The value of the outbound line-rate. measured with kbps.
The upper limit of the line-rate is the value of
hh3cEponUniLineRateMax in the entry. It must be multiple
of the value of hh3cEponUniLineRateStep. The default value of
hh3cEponUniLineRate is the value of hh3cEponUniLineRateMax.