Quanta Cloud Technology QuantaMesh QNOS5, Configuration Manual

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Router Alter Option implies a hop by hop option header. MLD 3 types of messages:

General Query: multicast address field is set to 0 (::), is for learning which multicast
addresses have listeners on the subnet.

Group-Specific Query:

Group-and-Source-Specific Query
8.1.9.1. Join Mechanism
When receiving an IGMP query message, clients will respond with IGMP Join Report for the group it is
interested. MLD report must be sent with a valid IPv6 link-local source address, or the unspecific address(::),
if the sending interface has not yet acquired a valid link-local address. Sending reports with the unspecified
address is allowed to support the use of IPv6 multicast in the Neighbor Discovery Protocol
8.1.9.2. Leave Mechanism
Multicast client can leave multicast group any time by sending MLD Done message or sending the MLD
listener report that excludes the group to the link-scope all routers multicast address FF02::2.
If multicast clients leave multicast group quietly without sending notification to the multicast router, the
multicast router stops forwarding traffic after client response timeout.
8.1.10. PIM Protocol
The Protocol Independent Multicast protocol is a simple, protocol-independent multicast routing protocol.
PIM uses an existing unicast routing table and a Join/Prune/Graft mechanism to build a tree. PIM switches
support two types of PIM: sparse mode (PIM-SM) and dense mode (PIM-DM).
PIM-SM is most effective in networks with a sparse population of multicast receivers. In contrast, PIM-DM is
most effective in networks with densely populated multicast receivers. In other words, PIM-DM can be used
if the majority of network hosts request to receive a multicast stream, while PIM-SM might be a better
choice in networks in which a small percentage of network hosts, located throughout the network, wish to
receive the multicast stream.
8.1.10.1. Using PIM-SM as the Multicast Routing Protocol
PIM-SM is used to efficiently route multicast traffic to multicast groups that may span wide area networks
where bandwidth is a constraint.
PIM-SM uses shared trees by default and implements source-based trees for efficiency; it assumes that no
hosts want the multicast traffic unless they specifically ask for it. It creates a shared distribution tree
centered on a defined rendezvous point (RP) from which source traffic is relayed to the receivers. Senders
first send the multicast data to the RP, which in turn sends the data down the shared tree to the receivers.
Shared trees centered on an RP do not necessarily provide the shortest, most optimal path. In such cases,
PIM- SM provides a means to switch to more efficient source-specific trees. A data threshold rate is
configured to determine when to switch from shared-tree to source-tree.