Operation Manual – Multicast ProtocolH3C S3610&S5510 Series Ethernet Switches Chapter 3 MLD Snooping Configuration3-3II. Port aging timers in MLD SnoopingTable 3-1 Port aging timers in MLD Snooping and related messages and actionsTimer Description Message beforeexpiryAction afterexpiryRouter port agingtimerFor each routerport, the switchsets a timerinitialized to theaging time of theroute portMLD generalquery or IPv6 PIMhello message ofwhich the sourceaddress is not 0::0The switchremoves this portfrom its router portlistMember port agingtimerWhen a port joinsan IPv6 multicastgroup, the switchsets a timer for theport, which isinitialized to themember port agingtimeMLD reportmessageThe switchremoves this portfrom the IPv6multicast groupforwarding table3.1.3 Work Mechanism of MLD SnoopingA switch running MLD Snooping performs different actions when it receives differentMLD messages, as follows:I. General queriesThe MLD querier periodically sends MLD general queries to all hosts and routers on thelocal subnet to find out whether IPv6 multicast group members exist on the subnet.Upon receiving an MLD general query, the switch forwards it through all ports in theVLAN except the receiving port and performs the following to the receiving port:z If the receiving port is a router port existing in its router port list, the switch resetsthe aging timer of this router port.z If the receiving port is not a router port existing in its router port list, the switch addsit into its router port list and sets an aging timer for this router port.II. Membership reportsA host sends an MLD report to the multicast router in the following circumstances:z Upon receiving an MLD query, an IPv6 multicast group member host respondswith an MLD report.z When intended to join an IPv6 multicast group, a host sends an MLD report to themulticast router to announce that it is interested in the multicast informationaddressed to that IPv6 multicast group.
