This object sets the multicast TTL threshold used by IGMP forwarding on this interface, controlling how far multicast packets can propagate by limiting them from crossing more than a certain number of routers. Administrators use it to contain multicast traffic within an administrative or topological boundary, preventing it from leaking beyond a defined scope. For example, setting this threshold higher on a boundary interface would allow multicast traffic with a larger remaining TTL to pass through, while a low threshold would block traffic whose TTL has already been mostly consumed.