ISO IEC 3309-1993 PDF

Full title and description

ISO/IEC 3309:1993 — Information technology — High-level data link control (HDLC) framing. This standard specifies the framing procedures, bit/byte stuffing and frame handling rules for the HDLC protocol and compatible bit-oriented data link layer protocols used to delimit frames and provide transparent transmission of data.

Abstract

ISO/IEC 3309:1993 defines the frame structure and transparent transmission techniques for HDLC and related bit-oriented link-layer protocols. It describes frame delimiters, address and control fields, frame check sequences, and the procedures for bit (or octet) stuffing and un-stuffing to ensure that control flag sequences do not appear in the information field. The standard supports reliable and unambiguous frame boundary recognition over serial and packet-based links.

General information

• Status: Published (1993); commonly referenced legacy standard for HDLC framing
• Publication date: 1993
• Publisher: International Organization for Standardization (ISO) and International Electrotechnical Commission (IEC) jointly
• ICS / categories: 35.040 Information technology; 35.240 Data communication
• Edition / version: 1993 edition
• Number of pages: Typically 20–30 pages (varies by publishing format)

Scope

This standard specifies the framing procedures for HDLC and compatible bit-oriented data link layer protocols. It covers frame delimiters (flag sequences), address/control fields, frame check sequence (FCS) placement and calculation, and transparent transmission techniques such as bit (or octet) stuffing and un-stuffing. The scope is limited to framing and transparent transmission aspects at the data link layer and does not prescribe higher-layer services, error recovery algorithms beyond FCS, or specific physical layer characteristics.

Key topics and requirements

• Definition of the HDLC flag sequence used to delimit frames and rules for flag recognition.
• Address and control field formats and their placement within frames.
• Frame Check Sequence (FCS) methods and placement for error detection.
• Transparent transmission requirements: bit stuffing (or octet stuffing) rules to prevent flag emulation in information fields.
• Procedures for frame assembly and disassembly, including start/stop of frame processing.
• Handling of abort sequences and error conditions related to framing.
• Compatibility considerations with other bit-oriented link-layer protocols that use similar framing techniques.

Typical use and users

This standard is used by protocol engineers, embedded systems developers, network equipment manufacturers, and telecommunications engineers implementing or maintaining HDLC or HDLC-compatible link-layer protocols. It is referenced when designing serial communication interfaces, modems, routers, multiplexers, and other network devices that require reliable frame delimitation and transparent data transmission at the data link layer.

Related standards

Standards commonly related to ISO/IEC 3309:1993 include other HDLC family and data link standards such as ISO/IEC 4335, ITU-T X.25, ITU-T V-series recommendations (for modem and serial communications), and later ISO/IEC and IEC standards that address link-layer protocols and network architecture. Implementers often refer to protocol-specific documents and national or industry profiles that adapt HDLC framing rules.

Keywords

HDLC, framing, bit stuffing, transparent transmission, frame delimiter, flag sequence, frame check sequence (FCS), data link layer, bit-oriented protocol, ISO/IEC 3309

FAQ

Q: What is this standard?

A: ISO/IEC 3309:1993 is an international standard that specifies HDLC framing and transparent transmission techniques used at the data link layer to delimit frames and prevent control sequence emulation within data.

Q: What does it cover?

A: It covers frame delimitation (flag sequences), address and control fields, frame check sequence placement and calculation, bit or octet stuffing procedures for transparent transmission, and basic handling of framing-related error conditions.

Q: Who typically uses it?

A: Protocol developers, network equipment manufacturers, embedded systems engineers, and telecommunications professionals implementing HDLC or similar bit-oriented link-layer protocols use this standard as a reference for framing behavior.

Q: Is it current or superseded?

A: ISO/IEC 3309:1993 is a legacy standard from 1993 and is often treated as a foundational reference for HDLC framing. Users should check for any newer or amended standards and national/adopted versions that may update or supersede parts of it.

Q: Is it part of a series?

A: Yes. It is part of the broader family of standards that describe HDLC and related data link layer protocols and is commonly referenced alongside other ISO, IEC and ITU-T recommendations covering data link and physical layer interactions.

Q: What are the key keywords?

A: HDLC, framing, bit stuffing, transparent transmission, flag sequence, data link layer, frame check sequence