This object is used to index this table.
At the head end:
When a histogram is created on a per subscriber unit basis,
this object should reflect the MAC address of the subscriber
unit.
When a histogram is created on a per channel basis, this
object must be set to zero(00 00 00 00 00 00).
At the subscriber end:
When creating a histogram, this object must always be set to
zero (00 00 00 00 00 00).