This object indicates the IMA group's high water mark
cell rate. The value is the same as the IDCR with all
configured links in the 'active' state.
It is derived according to the following equation:
T1 based group = N * (3622 * (M-1)/M * 2048/2049)
E1 based group = N * (4528 * (M-1)/M * 2048/2049)
where
M = IMA frame size
N = Number of links configured in an IMA group.