This read-write flag declares whether this particular circuit is permitted to join a Multilink PPP bundle, i.e. whether it can be aggregated with other circuits to form one logical higher-bandwidth PPP link. Setting isMPEligible(1) is a prerequisite step before the switch will consider grouping this circuit with siblings into an MP bundle; leaving it isNotMPEligible(2) forces the circuit to remain standalone even if other MP-capable circuits exist on the same node. A provisioning engineer bonding four DS1 circuits into an 6 Mbps multilink group would need cktMPEligible set to isMPEligible(1) on each of the four member circuits before the bundle negotiation will succeed.