This attribute is applicable and is displayed only for connections for
which the operational Tm abrConnectionType is displayed as
sourceDest or virtualSourceDest.
This attribute indicates the Initial Cell Rate (ICR) parameter for this
connection. ICR is the rate at which a source should send initially
and after an idle period.
For nailed-up connections, this attribute is determined by the
provisioned value of the initialCellRate attribute. For signalled
connections, it is indicated in the ABR Setup Parameters
Information Element.
The ICR for a connection is a value between the MCR and the PCR.
Furthermore, ICR has an upper bound determined by the
transientBufferExposure divided by fixedRoundTripTime.