IEEE 802.1AX-2020 pdf download

IEEE 802.1AX-2020 pdf download.IEEE Standard for Local and Metropolitan Area Networks一Link Aggregation.
6.3.6 Link Aggregation Group identification
A Link Aggregation Group consists of either
a) One or more Aggregateable links that terminate in the same pair of Systems (or DRNIs) and whose Aggregation Ports have the same operational Key, or
b) A Solitary link.
6.3.6.1 Construction of the Link Aggregation Group Identifier
A unique Link Aggregation Group Identifier (LAG ID) is constructed from the following parameters for each of the communicating Systems:
a) The operational System Identifier
b) The operational Key assigned to the Aggregation Ports in the LAG
c) The Port Identifier, if the link is identified as a Solitary link
A compound identifier formed from the System Identifiers and Keys alone is sufficient to identify a LAG comprising Aggregateable links. However, such an identifier is not sufficient for a LAG comprising a single Solitary link where the Partner System Identifier and operational Key can be zero. Even if these are nonzero, there can be multiple Solitary links with the same System Identifier and operational Key combinations, and it is necessary to include Port Identifiers to provide unique LAG IDs.
Given that
d) S and T are System Identifiers,
e) K and L are the operational Keys assigned to a LAG by S and T, respectively, and
f) P and Q are the Port Identifiers of the Aggregation Ports being attached if the LAG comprises a single Solitary link and zero if the LAG comprises one or more Aggregateable links,
then the general form of the unique LAG ID is [(SKP), (TLQ)j.
To simplify comparison of LAG IDs, it is conventional to order these so that S is the numerically smaller of SandT.
6.3.6.2 Representation of the Link Aggregation Group Identifier
To allow for convenient transcription and interpretation by human network personnel, this standard provides a convention for representing LAG IDs. Using this format,
a) All fields are written as hexadecimal numbers, two digits per octet, in canonical format.
h) Octets are presented in order, from left to right. Within fields carrying numerical significance (e.g., priority values), the most significant octet is presented first, and the least significant octet last.
c) Within fields that carry MAC addresses, organizationally unique identifiers (OUIs) or Company Identifiers (CIDs), successive octets are separated by hyphens (-), in accordance with the hexadecimal representation for MAC addresses defined in IEEE Std 802.
d) Parameters of the LAG ID are separated by commas.
For a link that is Aggregateable, the LAG ID’s Port Identifier components are zero, and the LAG ID derived from this information is represented as follows:
[(SKP), (TLQ)j = [(8000,AC-DE-48-03-67-80,000 1,00,0000), (8000,AC-DE-48-03-FF-FFOOAA,00,0000)]
6.3.7 Selecting a Link Aggregation Group
Each Aggregation Port is selected for membership in the LAG uniquely identified by the LAG ID (composed of operational information, both derived from local administrative parameters and received through the Link Aggregation Control Protocol). Initial determination of the LAG ID is delayed to allow receipt of information from a peer Link Aggregation Control entity; in the event such information is not received, locally configured administrative defaults are assumed for the remote Aggregation Port’s operational parameters.
Where a particular link is known to be Solitary, the complete LAG ID is not required to select the LAG since the link will not be aggregated with any other.
6.3.8 Agreeing on a Link Aggregation Group
Before frames are collected from and distributed to a link, both the local Link Aggregation Control entity and its remote peer (if present) need to agree on the LAG. The Link Aggregation Control Protocol allows each of the communicating entities to check its peer’s current understanding of the LAG ID and facilitates rapid exchange of operational parameters while that understanding differs from its own.
The ability of LACP to signal that a particular link is Solitary (by clearing the Aggregation hit in the
LACPDU Actor State field; see 6.4.2.3) can accelerate the use of the link since, if both Link Aggregation
Control entities know that the link is Solitary, agreement on the LAG ID is not necessary.