Multicast Members

Charges the traffic of each IPv4 multicast group to every unicast host that joined it, keyed by the member IP.

Property	Value
GUID	`{51177E0A-7535-46B7-1477-9F0E0E0F9808}`
Layer	L3 Network
Input	Packets
Key type	IPv4 address (member host)
Implementation	Lua — newcg-multicast-member.lua, fed by cg_monitor_hosts.lua and igmp-counter.lua (apps/analyzers/IGMP_multicast)
Trisul App	IGMP_multicast (install from Trisul Apps)
Bucket / Topper	60 s / 300 s
Enabled by default	Yes, once the app is installed

What it measures

Membership comes from IGMPv2 Membership Reports (type 0x16): the report's source IP is recorded as a member of the reported group. IGMPv1, IGMPv3 and Leave messages are not handled, and members are never removed until the probe restarts.
When the Hosts key of a multicast group is flushed, cg_monitor_hosts.lua adds the group's Hosts meters 0, 1 and 2 (rate × 60, in bytes) to each member's key.
Every member gets the full group traffic, whether or not it actually received it. A host in several groups gets the sum of all its groups.
The member's own unicast traffic is not counted here.

One key is one unicast IPv4 host that sent an IGMPv2 report, in Trisul hex form. The UI shows it in dotted decimal.

Key	Meaning
`SYS:GROUP_TOTALS`	Sum of every update made to this group in the interval. A group with N members is added N times, so the total is larger than the real multicast traffic.

ID	Name	Type	Units	Top	Bottom	Description
0	Total	VT_RATE_COUNTER	Bps	1000	0	Hosts meter 0 (Total) of every group this host joined.
1	Recv	VT_RATE_COUNTER	Bps	1000	0	Hosts meter 1 (Received) of every group this host joined.
2	Transmit	VT_RATE_COUNTER	Bps	1000	0	Hosts meter 2 (Transmit) of every group this host joined. Usually 0, because group addresses do not send.
3	Unused Cardinality counter	VT_GAUGE	Uniques	20	20	Reserved cardinality slot. Not populated.
4	Unused Cardinality counter	VT_GAUGE	Uniques	20	20	Reserved cardinality slot. Not populated.