This attribute specifies the Fixed Round-Trip Time (FRTT)
parameter for this connection. FRTT is the sum of the fixed and
propagation delays from the source to a destination and back.
The value of transientBufferExposure divided by the value of FRTT
(in seconds) determines an upper bound for the operational value of
initialCellRate, the rate at which a source should send initially and
after an idle period.
This attribute is ignored under all conditions where the operational
attribute abrConnectionType indicates erSwitch or efciSwitch.