This attribute specifies the portion of the Fixed Round Trip Time
(FRTT) which is added to each ABR call setup which traverses this
interface. The FRTT for the entire call is the sum of the FRTT
portions for each interface traversed by the call. FRTT is used by
the ABR Source or Virtual Source to adjust the value of ICR
according to the rules specified in the ATM Forum TM Version 4.0
specification.
The frttPortion includes propagation delay through the physical
media, plus delays included by the transmission system, plus fixed
components of switch processing delay.
This attribute is used by ATM Networking at call set-up time for
ABR connections directed over this interface.