This value reports the secondary service state of the RS64 element, a supplementary status field distinct from the primary operational state, likely reflecting the condition of a backup or protection-related service function on the component. An admin would check this when investigating redundancy or protection-switching behavior on the element, since it captures state information the primary operational state doesn't cover. For example, a secondary service state indicating a standby or protection condition would tell the admin this component is currently serving a backup role rather than primary traffic.