The value of vRtrIgmpGrpIfMaxSources specifies the maximum number of sources
for which IGMP can have local receiver information based on received
IGMP reports on a SAP belonging to this group-interface. When this
configuration is changed dynamically to a value lower than currently
accepted number of sources, the sources that are already accepted are not
deleted. Only new sources will not be allowed. When this object has a
value of 0, there is no limit to the number of sources.