Bandwidth monitoring is supported with ASM only after the traffic is switched from <*,G> to <S,G>. Traffic arriving on separate IOMs from the active UMH and the inactive UMH results in traffic duplication because the pairing of the active and inactive UMH is per IOM, and the IOMs do not have a view of the pair. If the active traffic and the backup traffic arrive on different IOMs, each IOM treats the flow as the active flow and processes the traffic accordingly.