This attribute specifies the delay metric value beyond which a
destination RID should be considered unreachable. That is, if a
delay metric to a RID is equal to or greater than this value then the
RID is considered to be unreachable in the delay class of service.
Lowering this value has the effect of speeding up the detection of
the loss of reachability to a RID. It also reduces the amount of
Routing Table Update (RTU) traffic generated in this scenario. Care
must be taken to ensure that the value chosen is big enough for the
longest delay path in the network.
This attribute is optional; a default of 128 is used when it is not set.
It is recommended that all nodes in the network be provisioned with
the same cut off value.