This object indicates a the IGMP filter mode for the group.
include(1) : reception of multicast packets sent to the group
specified by cisMcastGroupAddress is requested
only from the specified IPv4 source addresses
listed in the IGMPv3 Membership Reports.
exclude(2) : reception of multicast packets sent to the group
specified by cisMcastGroupAddress is requested
from all except from the list of IPv4 source
addresses specified in the IGMPv3 Membership
Reports.
The filter mode is determined by the type of Group Record
received in the IGMP Membership Report received by the
device. Groups for which IGMPv1/v2 Membership Reports
are received are considered to have a cisMcastGroupFilterMode
of 'exclude'.