An ATTACHMENT entry containing information common
to a given set of ATTACHMENTs.
The ATTACHMENT Resource represents a PORT or a
pair of PORTs plus the optional associated optical
bypass that are managed as a functional unit.
Because of its relationship to the PORT Objects,
there is a natural association of ATTACHMENT
Resource Indices to the PORT Indices. The
resource index for the ATTACHMENT is equal to the
associated PORT index for 'single-attachment' and
'concentrator' type snmpFddiATTACHMENTClasses.
For 'dual-attachment' Classes, the ATTACHMENT
Index is the PORT Index of the A PORT of the A/B
PORT Pair that represents the ATTACHMENT.