A 6-octet read-write MAC address value used as a unique identifier for the System that contains this Aggregator. NOTE-From the perspective of the Link Aggregation mechanisms described in Clause 6, only a single combination of Actor's System ID and System Priority are considered, and no distinction is made between the values of these parameters for an Aggregator and the port(s) that are associated with it; i.e., the protocol is described in terms of the operation of aggregation within a single System. However, the managed objects provided for the Aggregator and the port both allow management of these parameters. The result of this is to permit a single piece of equipment to be configured by management to contain more than one System from the point of view of the operation of Link Aggregation. This may be of particular use in the configuration of equipment that has limited aggregation capability (see 6.7).