Link Aggregation TLV

This LLDP TLV is used to advertise aggregation capabilities of the link to the remote device. It also provides additional information such as, whether the link is currently in an aggregation (as specified in IEEE 802.1AX), and if it is in an aggregation, advertises the port identifier of the aggregation.

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Link Aggregation TLV
Link Aggregation TLV

The various parameters are:

Field Description
TLV Type Size: 7 bits. Describes the Type of this TLV. This value is always 127 as this is a custom TLV.
TLV Information String Length Size: 9 bits. This field indicates the size of the TLV information being passed. For this TLV this value is nine (9).
802.1 OUI Size: 3 octets. The Organizationally Unique Identifier (OUI) assigned to the organization. This value is always 00-80-C2 for this TLV.
802.1 Subtype Size: 1 octet. This is an internally defined subtype. Its value is always seven (7). This is assigned and managed by the organization.
Aggregation Status

Size: 1 octet. Contains a bitmap of the link aggregation capabilities and the current aggregation status of the link. Only the first two bits are used.

The first bit (bit 0) advertises the aggregation capability for the link. A value of zero (0) indicates that the link is not capable of being aggregated . A value of one (1) indicates that the link is capable of being aggregated.

The second bit (bit 1) advertises the aggregation status for the link. A value of zero (0) indicates that the link is not currently in aggregation. A value of one (1) indicates that the link is currently in aggregation.

Bits 2-7 are reserved.

Aggregated Port ID Size: 4 octets. This field contains the IEEE 802.3 aggregated port identifier. This field is only meaningful if the link is currently a member of an aggregation.