Current operating bonding scheme of a G.Bond port.
The possible values are:
none(0) - bonding bypass on a single-BCE (G.998.2 only)
g9981(1) - G.998.1 bonding
g9982(2) - G.998.2 bonding
g9983(3) - G.998.3 bonding
This object maps to the TR-159 attribute
aGroupOperBondScheme.