This read-create integer, measured in seconds, sets how often the switch, acting as IGMP querier, sends Host-Query packets on a given interface to discover active multicast group members. An administrator tunes this interval to balance how quickly the switch detects membership changes against the overhead of frequent query traffic. For example, lowering swIGMPQueryInterval would let the switch detect a client leaving a multicast stream sooner, at the cost of more query traffic on the VLAN.