IEEE Std 802.1ABdh-2021 PDF

Full title and description

IEEE Standard for Local and metropolitan area networks — Station and Media Access Control Connectivity Discovery — Amendment 2: Support for Multiframe Protocol Data Units (IEEE Std 802.1ABdh-2021). This amendment specifies the protocols, procedures and managed objects that allow Link Layer Discovery Protocol (LLDP) Type/Length/Value (TLV) sets that exceed the space of a single frame to be transmitted and received using multiple frames, while maintaining backward compatibility with existing LLDP implementations.

Abstract

This amendment (802.1ABdh-2021) defines the mechanisms required to support multiframe LLDP Data Units (LLDPDUs) so that an LLDP agent can advertise and receive larger sets of TLVs than fit in a single LLDPDU. It specifies frame sequencing, additional TLV handling, optional limits to LLDPDU size to meet timing constraints, and clarifications/corrections to existing LLDP behavior to ensure interoperable operation across vendors. The amendment is intended to enable migration to an extended LLDP (often referred to as LLDPv2 or multiframe LLDP) without breaking communication with legacy peers.

General information

• Status: Active Standard.
• Publication date: Published April 19, 2022 (designated 802.1ABdh-2021; Board approval 8 December 2021).
• Publisher: Institute of Electrical and Electronics Engineers (IEEE).
• ICS / categories: Networking; ICS 35.110 (networking / communication).
• Edition / version: Amendment 2 to IEEE Std 802.1AB (designated 802.1ABdh-2021; amends IEEE 802.1AB-2016).
• Number of pages: 56 pages (PDF edition).

Scope

The scope of IEEE 802.1ABdh-2021 is to extend the Station and MAC Connectivity Discovery standard (LLDP) so agents can exchange larger and growing sets of TLVs across IEEE 802 LANs and MANs by splitting and reassembling TLV sets across multiple LLDP frames. The amendment also provides mechanisms to constrain LLDPDU size where timing or media constraints require smaller transmissions, and includes corrections and clarifications to existing LLDP procedures to improve interoperability. The work preserves backwards compatibility so that updated agents can interoperate with legacy LLDP implementations.

Key topics and requirements

• Multiframe LLDPDU support: rules and procedures for breaking an LLDP TLV set across multiple frames and for reassembly at the receiver.
• Frame sequencing and control TLVs to identify and order multiframe LLDP data.
• Backward compatibility: behavior when communicating with peers that do not support multiframe LLDP.
• Optional LLDPDU size restrictions and timing considerations for time-sensitive or constrained links.
• Clarifications and corrections to existing LLDP descriptions, and updated managed objects (MIB) to support the extended functionality.

Typical use and users

Primary users are network equipment vendors (switches, routers, NICs), firmware and OS developers implementing LLDP, network management and monitoring software vendors, and network architects/operators in datacenter, campus, service provider and industrial networks. The amendment is particularly relevant where more descriptive/topology/management metadata must be advertised (for example, extended device inventories, virtualization/site topology, or TSN/industrial automation contexts) and where LLDP is the existing discovery mechanism.

Related standards

IEEE 802.1ABdh-2021 is an amendment to IEEE Std 802.1AB (LLDP — connectivity discovery). It relates to other 802.1 projects and amendments such as IEEE 802.1ABcu (YANG data model for LLDP), IEEE 802.3 (Ethernet) provisions that reference LLDP, and other 802.1 family standards addressing bridge behavior, time-sensitive networking, and management information. It also interoperates with MIBs and management models referenced in IETF documents (for example PTOPO/RFC 2922 is historically relevant to topology MIBs).

Keywords

LLDP, LLDPDU, TLV, multiframe LLDP, LLDPv2, connectivity discovery, topology discovery, LLDP MIB, IEEE 802.1AB, network management, multiframe protocol data units.

FAQ

Q: What is this standard?

A: IEEE Std 802.1ABdh-2021 is Amendment 2 to IEEE Std 802.1AB (LLDP), titled "Support for Multiframe Protocol Data Units", that defines multiframe LLDP mechanisms to advertise larger sets of TLVs.

Q: What does it cover?

A: It covers the protocols, procedures and managed objects needed to transmit and receive LLDP information that does not fit in a single LLDP frame by using multiple LLDP frames, including sequencing, TLV handling, optional LLDPDU size limits, and interoperability rules.

Q: Who typically uses it?

A: Implementers of network device firmware/software (switches, NICs, routers), network management systems, and network architects/operators who rely on LLDP for topology, inventory and configuration discovery use this amendment where larger discovery payloads or richer topology information are required.

Q: Is it current or superseded?

A: As published it is an active IEEE amendment (designated 802.1ABdh-2021) and was published by IEEE on April 19, 2022. It updates IEEE 802.1AB-2016; users should check IEEE records for any later corrigenda or revisions.

Q: Is it part of a series?

A: Yes — it is part of the IEEE 802.1 family of standards for LAN/MAN bridging and higher-layer LAN protocols. It specifically amends IEEE 802.1AB (LLDP) and is related to other 802.1 amendments such as 802.1ABcu (YANG data model) and other 802.1 standards addressing management and TSN features.

Q: What are the key keywords?

A: LLDP, LLDPDU, TLV, multiframe, LLDPv2, topology discovery, management information base (MIB), IEEE 802.1AB.