link layer to provide a single variable‑bandwidth logical link between network‑layer entities (commonly known as multilink or link‑aggregation procedures).
Abstract
Defines multilink procedures in which multiple parallel data links at the data‑link layer are used to provide a variable‑bandwidth data link between network‑layer entities. The standard describes how frames are fragmented, sequenced, transmitted and reassembled across multiple links and addresses control actions such as reset behaviour; it does not specify every interaction with single‑link protocol functions.
General information
- Status: Published (international standard; confirmed stage).
- Publication date: 1987 (first edition published July 1987; main issue recorded 25 June 1987).
- Publisher: International Organization for Standardization (ISO).
- ICS / categories: 35.100.20 (Data link layer / data communication).
- Edition / version: Edition 1 (1987).
- Number of pages: 11 pages (main document).
Scope
This standard specifies the procedures required to operate multilink configurations at the data‑link layer: fragmentation and reassembly of upper‑layer PDUs across a bundle of links, sequence numbering and ordering, timing and retransmission considerations, basic flow and congestion considerations for aggregated links, and control procedures including bundle establishment and reset behaviour. It is intended to describe the multilink protocol primitives and their use between peer data‑link entities rather than to define physical‑layer mechanisms.
Key topics and requirements
- Definition of multilink operation and bundle concept (aggregate virtual link composed of multiple parallel links).
- Fragmentation and reassembly rules for upper‑layer PDUs across member links.
- Sequence numbering and ordering mechanisms to preserve packet order across parallel links.
- Control procedures for bundle establishment, member link addition/removal and MLP reset behaviour (including corrigendum adjustments to reset diagrams/behaviour).
- Interoperability considerations with single‑link protocols and negotiation of multilink capability.
- Basic error handling, retransmission and flow coordination across member links.
Typical use and users
Used by protocol designers, network equipment vendors, implementers of data‑link and link‑aggregation features, telecommunications engineers and standards bodies working on link bundling and multilink solutions. Typical applications include ISDN/leased‑line bundling, early PPP multilink implementations and other scenarios where multiple physical bearer channels are combined to increase logical bandwidth or provide redundancy.
Related standards
Related work includes other data‑link and link‑control standards and multilink/aggregation protocols such as the PPP Multilink Protocol defined in IETF RFCs (RFC 1717 and later RFC 1990), and various ISO/IEC JTC 1/SC 6 publications addressing data communication and link control. A technical corrigendum to ISO 7478 (ISO 7478:1987/Cor 1:1989) corrected specific diagrammatic material (MLP reset) in the original text.
Keywords
multilink; multilink procedures; data link layer; link aggregation; fragmentation; reassembly; sequencing; flow control; MLP; ISO 7478; PPP multilink.
FAQ
Q: What is this standard?
A: ISO 7478:1987 is an International Standard that specifies multilink procedures for data communication — i.e., how multiple parallel data links can be coordinated to form a single variable‑bandwidth logical link at the data‑link layer.
Q: What does it cover?
A: It covers fragmentation/reassembly of PDUs across a bundle of links, sequence numbering and ordering, control procedures for bundle management (including reset behaviour), and interoperability considerations with single‑link protocols.
Q: Who typically uses it?
A: Protocol designers, network engineers and implementers working on link‑aggregation, multilink PPP implementations and related data‑link layer products or research use this standard as a reference. Vendors implementing multilink features in routers, ISDN/leased‑line equipment or PPP stacks are typical users.
Q: Is it current or superseded?
A: ISO 7478:1987 remains the published 1987 edition and was issued with a technical corrigendum in 1989 to correct specific material; implementations in practice have also referenced complementary IETF work on PPP multilink (RFC 1717 / RFC 1990). Users should check current ISO or standards‑body catalogues for any later revisions or replacements.
Q: Is it part of a series?
A: It is part of ISO’s body of standards on information processing systems and data communication maintained under ISO/IEC JTC 1 (specifically work in the SC that handles data communication and link control). It is a standalone standard addressing multilink procedures rather than a numbered multipart series.
Q: What are the key keywords?
A: Multilink, multilink procedures, data link layer, link aggregation, fragmentation, reassembly, sequencing, flow control, MLP, PPP multilink.