When the IGMP proxy interface has v1 router present timeout running, it
is in IgmpIntfStateV1RtPresent state. Otherwise, it is in
IgmpIntfStateNonV1RtPresent states. While it is in
IgmpIntfStateV1RtPresent, it only sends out version 1 group membership
report(s). While it is in IgmpIntfStateNonV1RtPresent state, it sends
out version 2 group membership report(s).