Description: The physical port number to be used as the active port. The primary port defaults as the active port if this object is not set.

Rules:

- This object can always be set when ctATMPhyRedundStatus (q.v.) is set to disable(2).

- It cannot be set when ctATMPhyRedundStatus is set to enable(1), ctATMPhyRedundPrimaryRevert (q.v.) is set to automatic(1), and the primary port is deemed good (and therefore usable) by redundancy. Under these conditions, it is meaningless to attempt to manually set the Active Port, as Redundancy would simply reset the active port to the primary again immediately after the set takes place.

- If the primary port has failed, or ctATMPhyRedundPrimaryRevert is set to manual(2), then this object can be set; however, the behaviour of redundancy as a result of the set will depend on the status of ctATMPhyRedundActivation (q.v.) and whether or not the port being set active is good. If RedundActivation is enabled, the set may be countermanded immediately if at any time the port being set is found to be bad (and therefore not usable by Redundancy) and another (good) redundant port is available. If RedundActivation is set to manual(2), then the set will take place, regardless of the status of the port being set. Naturally, if the primary port is restored, the behaviour of Redundancy will depend on whether RedundPrimaryRevert is automatic; if it is, the active port will immediately switch over; otherwise it will remain as-is.

There is a precisely defined relationship between ctATMPhyRedundActivePort, ctATMPhyRedundStatus, ctATMPhyRedundPrimaryRevert, and ctATMPhyRedundActivation. If RedundStatus is disabled, then PrimaryRevert and RedundActivation have no functional meaning and ActivePort becomes the only means by which the redundant ports can be switched. Likewise, if RedundStatus is enabled and PrimaryRevert is automatic, a set of the ActivePort has no functional meaning for as long as the primary port is deemed usable by redundancy. If RedundStatus is enabled but PrimaryRevert is manual, the active port will only be changed through ActivePort or the exercise of RedundActivation. The line of precedence, therefore, fully depends upon the status of Redundancy; if RedundStatus is disabled, then precedence lies with ActivePort by virtue of the fact that there are no other competing methods to switch the active port among the redundant ports. If RedundStatus is enabled, however, PrimaryRevert (an active switching method) and RedundActivation (a passive switching method) have precedence over ActivePort; if PrimaryRevert is set to automatic, then the active port is immediately switched to the primary as soon as it's deemed usable by Redundancy; likewise, if RedundActivation is set to automatic, the currently active port will be switched immediately in the event of port failure. Clearly, then, ActivePort cannot guarantee a set for as long as any automatic part of Redundancy is enabled.

This object is persistent.